TY - CONF TI - Topographical surface deformation, at Vila Chã de Ourique C2 - 2007/// C3 - 1st Young Geosc. Res. Meeting DA - 2007/// ER - TY - CONF TI - Preliminary data on the sedimentary dinamics at Carcavelos Beach C2 - 2007/// C3 - 1st Young Geosc. Res. Meeting DA - 2007/// ER - TY - CONF TI - Analysis on the Azambuja fault tectonic - a morphotectonic approach. C2 - 2007/// C3 - 1st Young Geosc. Res. Meeting DA - 2007/// ER - TY - CONF TI - Seismic characterization of the Vilariça fault: Comparison between a segmentation model and paleoseismology C2 - 2007/// C3 - Ass. of Env. & Eng. Geol. Ann. Meeting DA - 2007/// ER - TY - CHAP TI - Eddy-mediated interactions between low latitudes and the extratropics AU - Robinson, W.A. T2 - The Global Circulation of the Atmosphere A2 - Schneider, T. A2 - Sobel, A. PY - 2007/// DO - 10.2307/j.ctv1t1kg52.9 SP - 104-142 PB - Princeton University Press ER - TY - JOUR TI - Dynamics of the extratropical response to a tropical Atlantic SST anomaly AU - Li, Shuanglin AU - Robinson, Walter A. AU - Hoerling, Martin P. AU - Weickmann, Klaus M. T2 - Journal of Climate AB - Abstract Previous atmospheric general circulation model (AGCM) experiments revealed that atmospheric responses to a tropical Atlantic sea surface temperature anomaly (SSTA) were asymmetric with respect to the sign of the SSTA. A positive SSTA produced a south–north dipole in geopotential heights, much like the North Atlantic Oscillation (NAO), while a negative SSTA yielded an eastward-propagating wave train, with the northern lobe of the NAO absent. Here these height responses are decomposed into components that are symmetric or antisymmetric with respect to the sign of the SSTA. The symmetric, or notionally linear, component is a nearly south–north dipole projecting on the NAO, while the antisymmetric, or notionally nonlinear, component is a different dipole. Experiments with a diagnostic linear baroclinic model (LBM) suggest that both components are maintained primarily by transient-eddy forcing. Dynamical mechanisms for the formation of the two components are explored using the LBM and a nonlinear barotropic vorticity equation model (BVM). Transient-eddy feedback is sufficient to explain the linear response. The NAO-like linear response occurs when the initial heating induces transient-eddy forcing in the exit of the Atlantic jet. The structure of the background absolute vorticity in this region is such that this transient-eddy forcing induces a nearly north–south dipole in anomalous geopotential heights. When the nonlinear self-interaction of this transient-induced low-frequency perturbation is included in the BVM, the dipole axis tilts to the east or west, resulting in a response that is nonlinear about the sign of the forcing. DA - 2007/// PY - 2007/// DO - 10.1175/JCLI4014.1 VL - 20 IS - 3 SP - 560-574 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000244093000012&KeyUID=WOS:000244093000012 ER - TY - JOUR TI - Sensitivity of the latitude of the surface westerlies to surface friction AU - Chen, G. AU - Held, I.M. AU - Robinson, W.A. T2 - Journal of the Atmospheric Sciences AB - The sensitivity to surface friction of the latitude of the surface westerlies and the associated eddy-driven midlatitude jet is studied in an idealized dry GCM. The westerlies move poleward as the friction is reduced in strength. An increase in the eastward phase speed of midlatitude eddies is implicated as playing a central role in this shift. This shift in latitude is mainly determined by changes in the friction on the zonal mean flow rather than the friction on the eddies. If the friction on the zonal mean is reduced instantaneously, the response reveals two distinctive adjustment time scales. In the fast adjustment over the first 10–20 days, there is an increase in the barotropic component of zonal winds and a substantial decrease in the eddy kinetic energy; the shift in the surface westerlies and jet latitude occurs in a slower adjustment. The space–time eddy momentum flux spectra suggest that the key to the shift is a poleward movement in the subtropical critical latitude associated with the faster eastward phase speeds in the dominant midlatitude eddies. The view is supported by simulating the upper-tropospheric dynamics in a stochastically stirred nonlinear shallow water model. DA - 2007/// PY - 2007/// DO - 10.1175/JAS3995.1 VL - 64 IS - 8 SP - 2899-2915 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34548173532&partnerID=MN8TOARS ER - TY - CONF TI - Nitrogen emissions from agricultural sources AU - James, K.M. AU - Aneja, V.P. C2 - 2007/// C3 - 100th Annual Conference and Exhibition of the Air and Waste Management Association 2007, ACE 2007 DA - 2007/// VL - 4 SP - 2469-2476 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84933527128&partnerID=MN8TOARS ER - TY - CONF TI - Measurements and modeling of ammonia and hydrogen sulfide emissions from a commercial swine finishing operation in North Carolina AU - Blunden, J. AU - Aneja, V.P. C2 - 2007/// C3 - 100th Annual Conference and Exhibition of the Air and Waste Management Association 2007, ACE 2007 DA - 2007/// VL - 1 SP - 330-342 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84933528204&partnerID=MN8TOARS ER - TY - RPRT TI - Propagation of Freshwater Mussels for Release into North Carolina Waters AU - Eads, C. AU - Levine, J.F. AU - Bogan, A. AU - Raley, M A3 - NC Department of Transportation DA - 2007/5/5/ PY - 2007/5/5/ M1 - FHWA/NC/2006-37 PB - NC Department of Transportation SN - FHWA/NC/2006-37 ER - TY - RPRT TI - Bivalves as Biomonitors in the Lake Crabtree Watershed, North Carolina: A Preliminary Field and Laboratory Study to Examine the Valve Gape Responses of Non-Native and Native Freshwater Bivalves to Polychlorinated Biphenyls AU - Bucci, J.P. AU - Hurley, J. AU - Thorp, E.C. AU - Law, M. AU - Levine, JF A3 - Nekton Research DA - 2007/// PY - 2007/// PB - Nekton Research ER - TY - CONF TI - Characterization of Salmonella Isolates From Sentinel Bivalves (Corbicula flumenia) Using Serotypying, Pulsed Field Gel Electrophoresis (PFGE), Multi-Locus Sequence Typing (MLST) and Antimicrobial Resistance Analysis (ARA) AU - Li, X. AU - Mascarelli, P. AU - Raley, M. AU - Patel, P. AU - Gerner-Smidt, P. AU - Gebreyes, W.A. AU - Levine, J. T2 - International Association of Food Protection (IAFP) C2 - 2007/7// CY - Lake Buena Vista, Florida DA - 2007/7// PY - 2007/7// ER - TY - CONF TI - Molecular Evidence For A Novel Phylogenetic Placement Of The Carolina Creekshell, Villosa vaughaniana (LEA, 1836) AU - Raley, ME AU - Bogan, Ae AU - Eads, Cb AU - Levine, Jf T2 - Freshwater Mollusk Conservation Society C2 - 2007/3// CY - Little Rock, Arkansas DA - 2007/3// PY - 2007/3// ER - TY - CONF TI - Propagation and Culture Of Freshwater Mussels In North Carolina AU - Eads, C. AU - Kittel, C.J. AU - Wilson, G AU - Bradford, R.J. AU - Bogan, A.E. AU - Levine, J.F. T2 - Freshwater Mollusk Conservation Society C2 - 2007/3// CY - Little Rock, Arkansas DA - 2007/3// PY - 2007/3// ER - TY - CONF TI - The Use Of Mark-Recapture To Understand Seasonal Changes In A Mussel Bed AU - Eads, C. AU - Bogan, A.E. AU - Levine, J.F. T2 - Freshwater Mollusk Conservation Society C2 - 2007/3// CY - Little Rock, Arkansas DA - 2007/3// PY - 2007/3// ER - TY - CONF TI - Magnetic Resonance Imaging of Live Freshwater Mussels (Unionidae) AU - Holliman, F.M. AU - Davis, D. AU - Bogan, A.E. AU - Kwak, T.J. AU - Cope, G. AU - Levine, J.F. T2 - Freshwater Mollusk Conservation Society C2 - 2007/3// CY - Little Rock, Arkansas DA - 2007/3// PY - 2007/3// ER - TY - CONF TI - 16s Sequence Analysis of Cellulose Degrader Isolates from an Invasive Mussel Species AU - Szempruch, A.J. AU - Caldwell, J.M. AU - Levine, J.F. T2 - American Society for Microbiology C2 - 2007/10// CY - Greensboro, North Carolina DA - 2007/10// PY - 2007/10// ER - TY - JOUR TI - Occurrence and Removal of Marine Biotoxins for the Seawater Reverse Osmosis Treatment Process: Phytoplankton and Domoic Acid Correlations at the West Basin MWD Seawater Desalination Pilot Plant in El Segundo, CA T2 - American Membrane Technology Association DA - 2007/1/1/ PY - 2007/1/1/ ER - TY - CHAP TI - Modeling and Analysis of Ozone and Nitrogen Oxides in the Southeast United States National Parks AU - Aneja, V. P. AU - Tong, Q. AU - Kang, D. AU - Ray, J. D. T2 - Air Pollution Modeling and Its Application XVII PY - 2007/4/3/ DO - 10.1007/978-0-387-68854-1_2 SP - 13–19 PB - Springer US SN - 9780387282558 UR - http://dx.doi.org/10.1007/978-0-387-68854-1_2 ER - TY - JOUR TI - Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California Bight, 2003–2004 AU - Schnetzer, Astrid AU - Miller, Peter E. AU - Schaffner, Rebecca A. AU - Stauffer, Beth A. AU - Jones, Burton H. AU - Weisberg, Stephen B. AU - DiGiacomo, Paul M. AU - Berelson, William M. AU - Caron, David A. T2 - Harmful Algae AB - Abundances of Pseudo-nitzschia spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1500 km2 were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles harbor (12.7 μg DA L−1). Particulate DA levels were an order of magnitude lower in spring of 2004 (February and March), but DA concentrations per cell at several sampling stations during 2004 exceeded previously reported maxima for natural populations of Pseudo-nitzschia (mean = 24 pg DA cell−1, range = 0–117 pg DA cell−1). Pseudo-nitzschia australis dominated the Pseudo-nitzschia assemblage in spring 2004. Overall, DA-poisoning was implicated in >1400 mammal stranding incidents within the SCB during 2003 and 2004. Ancillary physical and chemical data obtained during our regional surveys in 2004 revealed that Pseudo-nitzschia abundances, particulate DA and cellular DA concentrations were inversely correlated with concentrations of silicic acid, nitrogen and phosphate, and to specific nutrient ratios. Particulate DA was detected in sediment traps deployed at 550 and 800 m depth during spring of 2004 (0.29–7.6 μg DA (g sediment dry weight)−1). The highest DA concentration in the traps was measured within 1 week of dramatic decreases in the abundances of Pseudo-nitzschia in surface waters. To our knowledge these are the deepest sediment trap collections from which DA has been detected. Sinking of the spring Pseudo-nitzschia bloom may constitute a potentially important link between DA production in surface waters and benthic communities in the coastal ocean near Los Angeles. Our study indicates that toxic blooms of Pseudo-nitzschia are a recurring phenomenon along one of the most densely populated coastal stretches of the SCB and that the severity and magnitude of these events can be comparable to or greater than these events in other geographical regions affected by domoic acid. DA - 2007/4// PY - 2007/4// DO - 10.1016/j.hal.2006.11.004 VL - 6 IS - 3 SP - 372-387 J2 - Harmful Algae LA - en OP - SN - 1568-9883 UR - http://dx.doi.org/10.1016/j.hal.2006.11.004 DB - Crossref KW - domoic acid KW - harmful algal blooms KW - Los Angeles KW - Pseudo-nitzschia KW - Southern California ER - TY - JOUR TI - On Measuring the Critical Diameter of Cloud Condensation Nuclei Using Mobility Selected Aerosol AU - Petters, Markus D. AU - Prenni, Anthony J. AU - Kreidenweis, Sonia M. AU - DeMott, Paul J. T2 - Aerosol Science and Technology AB - Cloud condensation nuclei (CCN) instruments determine the so-called “critical diameter” for activation of particles into cloud droplets at a fixed water supersaturation. A differential mobility analyzer is often used to size-select particles for purposes of scanning for the critical diameter. Usually the diameter where 50% of the particles have activated to cloud droplets is assumed to be equal to the critical diameter. We introduce a model that describes the transfer of polydisperse charge-equilibrated particles through an ideal differential mobility analyzer followed by transit through an ideal CCN instrument. We show that if the mode diameter of the polydisperse size distribution exceeds the critical diameter of the particles, multiply-charged particles may lead to nonmonotonic CCN counter response curves (plots of CCN-active fraction vs. mobility diameter) that exhibit multiple peaks, rather than a simple sigmoidally-shaped curve. Hence, determination of the 50% activation diameter is ambiguous. Multiply-charged particles significantly skew the CCNc response curves when sampling particles with critical diameters exceeding 0.1 μ m from particle size distributions with mode diameters also larger than the critical diameter. We present a method for inversion of CCN counter data that takes multiple-charging effects into account, and demonstrate its application to laboratory data. Our calculated CCN counter response curves are in good agreement with observations, and can be used to infer the critical activation diameter for a specified supersaturation. DA - 2007/8/30/ PY - 2007/8/30/ DO - 10.1080/02786820701557214 VL - 41 IS - 10 SP - 907-913 J2 - Aerosol Science and Technology LA - en OP - SN - 0278-6826 1521-7388 UR - http://dx.doi.org/10.1080/02786820701557214 DB - Crossref ER - TY - JOUR TI - Potential impact of Owens (dry) Lake dust on warm and cold cloud formation AU - Koehler, Kirsten A. AU - Kreidenweis, Sonia M. AU - DeMott, Paul J. AU - Prenni, Anthony J. AU - Petters, Markus D. T2 - Journal of Geophysical Research AB - [1] Owens lake bed is one of the largest sources of particulate matter in the western hemisphere. Because of the fine-grained nature of this dust, it is easily lofted above the atmospheric boundary layer, where it may affect cloud formation. Further, unlike many other soil types, it has a large fraction of soluble material (∼3–37% of the mass on an organic-matter-free basis), so it can impact both warm and cold clouds. In this study, we measure the hygroscopicity, cloud condensation nucleus (CCN) activity, and ice nucleating ability of Owens (dry) Lake dust. Our studies confirm that a fraction of the Owens (dry) Lake dust (35% by number for particle sizes ∼200 nm) is quite hygroscopic and has CCN activity comparable to that of sodium chloride (50 nm particles activate at 0.33% supersaturation). These hygroscopic dust particles can readily initiate droplet formation at modest supersaturations in the atmosphere and may significantly impact liquid clouds in the southwestern United States. The less hygroscopic fraction had only modest CCN activity. However, such particles may still activate as cloud droplets at atmospheric supersaturations and could potentially modify cloud properties if particles with diameters larger than ∼300 nm are present. The less hygroscopic fraction also was found to nucleate ice heterogeneously at relative humidities significantly lower than required for homogeneous freezing of aqueous particles at temperatures colder than −40°C. In convective systems, this dust may be lofted to the upper troposphere where it may impact convection strength and onset conditions for ice formation in cold clouds. DA - 2007/6/28/ PY - 2007/6/28/ DO - 10.1029/2007JD008413 VL - 112 IS - D12 J2 - J. Geophys. Res. LA - en OP - SN - 0148-0227 UR - http://dx.doi.org/10.1029/2007JD008413 DB - Crossref ER - TY - JOUR TI - Cloud droplet activation of secondary organic aerosol AU - Prenni, Anthony J. AU - Petters, Markus D. AU - Kreidenweis, Sonia M. AU - DeMott, Paul J. AU - Ziemann, Paul J. T2 - Journal of Geophysical Research: Atmospheres AB - Measurements of hygroscopicity and cloud condensation nuclei (CCN) activity were conducted on secondary organic aerosol (SOA) formed in a smog chamber. SOA precursors included α ‐pinene, β ‐pinene, Δ 3 ‐carene, and toluene, representative of both naturally and anthropogenically emitted organic species. Measured CCN activation was comparable for all of the species studied and occurred at humidity conditions which are readily attained in the atmosphere. Further, there was little variation in hygroscopic growth between compounds. However, measured droplet activation conditions were inconsistent with hygroscopicity measured below water saturation and Köhler theory expressions based on Raoult’s law for several parameterizations for water activity. In the atmosphere, SOA may compose a large fraction of atmospheric particulate matter and will often exist internally mixed with inorganic species. Using the current results, we compare SOA to insoluble organic species to calculate CCN activation from mixed organic‐sulfate particles for a range of atmospheric conditions. We find that droplet activation behavior of mixed particles containing SOA is the same as that of mixed particles for which the organic component is nonhygroscopic, except for cases in which there are low particle concentrations, low updraft velocities, and the aerosol composition is dominated by organics. DA - 2007/5/26/ PY - 2007/5/26/ DO - 10.1029/2006JD007963 VL - 112 IS - D10 J2 - J. Geophys. Res. LA - en OP - SN - 0148-0227 UR - http://dx.doi.org/10.1029/2006JD007963 DB - Crossref ER - TY - JOUR TI - Pulse of the seafloor: Tidal triggering of microearthquakes at 9°50′N East Pacific Rise AU - Stroup, D. F. AU - Bohnenstiehl, D. R. AU - Tolstoy, M. AU - Waldhauser, F. AU - Weekly, R. T. T2 - Geophysical Research Letters AB - Unequivocal evidence of tidal triggering is observed for microearthquakes (−0.4 to 2.0 M L ) recorded between October 2003 to April 2004 near 9°50′N on the East Pacific Rise (EPR). Although semidiurnal tidal stress changes are small (<2 kPa), seismicity exhibits a significant (>99.9%) nonrandom temporal distribution, with events occurring preferentially near times of peak extension. Due to the proximity of this site to an ocean tidal node, where changes in sea surface height are minimal, periodic stress changes are dominated by the solid Earth tide. In contrast, previous studies on the Juan de Fuca Ridge have shown microearthquake triggering to be a response to seafloor unloading during times of low ocean tide. The modulation of 9°50′N microearthquakes by small‐amplitude periodic stresses is consistent with earthquake nucleation within a high stressing rate environment that is maintained near a critical state of failure by on‐axis magmatic and hydrothermal processes. DA - 2007/8// PY - 2007/8// DO - 10.1029/2007GL030088 VL - 34 IS - 15 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1029/2007GL030088 DB - Crossref ER - TY - JOUR TI - Aerosol-cloud drop concentration closure for clouds sampled during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign AU - Fountoukis, Christos AU - Nenes, Athanasios AU - Meskhidze, Nicholas AU - Bahreini, Roya AU - Conant, William C. AU - Jonsson, Haflidi AU - Murphy, Shane AU - Sorooshian, Armin AU - Varutbangkul, Varuntida AU - Brechtel, Fred AU - Flagan, Richard C. AU - Seinfeld, John H. T2 - Journal of Geophysical Research: Atmospheres AB - This study analyzes 27 cumuliform and stratiform clouds sampled aboard the CIRPAS Twin Otter during the 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) experiment. The data set was used to assess cloud droplet closure using (1) a detailed adiabatic cloud parcel model and (2) a state‐of‐the‐art cloud droplet activation parameterization. A unique feature of the data set is the sampling of highly polluted clouds within the vicinity of power plant plumes. Remarkable closure was achieved (much less than the 20% measurement uncertainty) for both parcel model and parameterization. The highly variable aerosol did not complicate the cloud droplet closure, since the clouds had low maximum supersaturation and were not sensitive to aerosol variations (which took place at small particle sizes). The error in predicted cloud droplet concentration was mostly sensitive to updraft velocity. Optimal closure is obtained if the water vapor uptake coefficient is equal to 0.06, but can range between 0.03 and 1.0. The sensitivity of cloud droplet prediction error to changes in the uptake coefficient, organic solubility and surface tension depression suggest that organics exhibit limited solubility. These findings can serve as much needed constraints in modeling of aerosol‐cloud interactions in the North America; future in situ studies will determine the robustness of our findings. DA - 2007/4/26/ PY - 2007/4/26/ DO - 10.1029/2006JD007272 VL - 112 IS - D10 J2 - J. Geophys. Res. LA - en OP - SN - 0148-0227 UR - http://dx.doi.org/10.1029/2006JD007272 DB - Crossref ER - TY - JOUR TI - Phytoplankton and bacterial assemblages in ballast water of U.S. military ships as a function of port of origin, voyage time, and ocean exchange practices AU - Burkholder, JoAnn M. AU - Hallegraeff, Gustaaf M. AU - Melia, Gregory AU - Cohen, Andrew AU - Bowers, Holly A. AU - Oldach, David W. AU - Parrow, Matthew W. AU - Sullivan, Michael J. AU - Zimba, Paul V. AU - Allen, Elle H. AU - Kinder, Carol A. AU - Mallin, Michael A. T2 - Harmful Algae AB - We characterized the physical/chemical conditions and the algal and bacterial assemblages in ballast water from 62 ballast tanks aboard 28 ships operated by the U.S. Military Sealift Command and the Maritime Administration, sampled at 9 ports on the U.S. West Coast and 4 ports on the U.S. East Coast. The ballast tank waters had been held for 2–176 days, and 90% of the tanks had undergone ballast exchange with open ocean waters. Phytoplankton abundance was highly variable (grand mean for all tanks, 3.21 × 104 viable cells m−3; median, 7.9 × 103 cells m−3) and was unrelated to physical/chemical parameters, except for a positive relationship between centric diatom abundance and nitrate concentration. A total of 100 phytoplankton species were identified from the ballast tanks, including 23 potentially harmful taxa (e.g. Chaetoceros concavicornis, Dinophysis acuminata, Gambierdiscus toxicus, Heterosigma akashiwo, Karlodinium veneficum, Prorocentrum minimum, Pseudo-nitzschia multiseries). Assemblages were dominated by chain-forming diatoms and dinoflagellates, and viable organisms comprised about half of the total cells. Species richness was higher in ballast tanks with coastal water, and in tanks containing Atlantic or Pacific Ocean source waters rather than Indian Ocean water. Total and viable phytoplankton numbers decreased with age of water in the tanks. Diversity also generally decreased with water age, and tanks with ballast water age >33 days did not produce culturable phytoplankton. Abundance was significantly higher in tanks with recently added coastal water than in tanks without coastal sources, but highly variable in waters held less than 30 days. Bacterial abundance was significantly lower in ballast tanks with Atlantic than Pacific Ocean source water, but otherwise was surprisingly consistent among ballast tanks (overall mean across all tanks, 3.13 ± 1.27 × 1011 cells m−3; median, 2.79 × 1011 cells m−3) and was unrelated to vessel type, exchange status, age of water, environmental conditions measured, or phytoplankton abundance. At least one of four pathogenic eubacteria (Listeria monocytogenes, Escherichia coli, Mycobacterium spp., Pseudomonas aeruginosa) was detected in 48% of the ballast tanks, but toxigenic strains of Vibrio cholerae were not detected. For ships with tanks of similar ballasting history, the largest source of variation in phytoplankton and bacteria abundance was among ships; for ships with tanks of differing ballasting histories, and for all ships/tanks considered collectively, the largest source of variation was within ships. Significant differences in phytoplankton abundance, but not bacterial abundance, sometimes occurred between paired tanks with similar ballasting history; hence, for regulatory purposes phytoplankton abundance cannot be estimated from single tanks only. Most tanks (94%) had adequate records to determine the source locations and age of the ballast water and, as mentioned, 90% had had ballast exchange with open-ocean waters. Although additional data are needed from sediments that can accumulate at the bottom of ballast tanks, the data from this water-column study indicate that in general, U.S. Department of Defense (DoD) ships are well managed to minimize the risk for introduction of harmful microbiota. Nevertheless, abundances of viable phytoplankton with maximum dimension >50 μm exceeded proposed International Maritime Organization standards in 47% of the ballast tanks sampled. The data suggest that further treatment technologies and/or alternative management strategies will be necessary to enable DoD vessels to comply with proposed standards. DA - 2007/8// PY - 2007/8// DO - 10.1016/j.hal.2006.11.006 VL - 6 IS - 4 SP - 486-518 J2 - Harmful Algae LA - en OP - SN - 1568-9883 UR - http://dx.doi.org/10.1016/j.hal.2006.11.006 DB - Crossref KW - bacteria KW - ballast water exchange KW - harmful algae KW - phytoplankton KW - ship KW - transport ER - TY - CONF TI - An Integrated Living and Learning Community for First and Second Year Undergraduate Women in Science & Engineering AU - Titus-Becker, K. AU - Rajala, S. AU - Bottomley, L. AU - Raubenheimer, D. AU - Cohen, J. AU - Bullett, K. AU - Grant, S. AU - Cobb Payton, F. AU - Kirkman, A. AU - Kirby, B. AU - Krause, W. AU - Thomas, C. C2 - 2007/// C3 - American Society for Engineering Education 2007 Annual Conference and Exposition DA - 2007/// UR - https://peer.asee.org/an-integrated-living-and-learning-community-for-first-and-second-year-undergraduate-women-in-science-and-engineering ER - TY - JOUR TI - The use of wet chemical oxidation with high-amplification isotope ratio mass spectrometry (WCO-IRMS) to measure stable isotope values of dissolved organic carbon in seawater AU - Osburn, Christopher L. AU - St-Jean, Gilles T2 - Limnol. Oceanogr. Methods AB - Few measurements of the carbon stable isotope value (δ 13 C) of marine dissolved organic carbon (DOC), the largest pool of reduced carbon in the ocean, have been made because of analytical obstacles due to the interference of halides and the low amount of DOC in seawater. By using concentrated persulfate in a wet chemical oxidation organic carbon analyzer coupled to an isotope ratio mass spectrometry (WCO‐IRMS) the analytical obstacles are overcome. Key to this method is reducing the persulfate blank and increasing the IRMS signal with larger amplifier gain resistors. After these simple modifications, a 2 mL sample provides enough signal to make precise measurements of DOC concentration and δ 13 C value on up to 15 samples per day. Sodium persulfate (1.68 mol L −1 ) is cleaned by pre‐heating and sparging with ultrahigh purity helium. In the WCO analyzer, 6 mL cleaned persulfate is added to 2 mL sample at 98°C for 8.5 min to completely oxidize DOC to CO 2 . After quantitative measurement by nondispersive IR, the gases contained in the exhaust are swept through a cleanup reactor, separated by a GC column and introduced to the IRMS for δ 13 C measurement. Complete recovery of the DOC and δ 13 C values was confirmed with two DOC standards added individually to seawater. IRMS precision was confirmed by measuring a range of sea water samples. On several coastal water samples measured using this system, δ 13 C‐DOC values ranging from −22‰ to −25‰. These results were consistent with published reports of seawater δ 13 C‐DOC using other methods. DA - 2007/10// PY - 2007/10// DO - 10.4319/lom.2007.5.296 VL - 5 IS - 10 SP - 296-308 ER - TY - JOUR TI - Comparison of the optical properties of dissolved organic matter in two river-influenced coastal regions of the Canadian Arctic AU - Retamal, Leira AU - Vincent, Warwick F. AU - Martineau, Christine AU - Osburn, Christopher L. T2 - Estuarine, Coastal and Shelf Science AB - The optical characteristics of coloured dissolved organic matter (CDOM) were analyzed in the Great Whale River and adjacent Hudson Bay (55° N, 77° W) in the eastern Canadian Low Arctic, and in the Mackenzie River and adjacent Beaufort Sea in the western Canadian High Arctic (70° N, 133° W). Sampling was during ice-free open water conditions. Both rivers contained high concentrations of dissolved organic carbon (3 and 6 mg DOC l−1 in the Great Whale River and Mackenzie River, respectively) and CDOM (a320 of 11 and 14 m−1), resulting in a substantial load of organic matter to their coastal seas. There were pronounced differences in the CDOM characteristics of the two rivers, notably in their synchronous fluorescence scans (SFS). The latter showed that the Mackenzie River was depleted in humic materials, implying a more mature catchment relative to the younger, more recently glaciated Great Whale River system. SFS spectra had a similar shape across the freshwater–saltwater transition zone of the Great Whale plume, and DOC was linearly related to salinity implying conservative mixing and no loss by flocculation or biological processes across the salt front. In contrast, there were major differences in SFS spectral shape from the Mackenzie River to the freshwater-influenced coastal ocean, with a marked decrease in the relative importance of fulvic and humic acid materials. The SFS spectra for the coastal Beaufort Sea in September–October strongly resembled those recorded for the Mackenzie River during the high discharge, CDOM-rich, snowmelt period in June, but with some loss of autochthonous materials. These results are consistent with differences in freshwater residence time between the Mackenzie River and Great Whale River coastal ocean systems. Models of arctic continental shelf responses to present and future climate regimes will need to consider these striking regional differences in the organic matter content, biogeochemistry and optics between waters from different catchments and different inshore hydrodynamic regimes. DA - 2007/3// PY - 2007/3// DO - 10.1016/j.ecss.2006.10.022 VL - 72 IS - 1-2 SP - 261-272 J2 - Estuarine, Coastal and Shelf Science LA - en OP - SN - 0272-7714 UR - http://dx.doi.org/10.1016/j.ecss.2006.10.022 DB - Crossref KW - Arctic KW - coloured dissolved organic matter KW - climate change KW - DOC KW - optics KW - synchronous fluorescence ER - TY - JOUR TI - Photobleaching of Dissolved Organic Material from a Tidal Marsh-Estuarine System of the Chesapeake Bay† AU - Tzortziou, Maria AU - Osburn, Christopher L. AU - Neale, Patrick J. T2 - Photochemistry and Photobiology AB - Wetlands and tidal marshes in the Rhode River estuary of the Chesapeake Bay act as important sources of dissolved organic carbon and strongly absorbing dissolved organic matter (DOM) for adjacent estuarine waters. The effects of solar exposure on the photochemical degradation of colored DOM (CDOM) were examined for material derived from different sources (estuarine and freshwater parts of the Rhode River, sub-watershed stream, marshes) in this estuarine ecosystem. Consistent with changes in fluorescence emission, absorption loss upon exposure to different portions of the solar spectrum (i.e. different long-pass cut-off filters) occurred across the entire spectrum but the wavelength of maximum photobleaching decreased as the cut-off wavelength of the filter decreased. Our results illustrate that solar exposure can cause either an increase or a decrease in the CDOM absorption spectral slope, S(CDOM), depending on the spectral quality of irradiation and, thus, on the parameters (e.g. atmospheric composition, concentration of UV-absorbing water constituents) that affect the spectral characteristics of the light to which CDOM is exposed. We derived a simple spectral model for describing the effects of solar exposure on CDOM optical quality. The model accurately, and consistently, predicted the observed dependence of CDOM photobleaching on the spectral quality of solar exposure. DA - 2007/6// PY - 2007/6// DO - 10.1111/j.1751-1097.2007.00142.x VL - 83 IS - 4 SP - 782-792 ER - TY - JOUR TI - The cost effectiveness of standard and alternative sediment and turbidity control systems on construction sites in North Carolina AU - Wossink, A. AU - Mitasova, H. AU - McLaughlin, R. T2 - Water Resources Research Institute News of the University of North Carolina DA - 2007/// PY - 2007/// IS - 360 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-39749149040&partnerID=MN8TOARS ER - TY - CONF TI - TerraStream: From elevation data to watershed hierarchies AU - Danner, A. AU - M?lhave, T. AU - Yi, K. AU - Agarwal, P.K. AU - Arge, L. AU - Mitasova, H. AB - We consider the problem of extracting a river network and a watershed hierarchy from a terrain given as a set of irregularly spaced points. We describe TERRASTREAM, a "pipelined" solution that consists of four main stages: construction of a digital elevation model (DEM), hydrological conditioning, extraction of river networks, and construction of a watershed hierarchy. Our approach has several advantages over existing methods. First, we design and implement the pipeline so that each stage is scalable to massive data sets; a single non-scalable stage would create a bottleneck and limit overall scalability. Second, we develop the algorithms in a general framework so that they work for both TIN and grid DEMs. Furthermore, TERRASTREAM is flexible and allows users to choose from various models and parameters, yet our pipeline is designed to reduce (or eliminate) the need for manual intervention between stages. C2 - 2007/// C3 - GIS: Proceedings of the ACM International Symposium on Advances in Geographic Information Systems DA - 2007/// DO - 10.1145/1341012.1341049 SP - 212-219 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959666821&partnerID=MN8TOARS ER - TY - CONF TI - Morphological evolution of a shoreline on a decadal time scale AU - Overton, M. AU - Mitasova, H. AU - Recalde, J.J. AU - Vanderbeke, N. C2 - 2007/// C3 - Proceedings of the Coastal Engineering Conference DA - 2007/// SP - 3851-3861 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84873027031&partnerID=MN8TOARS ER - TY - JOUR TI - Collaborative environmental management: What roles for government? AU - Marshall, Graham R. T2 - ECOLOGICAL ECONOMICS AB - Faculty development (FD) is important for continued professional development, but expense and distance remain challenging. These challenges could be minimized by the free and asynchronous nature of social media (SM). We sought to determine the utility and effectiveness of conducting a national online FD activity on Facebook by assessing participants' perceptions and use and facilitators' challenges.An educational activity of a national FD program was managed on a closed Facebook group. Activities included postings of educational technology goals, abstracting an article, and commenting on peers' postings. Sources of quantitative data included the Facebook postings and the survey responses. Surveys before, after, and 6 months after the activity assessed knowledge, attitudes and self-reported behaviors. Sources of qualitative data were the open-ended survey questions and the content of the Facebook postings.All participants completed the FD activity and evaluations, yielding 38 postings and 115 comments. Before the activity, 88% had a personal Facebook account, 64% were somewhat/very confident using Facebook, 77% thought SM would be useful for professional networking, and 12% had used it professionally. Six months after the activity, professional usage had increased to 35%. Continued use of Facebook for future presentations of this FD activity was recommended by 76%. Qualitative analysis yielded 12 types of Facebook postings and 7 themes related to using SM for FD.Conducting a national FD activity on Facebook yielded excellent participation rates and positive participant impressions, and it affected professional usage. Facebook may become an additional tool in the educator's toolbox for FD as a result of its acceptability and accessibility. DA - 2007/4/20/ PY - 2007/4/20/ DO - 10.1016/j.ecolecon.2006.05.024 VL - 62 IS - 2 SP - 373-374 SN - 0921-8009 ER - TY - JOUR TI - Position of the Snake River watershed divide as an indicator of geodynamic processes in the greater Yellowstone region, western North America AU - Wegmann, Karl W. AU - Zurek, Brian D. AU - Regalla, Christine A. AU - Bilardello, Dario AU - Wollenberg, Jennifer L. AU - Kopczynski, Sarah E. AU - Ziemann, Joseph M. AU - Haight, Shannon L. AU - Apgar, Jeremy D. AU - Zhao, Cheng AU - Pazzaglia, Frank J. T2 - GEOSPHERE AB - Tectonic processes, flexure due to crustal loading, and dynamic mantle flow each impart a unique imprint on topography and geomorphic responses over time scales of 104 to 106 yr. This paper explores the mobility of regional drainage divides as a key geomorphic metric that can distinguish between the various processes driving crustal deformation in the greater Yellowstone region of the northwestern United States. We propose a new analysis that quantifies the differences between the location of the present-day drainage divide from divides synthetically generated from filtered topography to determine the relative impact of tectonic and dynamic mantle influences on landscape development. The greater Yellowstone region is an opportune location for this investigation because contrasting models have been proposed to explain the parabolic shape of elevated topography and active seismicity that outline the imprint of hypothesized hotspot activity. Drainage divides synthesized from topography filtered at 50, 100, and 150 km wavelengths within the greater Yellowstone region show that the locations of the actual and synthetic Snake River drainage divides are controlled by both dynamic and flexural mechanisms in the eastern greater Yellowstone region, but by flexural mechanisms only in the western greater Yellowstone region. The location of the actual divide deviates from its predicted position in the filtered topography where tectonic controls, such as active faults (e.g., Centennial and Teton faults), have uplifted large footwall blocks. Our results are consistent with the notion of a northeastward-propagating greater Yellowstone region topographic and seismic parabola, and suggest that Basin and Range extension follows from, rather than precedes, greater Yellowstone region dynamic topography. Furthermore, our analysis suggests that eastward migration of the Snake River drainage divide lags behind the continued northeastward propagation of high-standing topography associated with the Yellowstone geophysical anomaly by 1–2 m.y. DA - 2007/8// PY - 2007/8// DO - 10.1130/GES00083.1 VL - 3 IS - 4 SP - 272-281 SN - 1553-040X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-71849090379&partnerID=MN8TOARS ER - TY - CONF TI - Geology of the Hangay Nuruu, Central Mongolia AU - Bayasgalan, A. AU - Carson, R. AU - Jordon, B. AU - Wegmann, K. C2 - 2007/// C3 - Twentieth Annual Keck Research Symposium in Geology Proceedings DA - 2007/// SP - 2-9 SN - 9781604238815 ER - TY - BOOK TI - The good earth: Introduction to earth sciences AU - McConnell, D. A. AU - Steer, D. AU - Owens, K. AU - Knight, C. AU - Park, L. E. DA - 2007/// PY - 2007/// PB - Boston: McGraw-Hill Science Engineering SN - 9780073256504 ER - TY - JOUR TI - Critical thinking for civic thinking in science AU - Gerwing, J. AU - McConnell, D. AU - Stearns, D. AU - Adair, S. T2 - Academic Exchange Quarterly DA - 2007/// PY - 2007/// VL - 11 IS - 3 SP - 160-164 ER - TY - JOUR TI - Eutrophication and cyanobacteria blooms in run-of-river impoundments in North Carolina, USA AU - Touchette, Brant W. AU - Burkholder, Joann M. AU - Allen, Elie H. AU - Alexander, Jessica L. AU - Kinder, Carol A. AU - Brownie, Cavell AU - James, Jennifer AU - Britton, Clay H. T2 - LAKE AND RESERVOIR MANAGEMENT AB - Abstract We compared monthly data taken during the dry summer growing season of 2002 in 11 potable water supply reservoirs (19–85 years old based on year filled) within the North Carolina Piedmont, including measures of watershed land use, watershed area, reservoir morphometry (depth, surface area, volume), suspended solids (SS), nutrient concentrations (total nitrogen, TN; total Kjeldahl nitrogen, TKN; nitrate + nitrite, NO3− + NO2−; total phosphorus, TP; total organic carbon), phytoplankton chlorophyll a (chla) concentrations, cyanobacteria assemblages, and microcystin concentrations from monthly data taken during the dry summer 2002 growing season. The reservoirs were considered collectively or as two subgroups by age as “mod.” (moderate age, 19–40 years post-fill, n = 5) and “old” (74–85 yr post-fill, n = 6). The run-of-river impoundments were meso-/eutrophic and turbid (means 25–125 μg TP/L, 410–1,800 μg TN/L, 3–70 μg chla/L and 5.7–41.9 mg SS/L). Under drought conditions in these turbid systems, there was a positive relationship between chla and both TN and TP, supported by correlation analyses and hierarchical ANOVA models. The models also indicated significant positive relationships between TN and TP, and between SS and both TP and TN. Agricultural land use was positively correlated with TKN for the reservoirs considered collectively, and with TN, TKN, TP, and chla in mod. reservoirs. In models considering the reservoirs by age group, TN:TP ratios were significantly lower and NO3− + NO2− was significantly higher in old reservoirs, and these relationships were stronger when reservoir age was used as a linear predictor. Cyanobacteria assemblages in the two reservoir age groups generally were comparable in abundance and species composition, and comprised 60–95% (up to 1.9 × 106 cells/mL) of the total phytoplankton cell number. Potentially toxic taxa were dominated by Cylindrospermopsis raciborskii and C. philippinensis. Although known microcystin producers were low in abundance, microcystin (< 0.8 μg/L) was detected in most samples. TP and chla were significant predictors of total cyanobacterial abundance. The data suggest that at present these turbid, meso-/eutrophic reservoirs have moderate cyanobacteria abundance and low cyanotoxin (microcystin) levels over the summer growing season, even in low-precipitation seasons that favor cyanobacteria. Accelerated eutrophication from further watershed development is expected to promote increased cyanobacterial abundance and adversely affect the value of these reservoirs as potable water supplies. DA - 2007/6// PY - 2007/6// DO - 10.1080/07438140709353921 VL - 23 IS - 2 SP - 179-192 SN - 1040-2381 KW - chlorophyll a KW - cyanobacteria KW - eutrophic KW - microcystin KW - nitrogen KW - nutrients KW - phosphorus KW - reservoirs KW - turbid ER - TY - JOUR TI - First Atlantic record of the puffin Cerorhinca (Aves, Alcidae) from the Pliocene of North Carolina AU - Smith, N. Adam AU - Olson, Storrs L. AU - Clarke, Julia A. T2 - JOURNAL OF VERTEBRATE PALEONTOLOGY AB - (2007). First Atlantic record of the puffin Cerorhinca (Aves, Alcidae) from the Pliocene of North Carolina. Journal of Vertebrate Paleontology: Vol. 27, No. 4, pp. 1039-1042. DA - 2007/12/12/ PY - 2007/12/12/ DO - 10.1671/0272-4634(2007)27[1039:FAROTP]2.0.CO;2 VL - 27 IS - 4 SP - 1039-1042 SN - 0272-4634 ER - TY - JOUR TI - Reliability analyses of anomalies of NCEP/NCAR reanalyzed wind speed and surface air temperature in climate change research in China AU - Shi, X. H. AU - Xu, X. D. AU - Xie, L. A. T2 - Acta Meteorologica Sinica DA - 2007/// PY - 2007/// VL - 21 IS - 3 SP - 320-333 ER - TY - JOUR TI - Seagrasses and eutrophication AU - Burkholder, JoAnn M. AU - Tomasko, David A. AU - Touchette, Brant W. T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - This review summarizes the historic, correlative field evidence and experimental research that implicate cultural eutrophication as a major cause of seagrass disappearance. We summarize the underlying physiological responses of seagrass species, the potential utility of various parameters as indicators of nutrient enrichment in seagrasses, the relatively sparse available information about environmental conditions that exacerbate eutrophication effects, and the better known array of indirect stressors imposed by nutrient over-enrichment that influence seagrass growth and survival. Seagrass recovery following nutrient reductions is examined, as well as the status of modeling efforts to predict seagrass response to changing nutrient regimes. The most common mechanism invoked or demonstrated for seagrass decline under nutrient over-enrichment is light reduction through stimulation of high-biomass algal overgrowth as epiphytes and macroalgae in shallow coastal areas, and as phytoplankton in deeper coastal waters. Direct physiological responses such as ammonium toxicity and water-column nitrate inhibition through internal carbon limitation may also contribute. Seagrass decline under nutrient enrichment appears to involve indirect and feedback mechanisms, and is manifested as sudden shifts in seagrass abundance rather than continuous, gradual changes in parallel with rates of increased nutrient additions. Depending on the species, interactions of high salinity, high temperature, and low light have been shown to exacerbate the adverse effects of nutrient over-enrichment. An array of indirect effects of nutrient enrichment can accelerate seagrass disappearance, including sediment re-suspension from seagrass loss, increased system respiration and resulting oxygen stress, depressed advective water exchange from thick macroalgal growth, biogeochemical alterations such as sediment anoxia with increased hydrogen sulfide concentrations, and internal nutrient loading via enhanced nutrient fluxes from sediments to the overlying water. Indirect effects on trophic structure can also be critically important, for example, the loss of herbivores, through increased hypoxia/anoxia and other habitat shifts, that would have acted as “ecological engineers” in promoting seagrass survival by controlling algal overgrowth; and shifts favoring exotic grazers that out-compete seagrasses for space. Evidence suggests that natural seagrass population shifts are disrupted, slowed or indefinitely blocked by cultural eutrophication, and there are relatively few known examples of seagrass meadow recovery following nutrient reductions. Reliable biomarkers as early indicators of nutrient over-enriched seagrass meadows would benefit coastal resource managers in improving protective measures. Seagrasses can be considered as “long-term" integrators (days to weeks) of nutrient availability, especially through analyses of their tissue content, and of activities of enzymes such as nitrate reductase and alkaline phosphatase. The ratio of leaf nitrogen content to leaf mass has also shown promise as a “nutrient pollution indicator” for the seagrass Zostera marina, with potential application to other species. In modeling efforts, seagrass response to nutrient loading has proven difficult to quantify beyond localized areas because long-term data consistent in quality are generally lacking, and high inter-annual variability in abundance and productivity depending upon stochastic meteorological and hydrographic conditions. Efforts to protect remaining seagrass meadows from damage and loss under eutrophication, within countries and across regions, are generally lacking or weak and ineffective. Research needs to further understand about seagrasses and eutrophication should emphasize experimental studies to assess the response of a wider range of species to chronic, low-level as well as acute, pulsed nutrient enrichment. These experiments should be conducted in the field or in large-scale mesocosms following appropriate acclimation, and should emphasize factor interactions (N, P, C; turbidity; temperature; herbivory) to more closely simulate reality in seagrass ecosystems. They should scale up to address processes that occur over larger scales, including food-web dynamics that involve highly mobile predators and herbivores. Without any further research, however, one point is presently very clear: Concerted local and national actions, thus far mostly lacking, are needed worldwide to protect remaining seagrass meadows from accelerating cultural eutrophication in rapidly urbanizing coastal zones. DA - 2007/11/9/ PY - 2007/11/9/ DO - 10.1016/j.jembe.2007.06.024 VL - 350 IS - 1-2 SP - 46-72 SN - 1879-1697 KW - biomarkers KW - eutrophication KW - food webs KW - grazers KW - nitrogen KW - phosphorus KW - seagrass KW - watershed ER - TY - JOUR TI - Multitiered Health Assessment of Atlantic Menhaden in the Pamlico River, North Carolina AU - Johnson, A. K. AU - Law, J. M. AU - Harms, C. A. AU - Levine, J. F. T2 - Journal of Aquatic Animal Health AB - During the fall of 2001 and 2002, Atlantic menhaden Brevoortia tyrannus were collected from several creeks in the Pamlico River, North Carolina, to investigate recent fish kills and ulcerative skin lesions. High skin lesion prevalence (>50%) was associated with the Atlantic menhaden kills in fall 2001, whereas there were no fish kills in fall 2002 and skin lesion prevalence was lower (< or =50%). Indicators of tissue damage (histopathological analyses of gills, heart, liver, intestine, and anterior kidney), body condition (liver somatic index), and immune status (transforming growth factor-beta [TGF-beta] messenger RNA [mRNA] production, hematology, plasma chemistry, and splenosomatic index) were compared between Atlantic menhaden with and without ulcerative skin lesions in fall. Atlantic menhaden with ulcerative skin lesions had significantly higher liver somatic indices, neutrophil and monocyte percentages, and splenic mononuclear cell TGF-beta mRNA levels than did fish without lesions. Hematocrit values, plasma protein, and Ca concentrations were significantly lower in fish with ulcerative skin lesions than in those without. The indicators used in this study at multiple levels of biological organization have provided valuable baseline data for understanding the health status of lesioned and nonlesioned Atlantic menhaden in the Pamlico River. DA - 2007/12// PY - 2007/12// DO - 10.1577/H06-018.1 VL - 19 IS - 4 SP - 205-214 J2 - Journal of Aquatic Animal Health LA - en OP - SN - 0899-7659 1548-8667 UR - http://dx.doi.org/10.1577/H06-018.1 DB - Crossref ER - TY - JOUR TI - Carbon and nitrogen metabolism in the seagrass, Zostera marina L.: Environmental control of enzymes involved in carbon allocation and nitrogen assimilation AU - Touchette, Brant W. AU - Burkholder, JoAnn M. T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - This study experimentally examined influences of environmental variables on the activities of key enzymes involved in carbon and nitrogen metabolism of the submersed marine angiosperm, Zostera marina L. Nitrate reductase activity in leaf tissue was correlated with both water-column nitrate concentrations and leaf sucrose levels. Under elevated nitrate, shoot nitrate reductase activity increased in both light and dark periods if carbohydrate reserves were available. When water-column nitrate was low, glutamine synthetase activity in leaf tissue increased with environmental ammonium. In contrast, glutamine synthetase activity in belowground tissues was statistically related to both nitrate and temperature. At the optimal growth temperature for this species (ca. 25 °C), increased water-column nitrate promoted an increase in glutamine synthetase activity of belowground tissues. As temperatures diverged from the optimum, this nitrate effect on glutamine synthetase was no longer evident. Activities of both sucrose synthase and sucrose-P synthase were directly correlated with temperature. Sucrose-P synthase activity also was correlated with salinity, and sucrose synthase activity was statistically related to tissue ammonium. Overall, the enzymatic responses that were observed indicate a tight coupling between carbon and nitrogen metabolism that is strongly influenced by prevailing environmental conditions, especially temperature, salinity, and environmental nutrient levels. DA - 2007/11/9/ PY - 2007/11/9/ DO - 10.1016/j.jembe.2007.05.034 VL - 350 IS - 1-2 SP - 216-233 SN - 0022-0981 KW - carbon KW - glutamine synthetase KW - nitrate reductase KW - nitrogen KW - sucrose synthase KW - sucrose-P synthase KW - Zostera marina ER - TY - JOUR TI - C-14 groundwater age and the importance of chemical fluxes across aquifer boundaries in confined cretaceous aquifers of North Carolina, USA AU - Kennedy, Casey D. AU - Genereux, David P. T2 - RADIOCARBON AB - Radiocarbon activity, He concentrations, and other geochemical parameters were measured in groundwater from the confined Black Creek (BC) and Upper Cape Fear (UCF) aquifers in the Coastal Plain of North Carolina. 14 C ages adjusted for geochemical and diffusion effects ranged from 400 to 21,900 BP in the BC, and 13,400 to 26,000 BP in the underlying UCF; ages increased coastward in both aquifers. Long-term average linear groundwater velocity is about 2.5 m/yr for the BC, and somewhat larger for the UCF. Aquifer-aquitard exchange is an important influence on the DIC concentration, 14 C activity, and estimated age of aquifer groundwater. Accounting for this exchange in 14 C age calculations places the groundwater samples with the lowest estimated recharge temperatures nearest in time to the last glacial maximum. Traditional geochemical correction models that do not account for aquifer-aquitard exchange significantly overestimate groundwater age. He concentration in groundwater varies with both age and stratigraphic position. Dissolved He data provide strong evidence of upward vertical He transport through the study aquifers; data from the UCF are broadly consistent with the pattern expected for a confined aquifer receiving a concentrated, localized He flux from below (based on a previously published model for this situation), in this case most likely from crystalline bedrock. He has potential as an indicator of groundwater age in the study aquifers, if interpreted within an appropriate analytical framework that includes the observed strong vertical transport. δ 18 O in the oldest groundwater is enriched (relative to modern groundwater) by 1 to 1.2‰, the opposite of the δ 18 O depletion found in many old groundwaters but consistent with the enrichment found in groundwater in this age range in Georgia and Florida. DA - 2007/// PY - 2007/// DO - 10.1017/s0033822200043101 VL - 49 IS - 3 SP - 1181-1203 SN - 1945-5755 ER - TY - JOUR TI - Stable isotope analyses (delta N-15 and delta C-13) of the trophic relationships of Callinectes sapidus in two north Carolina estuaries AU - Bucci, J. P. AU - Showers, W. J. AU - Rebach, S. AU - DeMaster, D. AU - Genna, B. T2 - ESTUARIES AND COASTS DA - 2007/12// PY - 2007/12// DO - 10.1007/BF02841395 VL - 30 IS - 6 SP - 1049-1059 SN - 1559-2731 ER - TY - JOUR TI - Role of isoprene in secondary organic aerosol formation on a regional scale AU - Zhang, Yang AU - Huang, Jian-Ping AU - Henze, Daven K. AU - Seinfeld, John H. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - The role of isoprene as a source of secondary organic aerosol (SOA) is studied using laboratory‐derived SOA yields and the U.S. Environmental Protection Agency regional‐scale Community Multiscale Air Quality (CMAQ) modeling system over a domain comprising the contiguous United States, southern Canada, and northern Mexico. Isoprene is predicted to be a significant source of biogenic SOA, leading to increases up to 3.8 μ g m −3 in the planetary boundary layer (PBL, defined as 0–2.85 km) and 0.44 μ g m −3 in the free troposphere over that in the absence of isoprene. While the addition of isoprene to the class of SOA‐forming organics in CMAQ increases appreciably predicted fine‐particle organic carbon (OC 2.5 ) in the eastern and southeastern U.S., total OC 2.5 is still underpredicted in these regions. SOA formation is highly sensitive to the value of the enthalpy of vaporization of the SOA. The role of isoprene SOA is examined in a sensitivity study at values of 42 and 156 kJ mol −1 ; both are commonly used in 3‐D aerosol models. Prediction of ambient levels of SOA in atmospheric models remains a challenging problem because of the importance of emissions inventories for SOA‐forming organics, representation of gas phase atmospheric chemistry leading to semivolatile products, and treatment of the physics and chemistry of aerosol formation and removal. DA - 2007/10/23/ PY - 2007/10/23/ DO - 10.1029/2007jd008675 VL - 112 IS - D20 SP - SN - 2169-8996 ER - TY - JOUR TI - A five-year climatology of elevated severe convective storms in the united states east of the Rocky Mountains AU - Horgan, Katherine L. AU - Schultz, David M. AU - Hales, John E., Jr. AU - Corfidi, Stephen F. AU - Johns, Robert H. T2 - WEATHER AND FORECASTING AB - Abstract A 5-yr climatology of elevated severe convective storms was constructed for 1983–87 east of the Rocky Mountains. Potential cases were selected by finding severe storm reports on the cold side of surface fronts. Of the 1826 days during the 5-yr period, 1689 (91%) had surface fronts east of the Rockies. Of the 1689 days with surface fronts, 129 (8%) were associated with elevated severe storm cases. Of the 1066 severe storm reports associated with the 129 elevated severe storm cases, 624 (59%) were hail reports, 396 (37%) were wind reports, and 46 (4%) were tornado reports. A maximum of elevated severe storm cases occurred in May with a secondary maximum in September. Elevated severe storm cases vary geographically throughout the year, with a maximum over the south-central United States in winter to a central and eastern U.S. maximum in spring and summer. A diurnal maximum of elevated severe storm cases occurred at 2100 UTC, which coincided with the diurnal maximum of hail reports. The wind reports had a broad maximum during the daytime. Because the forecasting of hail from elevated storms typically does not pose as significant a forecast challenge as severe wind for forecasters and tornadoes from elevated storms are relatively uncommon, this study focuses on the occurrence of severe wind from elevated storms. Elevated severe storm cases that produce only severe wind reports occurred roughly 5 times a year. To examine the environments associated with cases that produced severe winds only, five cases were examined in more detail. Common elements among the five cases included elevated convective available potential energy, weak surface easterlies, and shallow near-surface stable layers (less than 100 hPa thick). DA - 2007/10// PY - 2007/10// DO - 10.1175/WAF1032.1 VL - 22 IS - 5 SP - 1031-1044 SN - 1520-0434 ER - TY - JOUR TI - The three-dimensional structure and kinematics of drizzling stratocumulus AU - Comstock, Kimberly K. AU - Yuter, Sandra E. AU - Wood, Robert AU - Bretherton, Christopher S. T2 - MONTHLY WEATHER REVIEW AB - Abstract Drizzling marine stratocumulus are examined using observations from the 2001 East Pacific Investigation of Climate Stratocumulus (EPIC Sc) field experiment. This study uses a unique combination of satellite and shipborne Doppler radar data including both horizontal and vertical cross sections through drizzle cells. Stratocumulus cloud structure was classified as closed cellular, open cellular, or unclassifiable using infrared satellite images. Distributions of drizzle cell structure, size, and intensity are similar among the cloud-structure categories, though the open-cellular distributions are shifted toward higher values. Stronger and larger drizzle cells preferentially occur when the cloud field is broken (open-cellular and unclassifiable categories). Satellite observations of cloud structure may be useful to indicate the most likely distribution of rain rates associated with a set of scenes, but infrared data alone are not sufficient to develop routine precipitation retrievals for marine stratocumulus. Individual drizzle cells about 2–20 km across usually showed precipitation growth within the cloud layer and evaporation below, divergence near echo top, and convergence below cloud base. Diverging flow near the surface was also observed beneath heavily precipitating drizzle cells. As the cloud field transitioned from a closed to an open-cellular cloud structure, shipborne radar revealed prolific development of small drizzle cells (&lt;10 km2) that exceeded by over 5 times the number of total cells in either the preceding closed-cellular or following open-cellular periods. Peak area-average rain rates lagged by a few hours the peak in total number of drizzle cells. Based on observations from EPIC Sc, the highest stratocumulus rain rates are more likely to occur near the boundary between closed and open-cellular cloud structures. DA - 2007/11// PY - 2007/11// DO - 10.1175/2007MWR1944.1 VL - 135 IS - 11 SP - 3767-3784 SN - 1520-0493 ER - TY - JOUR TI - Short-term changes in seafloor character due to flood-derived hyperpycnal discharge: Typhoon Mindulle, Taiwan, July 2004 AU - Milliman, J. D. AU - Lin, S. W. AU - Kao, S. J. AU - Liu, J. P. AU - Liu, C. S. AU - Chiu, J. K. AU - Lin, Y. C. T2 - Geology (Boulder, Colo.) DA - 2007/// PY - 2007/// VL - 35 IS - 9 SP - 779-782 ER - TY - JOUR TI - Empirical analysis of intraseasonal climate variability over the greater horn of Africa AU - Bowden, Jared H. AU - Semazzi, Fredrick H. M. T2 - JOURNAL OF CLIMATE AB - Abstract This study examines the intraseasonal climate variability over the Greater Horn of Africa (GHA) during the rainy season of October–December (OND). The investigation is primarily based on empirical orthogonal function (EOF) analysis of the pentad Climate Prediction Center Merged Analysis of Precipitation (CMAP) data for the period 1979–2001. The EOF analysis reveals two dominant modes of intraseasonal variability for the OND season: mixed El Niño–Southern Oscillation–Indian Ocean dipole (ENSO-IOD) and a decadal mode. The leading mode is associated with ENSO–IOD covariability. Case studies of several intraseasonal ENSO–IOD events within the recent decades indicate that during the warm (positive) events pentad rainfall is consistently above normal during the entire season despite fluctuations between pentads. However, case study analyses of negative ENSO–IOD events show that the negative cases are not mirror images of the warm events. The negative events exhibit pronounced wet and dry spells superimposed on the consistent dry anomaly background conditions. There is no large signal regarding the onset for either case, but the withdrawal of the positive (negative) events is anomalously wet (dry). The second mode of variability is associated with a decadal shift in the rainfall with the northern (southern) GHA becoming wetter (drier) in the recent decade. The decadal change in individual pentads can be quite different across the season and has a tendency to manifest itself through extreme events. The analysis underscores the need to exercise caution when applying seasonal-average-based statistics to infer the long-term behavior on subseasonal time scales. Additional analyses further confirm the decadal rainfall shift using four different rainfall datasets. Averaging the datasets to help aid in removing bias of individual datasets shows that, on average, northern (southern) portions of GHA are 29% (19%) wetter (drier) in the recent decade. DA - 2007/12// PY - 2007/12// DO - 10.1175/2007JCLI1587.1 VL - 20 IS - 23 SP - 5715-5731 SN - 1520-0442 UR - http://dx.doi.org/10.1175/2007jcli1587.1 ER - TY - JOUR TI - Convective episodes in the East-Central United States AU - Parker, Matthew D. AU - Ahijevych, David A. T2 - MONTHLY WEATHER REVIEW AB - Abstract Nine years of composited radar data are investigated to assess the presence of organized convective episodes in the east-central United States. In the eastern United States, the afternoon maximum in thunderstorms is ubiquitous over land. However, after removing this principal diurnal peak from the radar data, the presence and motion of organized convective systems becomes apparent in both temporally averaged fields and in the statistics of convective episodes identified by an objective algorithm. Convective echoes are diurnally maximized over the Appalachian chain, and are repeatedly observed to move toward the east. Partly as a result of this, the daily maximum in storms is delayed over the Piedmont and coastal plain relative to the Appalachian Mountains and the Atlantic coast. During the 9 yr studied, the objective algorithm identified 2128 total convective episodes (236 yr−1), with several recurring behaviors. Many systems developed over the elevated terrain during the afternoon and moved eastward, often to the coastline and even offshore. In addition, numerous systems formed to the west of the Appalachian Mountains and moved into and across the eastern U.S. study domain. In particular, many nocturnal convective systems from the central United States entered the western side of the study domain, frequently arriving at the eastern mountains around the next day’s afternoon maximum in storm frequency. A fraction of such well-timed systems succeeded in crossing the Appalachians and continuing across the Piedmont and coastal plain. Convective episodes were most frequent during the high-instability, low-shear months of summer, which dominate the year-round statistics. Even so, an important result is that the episodes still occurred almost exclusively in above-average vertical wind shear. Despite the overall dominance of the diurnal cycle, the data show that adequate shear in the region frequently leads to long-lived convective episodes with mesoscale organization. DA - 2007/11// PY - 2007/11// DO - 10.1175/2007MWR2098.1 VL - 135 IS - 11 SP - 3707-3727 SN - 0027-0644 ER - TY - JOUR TI - Constraining biogenic silica dissolution in marine sediments: A comparison between diagenetic models and experimental dissolution rates AU - Khalil, K. AU - Rabouille, C. AU - Gallinari, M. AU - Soetaert, K. AU - DeMaster, D. J. AU - Ragueneau, O. T2 - MARINE CHEMISTRY AB - The processes controlling preservation and recycling of particulate biogenic silica in sediments must be understood in order to calculate oceanic silica mass balances. The new contribution of this work is the coupled use of advanced models including reprecipitation and different phases of biogenic silica with different dissolution characteristics as well as new data sets concerning experimental dissolution rates of marine particles and sediment opal obtained in flow-through reactors. We have used three models representing early diagenesis of biogenic silica in sediments that calculate the vertical distributions of dissolved silicate and solid silica in sediments. Model 1 contains one type of biogenic silica and the dissolution rate is constant, whereas model 2 contains a variable dissolution rate constant with sediment depth (representing aging) and one type of biogenic silica. Model 3 incorporates aging by describing two types of biogenic silica that differ by their dissolution properties. An explicit term of reprecipitation is incorporated into the three models. The distributions of dissolved silicate and solid silica predicted by steady-state calculations are compared to 4 observed data sets, from the Southern Ocean, the Equatorial Pacific and the North Atlantic, covering a wide range of sediment compositions, from opal-rich to opal-poor sediments. After adjustment of the critical parameters (the apparent silica dissolution rate constants, the biogenic silica flux deposited at the sediment–water interface and the reprecipitation rate), the second and third models provide good agreements between predicted and measured dissolved Si and solid silica profiles for each data set, except for the second model in the Equatorial Pacific. However, a large discrepancy between the experimentally derived dissolution rate constants and those calculated by the models is observed at all sites at depth in the sediment, suggesting that either artifacts arise during dissolution experiments such as over-representation of rapidly dissolving silica or variation of dissolution properties during the experimental procedures or the model oversimplifies the processes associated to silica dissolution and alumino-silicate reprecipitation and their interaction. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.marchem.2006.12.004 VL - 106 IS - 1-2 SP - 223-238 SN - 1872-7581 KW - silica cycle KW - early diagenesis KW - biogenic silica dissolution KW - reprecipitation KW - North Atlantic KW - Equatorial Pacific KW - Southern Ocean ER - TY - JOUR TI - An abelisauroid (Dinosauria : Theropoda) from the Early Jurassic of the High Atlas Mountains, Morocco, and the radiation of ceratosaurs AU - Allain, Ronan AU - Tykoski, Ronald AU - Aquesbi, Najat AU - Jalil, Nour-Eddine AU - Monbaron, Michel AU - Russel, Dale AU - Taquet, Philippe T2 - JOURNAL OF VERTEBRATE PALEONTOLOGY AB - ABSTRACT The fossil record of abelisauroid carnivorous dinosaurs was previously restricted to Cretaceous sediments of Gondwana and probably Europe. The discovery of an incomplete specimen of a new basal abelisauroid, Berberosaurus liassicus, gen. et sp. nov., is reported from the late Early Jurassic of Moroccan High Atlas Mountains. Phylogenetic analysis recovers Ceratosauroidea and Coelophysoidea as sister lineages within Ceratosauria, and Berberosaurus as a basal abelisauroid. Berberosaurus is the oldest known abelisauroid and extends the first appearance datum of this lineage by about 50 million years. The taxon bridges temporal, morphological, and phylogenetic gaps that have hitherto separated Triassic to Early Jurassic coelophysoids from Late Jurassic through Cretaceous ceratosauroids. The discovery of an African abelisauroid in the Early Jurassic confirms at least a Gondwanan distribution of this group long before the Cretaceous. DA - 2007/9/12/ PY - 2007/9/12/ DO - 10.1671/0272-4634(2007)27[610:AADTFT]2.0.CO;2 VL - 27 IS - 3 SP - 610-624 SN - 1937-2809 ER - TY - JOUR TI - A comparison of two exposure systems to apply malathion to Lumbricus terrestris L AU - Henson-Ramsey, H. AU - Kennedy-Stoskopf, S. AU - Levine, J. AU - Shea, D. AU - Taylor, S. K. AU - Stoskopf, M. K. T2 - BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY DA - 2007/6// PY - 2007/6// DO - 10.1007/s00128-007-9194-7 VL - 78 IS - 6 SP - 427-431 SN - 0007-4861 ER - TY - JOUR TI - A comparison of photoresponse among ten different Karenia brevis (Dinophyceae) isolates AU - Schaeffer, Blake A. AU - Kamykowski, Daniel AU - McKay, Laurie AU - Sinclair, Geoff AU - Milligan, Edward J. T2 - JOURNAL OF PHYCOLOGY AB - Many laboratories have solely used the Wilson isolate to physiologically characterize the harmful algal bloom (HAB) dinoflagellate Karenia brevis (C. C. Davis) G. Hansen et Moestrup. However, analysis of one isolate may lead to misinterpretations when extrapolating measurements to field populations. In this study, pulse‐amplitude‐modulated chlorophyll fluorometer (PAM‐FL) relative electron transport rate (ETR), F v / F m , and chl were compared with traditional techniques, such as 14 C photosynthesis versus irradiance (P–E) curves, DCMU [3‐(3′,4′‐dichlorophenyl)‐1,1‐dimethyl urea] F v / F m , and extracted chl. The DCMU and PAM‐FL values of F v / F m ( r 2 = 0.51) and chl ( r 2 = 0.58) were in good agreement. There was no correlation between 14 C and PAM‐FL α, P max , and β parameters because PAM‐FL ETR was only a relative measurement. The PAM‐FL techniques were then used to investigate P–E curves, quantum yield of PSII ( F v / F m ), and chl from 10 K. brevis isolates to determine whether one or all isolates would better represent the species. Comparisons were made with a radial photosynthetron, which allowed for controlled conditions of light and temperature. Isolate α, P max , and β varied between 0.097 and 0.204 μmol e − · m −2 · s −1 · (μmol quanta · m −2 · s −1 ) −1 , 80.41 and 241 μmol e − · m −2 · s −1 , and 0.005 and 0.160 μmol e − · m −2 · s −1 · (μmol quanta · m −2 · s −1 ) −1 , respectively. Either carbon limitation and/or bacterial negative feedback were implicated as the cause of the P–E parameter variability. Furthermore, these results directly contradicted some literature suggestions that K. brevis is a low‐light‐adapted dinoflagellate. Results showed that K. brevis was more than capable of utilizing and surviving in light conditions that may be present on cloudless days off Florida. DA - 2007/8// PY - 2007/8// DO - 10.1111/j.1529-8817.2007.00377.x VL - 43 IS - 4 SP - 702-714 SN - 1529-8817 KW - carbon KW - cell division rate KW - culture KW - dinoflagellate KW - F-v/F-m KW - Karenia brevis KW - P-E curve KW - photoinhibition ER - TY - JOUR TI - Water mass seasonal variability in the Galapagos archipelago AU - Sweet, W. V. AU - Morrison, J. M. AU - Kamykowski, D. AU - Schaeffer, B. A. AU - Banks, S. AU - McCulloch, A. T2 - DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS AB - Three hydrographic surveys were conducted within the Galápagos Archipelago during 2005–2006. The surveys captured the surface properties (<80 m) near the extremes and midpoint of the annual cycle of the mean sea surface temperature (SST) and winds. A cooler SST occurs in boreal summer and fall as the southeast trades strengthen. Current data at 110°W show that this coincides with the Equatorial Undercurrent (EUC) becoming weaker and deeper below a strengthening westward South Equatorial Current (SEC). Opposite conditions are generally found in the spring. Meanwhile, the sea surface salinity (SSS) freshens in late winter/spring when the archipelago receives large rainfalls as the Intertropical Convergence Zone (ITCZ) shifts southward, or in late fall when receiving large influxes from the North Equatorial Countercurrent (NECC). As a result, Tropical Surface Waters (TSW) with salinity (S) <34 fill the archipelago from the late fall through early spring. The SSS becomes saltiest in late spring/early summer as the EUC strengthens, resulting in Equatorial Surface Waters (ESW), S>34, throughout the archipelago. Equatorial Surface Waters are present west of Isabela, where the EUC upwells as it interacts with the Galápagos platform. They also are found east of the archipelago in the cold tongue, which extends westward from South America, and therefore may be advected by the SEC into the archipelago. The upwelling west of Isabela creates a consistently shallow 20 °C isotherm (thermocline), which remains elevated across the archipelago. Linear extrapolation of the thermocline depth along the equator from 110 to 95°W gives a good approximation of the thermocline depth within the archipelago from 92 to 89°W. DA - 2007/12// PY - 2007/12// DO - 10.1016/j.dsr.2007.09.009 VL - 54 IS - 12 SP - 2023-2035 SN - 1879-0119 KW - Galapagos KW - eastern Pacific KW - equatorial undercurrent KW - upwelling KW - water masses ER - TY - JOUR TI - Modeling of the Cape Fear River Estuary plume AU - Xia, Meng AU - Xie, Lian AU - Pietrafesa, Leonard J. T2 - ESTUARIES AND COASTS DA - 2007/8// PY - 2007/8// DO - 10.1007/BF02841966 VL - 30 IS - 4 SP - 698-709 SN - 1559-2731 ER - TY - JOUR TI - Exposure of Unionid Mussels to Electric Current: Assessing Risks Associated with Electrofishing AU - Holliman, F. Michael AU - Kwak, Thomas J. AU - Cope, W. Gregory AU - Levine, Jay F. T2 - Transactions of the American Fisheries Society AB - Abstract Electric current is routinely applied in freshwater for scientific sampling of fish populations (i.e., electrofishing). Freshwater mussels (families Margaritiferidae and Unionidae) are distributed worldwide, but their recent declines in diversity and abundance constitute an imperilment of global significance. Freshwater mussels are not targeted for capture by electrofishing, and any exposure to electric current is unintentional. The effects of electric shock are not fully understood for mussels but could disrupt vital physiological processes and represent an additional threat to their survival. In a controlled laboratory environment, we examined the consequences of exposure to two typical electrofishing currents, 60‐Hz pulsed DC and 60‐Hz AC, for the survival of adult and early life stages of three unionid species; we included fish as a quality control measure. The outcomes suggest that electrical exposure associated with typical electrofishing poses little direct risk to freshwater mussels. That is, adult mussel survival and righting behaviors (indicators of sublethal stress) were not adversely affected by electrical exposure. Glochidia (larvae that attach to and become parasites on fish gills or fins) showed minimal immediate reduction in viability after exposure. Metamorphosis from glochidia to free‐living juvenile mussels was not impaired after electric current simulated capture‐prone behaviors (stunning) in infested host fish. In addition, the short‐term survival of juvenile mussels was not adversely influenced by exposure to electric current. Any minimal risk to imperiled mussels must be weighed at the population level against the benefits gained by using the gear for scientific sampling of fish in the same waters. However, scientists sampling fish by electrofishing should be aware of mussel reproductive periods and processes in order to minimize the harmful effects to host fish, especially in areas where mussel conservation is a concern. DA - 2007/11// PY - 2007/11// DO - 10.1577/T07-006.1 VL - 136 IS - 6 SP - 1593-1606 J2 - Transactions of the American Fisheries Society LA - en OP - SN - 0002-8487 1548-8659 UR - http://dx.doi.org/10.1577/T07-006.1 DB - Crossref ER - TY - JOUR TI - Environmental influences on the relationship between juvenile and larval growth of Atlantic croaker Micropogonias undulatus AU - Searcy, Steven P. AU - Eggleston, David B. AU - Hare, Jonathan A. T2 - MARINE ECOLOGY PROGRESS SERIES AB - MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 349:81-88 (2007) - DOI: https://doi.org/10.3354/meps07124 Environmental influences on the relationship between juvenile and larval growth of Atlantic croaker Micropogonias undulatus Steven P. Searcy1,2,*, David B. Eggleston2, Jonathan A. Hare3,4 1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA 2School for Marine Science & Technology, University of Massachusetts Dartmouth, 838 South Rodney French Boulevard, New Bedford, Massachusetts 02744-1221, USA 3NOAA, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, North Carolina 28516-9722, USA 4Present address: NOAA, National Marine Fisheries Service, Northeast Fisheries Science Center, Narragansett Laboratory, 28 Tarzwell Drive, Narragansett, Rhode Island 02882-1199, USA *Present address: New Bedford, MA. Email: ssearcy@umassd.edu ABSTRACT: For marine organisms with bipartite life cycles, there is growing recognition that juvenile traits may be dependent on previous larval history. The potential correlation between juvenile and larval stages is important to recognize, as growth rates in juvenile fish have been proposed to be an indicator of habitat quality. We investigated whether juvenile and larval growth are positively or negatively related using the estuarine-dependent fish Atlantic croaker Micropogonias undulatus as a model species. The relationship between juvenile and larval growth was examined using both a laboratory study, in which fish were held in individual containers with constant water temperature and salinity, and replicated field experiments, which spanned a range of environmental conditions. There was no relationship between juvenile and larval growth rates in the laboratory experiment. However, results from the field study suggest that a positive relationship between juvenile and larval growth was associated with high levels of freshwater runoff that displaced juvenile croaker from nursery areas to downstream habitats, in which they had reduced feeding success. Variability in the correlation between juvenile and larval growth for the 27 cohorts examined (fish hatched during the same 1 wk period) was independently explained by change in salinity (a proxy for freshwater runoff) and feeding ability (percentage of fish with empty stomachs). Future research should recognize the role that variable environments play in our ability to detect the relationship of life-history traits between ontogenetic stages. KEY WORDS: Larval growth · Juvenile growth · Atlantic croaker · Freshwater runoff · Habitat quality Full text in pdf format PreviousNextCite this article as: Searcy SP, Eggleston DB, Hare JA (2007) Environmental influences on the relationship between juvenile and larval growth of Atlantic croaker Micropogonias undulatus. Mar Ecol Prog Ser 349:81-88. https://doi.org/10.3354/meps07124 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 349. Online publication date: November 08, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research. DA - 2007/// PY - 2007/// DO - 10.3354/meps07124 VL - 349 SP - 81-88 SN - 1616-1599 KW - larval growth KW - juvenile growth KW - Atlantic croaker KW - freshwater runoff KW - habitat quality ER - TY - JOUR TI - Dynamics of Jovian atmospheres with applications of nonlinear singular vector method AU - Zhang, Zhiyue AU - Lin, Jing T2 - INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS AB - Abstract Nonlinear singular vectors (NSVs) of a Jovian atmosphere model are obtained numerically in this paper. NSVs are the initial perturbation, whose nonlinear evolution attains the maximal value of the cost function, which is constructed according to the physical problem of interest. The results demonstrate that the motions of Jupiter's atmosphere is relatively stable under some assumptions. Copyright © 2007 John Wiley & Sons, Ltd. DA - 2007/11/20/ PY - 2007/11/20/ DO - 10.1002/fld.1471 VL - 55 IS - 8 SP - 713-721 SN - 0271-2091 KW - nonlinear singular vector KW - finite difference KW - optimization KW - Jupiter KW - Earth ER - TY - JOUR TI - A study of the variation of urban mixed layer heights AU - Simpson, Matthew AU - Raman, Sethu AU - Lundquist, Julie K. AU - Leach, Martin T2 - ATMOSPHERIC ENVIRONMENT AB - The AERMET model is used to estimate hourly mixing heights during the Joint URBAN (2003) experiment in Oklahoma City, Oklahoma. AERMET is a simple 2-D model that requires only routine meteorological observations and an early morning atmospheric sounding to estimate convective boundary layer (CBL) growth. Estimated mixing heights are compared with observed mixing heights measured during Joint URBAN 2003. Observed CBL heights are derived from profiler data using a peak signal-to-noise ratio method. The method of deriving mixing heights from profiler data is validated using daily atmospheric sounding data. Estimated mixing heights using AERMET show good agreement with observations on days of varying temperature and cloud cover. AERMET was able to estimate the rapid boundary layer growth observed in the late morning and early afternoon hours during highly convective conditions. CBL heights of over 3000 m are observed in sounding data during the late afternoon. Estimated CBL heights of over 3000 m during the late afternoon agreed well with observations from the sounding and profiler data. DA - 2007/10// PY - 2007/10// DO - 10.1016/j.atmosenv.2006.08.029 VL - 41 IS - 33 SP - 6923-6930 SN - 1352-2310 KW - AERMET KW - convective boundary layer KW - profiler KW - joint URBAN (2003) KW - signal-to-noise ratio ER - TY - JOUR TI - Internal architecture and mobility of tidal sand ridges in the East China Sea AU - Liu, Zhenxia AU - Berné, Serge AU - Saito, Yoshiki AU - Yu, Hua AU - Trentesaux, Alain AU - Uehara, Katsuto AU - Yin, Ping AU - Paul Liu, J. AU - Li, Chaoxing AU - Hu, Guanghai AU - Wang, Xiangqin T2 - Continental Shelf Research AB - On the basis of bathymetric and seismic data and data from piston cores collected by the Chinese–French marine geology and geophysics investigation of 1996, we discuss the internal architecture and mobility of tidal sand ridges in the East China Sea (ECS). We characterized the sand ridges on the middle to outer shelf of the ECS as tide-dominated sand ridges with southwest dipping beds, indicating that the regional net sediment transport is toward the southwest. As the sand ridges gradually migrate toward the southwest, new sand ridges are continually replacing old ones, and several generations of sand ridges have developed in the study area. High-resolution seismic data, acoustic Doppler current profiler data, and two 14C-dated piston cores, DGKS9614 and DGKS9612—from a sand ridge swale and crest, respectively—show that these sand ridges, which are at water depths of 90–100 m, have been migrating for the last ca. 2–3 kyr at least, though these ridges have previously been interpreted as moribund or relict. Sequence stratigraphic interpretation of seismic profiles and core data show that tidal ridges in the ECS evolved from muddier sand ridges formed during the last transgression to sandier shelf sand ridges in response to the shoreline retreat, which resulted in a decrease of riverine muddy sediments and recycling of sandy materials by tidal currents. Most active sand ridge formation occurred during the last transgression, but the present sand ridges on the middle to outer shelf are still being influenced by the modern hydrodynamics. Therefore, these sand ridges on the ECS shelf should be referred to as “quasi-active sand ridges” rather than as moribund or relict sand ridges. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.csr.2007.03.002 VL - 27 IS - 13 SP - 1820-1834 J2 - Continental Shelf Research LA - en OP - SN - 0278-4343 UR - http://dx.doi.org/10.1016/j.csr.2007.03.002 DB - Crossref KW - tidal sand ridge KW - internal architecture KW - mobility KW - East China Sea KW - ridge evolution KW - transgression ER - TY - JOUR TI - Flux and fate of Yangtze River sediment delivered to the East China Sea AU - Liu, J.P. AU - Xu, K.H. AU - Li, A.C. AU - Milliman, J.D. AU - Velozzi, D.M. AU - Xiao, S.B. AU - Yang, Z.S. T2 - Geomorphology AB - Numerous cores and dating show the Yangtze River has accumulated about 1.16 × 1012 t sediment in its delta plain and proximal subaqueous delta during Holocene. High-resolution seismic profiling and coring in the southern East China Sea during 2003 and 2004 cruises has revealed an elongated (∼ 800 km) distal subaqueous mud wedge extending from the Yangtze River mouth southward off the Zhejiang and Fujian coasts into the Taiwan Strait. Overlying what appears to be a transgressive sand layer, this distal clinoform thins offshore, from ∼ 40 m thickness between the 20 and 30 m water depth to < 1–2 m between 60 and 90 m water depth, corresponding to an across shelf distance of less than 100 km. Total volume of this distal mud wedge is about 4.5 × 1011 m3, equivalent to ∼ 5.4 × 1011 t of sediment. Most of the sediment in this mud wedge comes from the Yangtze River, with some input presumably coming from local smaller rivers. Thus, the total Yangtze-derived sediments accumulated in its deltaic system and East China Sea inner shelf have amounted to about 1.7 × 1012 t. Preliminary analyses suggest this longshore and across-shelf transported clinoform mainly formed in the past 7000 yrs after postglacial sea level reached its mid-Holocene highstand, and after re-intensification of the Chinese longshore current system. Sedimentation accumulation apparently increased around 2000 yrs BP, reflecting the evolution of the Yangtze estuary and increased land erosion due to human activities, such as farming and deforestation. The southward-flowing China Coastal Current, the northward-flowing Taiwan Warm Current, and the Kuroshio Current appear to have played critical roles in transporting and trapping most of Yangtze-derived materials in the inner shelf, and hence preventing the sediment escape into the deep ocean. DA - 2007/3// PY - 2007/3// DO - 10.1016/j.geomorph.2006.03.023 VL - 85 IS - 3-4 SP - 208-224 J2 - Geomorphology LA - en OP - SN - 0169-555X UR - http://dx.doi.org/10.1016/j.geomorph.2006.03.023 DB - Crossref KW - East China Sea KW - Yangtze River KW - clinoform KW - delta KW - mud wedge KW - sea level ER - TY - JOUR TI - The effect of upstream convection on downstream precipitation AU - Mahoney, Kelly M. AU - Lackmann, Gary M. T2 - WEATHER AND FORECASTING AB - Abstract Operational forecasters in the southeast and mid-Atlantic regions of the United States have noted a positive quantitative precipitation forecast (QPF) bias in numerical weather prediction (NWP) model forecasts downstream of some organized, cold-season convective systems. Examination of cold-season cases in which model QPF guidance exhibited large errors allowed identification of two representative cases for detailed analysis. The goals of the case study analyses are to (i) identify physical mechanisms through which the upstream convection (UC) alters downstream precipitation amounts, (ii) determine why operational models are challenged to provide accurate guidance in these situations, and (iii) suggest future research directions that would improve model forecasts in these situations and allow forecasters to better anticipate such events. Two primary scenarios are identified during which downstream precipitation is altered in the presence of UC for the study region: (i) a fast-moving convective (FC) scenario in which organized convective systems oriented parallel to the lower-tropospheric flow are progressive relative to the parent synoptic system, and appear to disrupt poleward moisture transport, and (ii) a situation characterized by slower-moving convection (SC) relative to the parent system. Analysis of a representative FC case indicated that moisture consumption, stabilization via convective overturning, and modification of the low-level flow to a more westerly direction in the postconvective environment all appear to contribute to the reduction of downstream precipitation. In the FC case, operational Eta Model forecasts moved the organized UC too slowly, resulting in an overestimate of downstream moisture transport. A 4-km explicit convection model forecast from the Weather Research and Forecasting model produced a faster-moving upstream convective system and improved downstream QPF. In contrast to the FC event, latent heat release in the primary rainband is shown to enhance the low-level jet ahead of the convection in the SC case, thereby increasing moisture transport into the downstream region. A negative model QPF bias was observed in Eta Model forecasts for the SC event. Suggestions are made for precipitation forecasting in UC situations, and implications for NWP model configuration are discussed. DA - 2007/4// PY - 2007/4// DO - 10.1175/WAF986.1 VL - 22 IS - 2 SP - 255-277 SN - 1520-0434 ER - TY - JOUR TI - The effect of amlodipine and the combination of amlodipine and enalapril on the renin-angiotensin-aldosterone system in the dog AU - Atkins, C. E. AU - Rausch, W. P. AU - Gardner, S. Y. AU - Defrancesco, T. C. AU - Keene, B. W. AU - Levine, J. F. T2 - Journal of Veterinary Pharmacology and Therapeutics AB - Excessive aldosterone secretion is detrimental to the heart, vessels and kidneys, contributing to hypertension and the signs and progression of heart failure. Aldosterone secretion, abnormally elevated in heart failure and hypertension, can be blunted with angiotensin‐converting enzyme inhibitors. Amlodipine, used to treat hypertension and heart failure, was hypothesized to activate the renin‐angiotensin‐aldosterone system (RAAS). A study was conducted with six normal adult male beagle dogs. Each dog received amlodipine (0.57 mg/kg b.i.d.) for 6 days, followed by amlodipine (0.57 mg/kg b.i.d.) and enalapril (0.57 mg/kg b.i.d.) for 4 days. Blood pressure, heart rate, serum chemistries and urinary aldosterone excretion, as a measure of RAAS activation, were compared with baseline values. Blood pressure fell by approximately 7% with amlodipine ( P = 0.05) and a further 7% with the combination of amlodipine and enalapril ( P < 0.01). Blood urea nitrogen increased with the combination ( P < 0.05) but only one dog became mildly azotemic. Renin‐angiotensin‐aldosterone system activation, based on 24 h urinary aldosterone excretion and by aldosterone:creatinine ratio was increased by approximately threefold ( P < 0.05) with amlodipine administration. This effect was blunted by enalapril, such that aldosterone excretion was no longer different from that observed under control conditions, although values for 24‐h aldosterone excretion did not return to pretreament levels. DA - 2007/10// PY - 2007/10// DO - 10.1111/j.1365-2885.2007.00894.x VL - 30 IS - 5 SP - 394-400 J2 - J Vet Pharmacol Ther LA - en OP - SN - 0140-7783 1365-2885 UR - http://dx.doi.org/10.1111/j.1365-2885.2007.00894.x DB - Crossref ER - TY - JOUR TI - Stepwise decreases of the Huanghe (Yellow River) sediment load (1950–2005): Impacts of climate change and human activities AU - Wang, Houjie AU - Yang, Zuosheng AU - Saito, Yoshiki AU - Liu, J. Paul AU - Sun, Xiaoxia AU - Wang, Yan T2 - Global and Planetary Change AB - The sediment load delivered from the Huanghe (Yellow River) to the sea has decreased sharply to 0.15 × 109 metric tons per year (0.15 Gt/yr) between 2000 and 2005, and now represents only 14% of the widely cited estimate of 1.08 Gt/yr. The river seems to be reverting to the pristine levels characteristic of the middle Holocene, prior to human intervention. Datasets from 1950 to 2005 from four key gauging stations in the main stream reveal distinct stepwise decreases in sediment load, which are attributed to both natural and anthropogenic impacts over the past 56 yr. Completions of two reservoirs, Liujiaxia (1968) and Longyangxia (1985), in the upper reaches of the river and their joint operations have resulted in stepwise decreases in sediment load coming from the upper reaches. Effective soil conservation practices in the middle reaches since the late 1970s, combined with the operation of the Sanmenxia and Xiaolangdi reservoirs, have also caused stepwise decreases in sediment load at Huayuankou in the middle reaches, but the decrease differs from that observed in the upper reaches. Decrease in precipitation is responsible for 30% of the decrease in sediment load at Huayuankou, while the remaining 70% is ascribed to human activities in the river basin, of which soil conservation practices contribute 40% to the total decrease. Sediment retention within reservoirs accounts for 20% of the total sediment load decrease, although there was notable sediment retention within the Xiaolangdi reservoir from 2000 to 2005. The remaining 10% of the decrease in sediment load is a result of the operation of reservoirs in the upper reaches. In the lower reaches, 20% of the sediment passing Huayuankou has been lost as a result of channel deposition and water abstraction. Soil conservation practices and the operation of reservoirs have lowered the content of coarser sediment (D > 0.05 mm) at Huayuankou, and reduced channel deposition in the lower reaches. In contrast, sediment loss owing to water abstraction in the lower reaches has increased considerably as water consumption for agricultural needs has increased. Therefore, the combined effects of climate change and human activities in the upper, middle, and lower reaches have resulted in stepwise decreases in the sediment load delivered from the Huanghe to the sea. The Huanghe provides an excellent example of the altered river systems impacted by climate change and extensive human activities over the past 56 yr. Further dramatic decreases in sediment load and water discharge in the Huanghe will trigger profound geological, morphological, ecological, and biogeochemical responses in the estuary, delta, and coastal sea. DA - 2007/6// PY - 2007/6// DO - 10.1016/j.gloplacha.2007.01.003 VL - 57 IS - 3-4 SP - 331-354 J2 - Global and Planetary Change LA - en OP - SN - 0921-8181 UR - http://dx.doi.org/10.1016/j.gloplacha.2007.01.003 DB - Crossref KW - Huanghe (Yellow River) KW - stepwise decrease KW - sediment load KW - climate change KW - human activity KW - dam and reservoir ER - TY - JOUR TI - Precipitation distribution associated with landfalling tropical cyclones over the eastern United States AU - Atallah, Eyad AU - Bosart, Lance F. AU - Aiyyer, Anantha R. T2 - MONTHLY WEATHER REVIEW AB - Abstract Tropical cyclones (TCs) making landfall over the United States are examined by separating those associated with precipitation predominantly left of their tracks from those with the same to the right of their tracks. Composites of atmospheric variables for these two TC categories are performed and analyzed using potential vorticity (PV) and quasigeostrophic (QG) frameworks. Dynamical signatures are retrieved from these composites to help understand the evolution of precipitation in these storms. Results indicate that a left of track precipitation distribution (e.g., Floyd 1999) is characteristic of TCs undergoing extratropical transition (ET). In these cases, a positively tilted midlatitude trough approaches the TC from the northwest, shifting precipitation to the north-northwest of the TC. Potential vorticity redistribution through diabatic heating leads to enhanced ridging over and downstream of the TC, resulting in an increase in the cyclonic advection of vorticity by the thermal wind over the transitioning TC. A right of track precipitation distribution is characteristic of TCs interacting with a downstream ridge (e.g., David 1979). When the downstream ridge amplifies in response to TC-induced diabatic heating ahead of a weak midlatitude trough, the PV gradient between the TC and the downstream ridge is accentuated, producing a region of enhanced positive PV advection (and cyclonic vorticity advection by the thermal wind) over the TC. The diabatic enhancement of the downstream ridge is instrumental in the redistribution of precipitation about the transitioning TCs in both cases and poses a significant forecast challenge. DA - 2007/6// PY - 2007/6// DO - 10.1175/MWR3382.1 VL - 135 IS - 6 SP - 2185-2206 SN - 0027-0644 ER - TY - JOUR TI - Phylogenetic analysis of spring virema of carp virus reveals distinct subgroups with common origins for recent isolates in North America and the UK AU - Miller, O. AU - Fuller, F. J. AU - Gebreyes, W. A. AU - Lewbart, G. A. AU - Shchelkunov, I. S. AU - Shivappa, R. B. AU - Joiner, C. AU - Woolford, G. AU - Stone, D. M. AU - Dixon, P. F. AU - Raley, M. E. AU - Levine, J. F. T2 - DISEASES OF AQUATIC ORGANISMS AB - Genetic relationships between 35 spring viremia of carp virus (SVCV) genogroup Ia isolates were determined based on the nucleotide sequences of the phosphoprotein (P) gene and glycoprotein (G) genes. Phylogenetic analysis based on P gene sequences revealed 2 distinct subgroups within SVCV genogroup Ia, designated SVCV Iai and Iaii, and suggests at least 2 independent introductions of the virus into the USA in 2002. Combined P- and G-sequence data support the emergence of SVCV in Illinois, USA, and in Lake Ontario, Canada, from the initial outbreak in Wisconsin, USA, and demonstrate a close genetic link to viruses isolated during routine import checks on fish brought into the UK from Asia. The data also showed a genetic link between SVCV isolations made in Missouri and Washington, USA, in 2004 and the earlier isolation made in North Carolina, USA, in 2002. However, based on the close relationship to a 2004 UK isolate, the data suggest than the Washington isolate represents a third introduction into the US from a common source, rather than a reemergence from the 2002 isolate. There was strong phylogenetic support for an Asian origin for 9 of 16 UK viruses isolated either from imported fish, or shown to have been in direct contact with fish imported from Asia. In one case, there was 100% nucleotide identity in the G-gene with a virus isolated in China. DA - 2007/7/16/ PY - 2007/7/16/ DO - 10.3354/dao076193 VL - 76 IS - 3 SP - 193-204 SN - 1616-1580 KW - spring viremia of carp KW - SVCV KW - phosphoprotein gene KW - glycoprotein gene KW - phylogenetic analysis KW - molecular epidemiology ER - TY - JOUR TI - Is growth a reliable indicator of habitat quality and essential fish habitat for a juvenile estuarine fish? AU - Searcy, Steven P. AU - Eggleston, David B. AU - Hare, Jonathan A. T2 - CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES AB - A common assumption throughout the marine ecological and fisheries literature is that growth is a valid indicator of habitat quality and can be used as a criterion for designation of essential fish habitat (EFH). In this study, the validity of growth as an index of habitat quality was tested by examining how variability in otolith growth was related to abiotic and biotic environmental conditions and could be biased by previous growth history, density dependence, and selective mortality. The study was conducted with juvenile Atlantic croaker (Micropogonias undulatus) collected in two North Carolina, USA, estuaries during two seasons of two recruitment years. Water temperature, a component of habitat quality, explained nearly 40% of the variability in juvenile otolith growth. There was also evidence that estimates of growth could be biased by density dependence (slower growth at higher conspecific abundance) and by selective mortality (higher mortality of individuals with relatively slower larval and juvenile otolith growth). Studies using growth-based assessment of habitat quality that fail to identify factors underlying growth rate differences among habitats may reach incorrect decisions regarding quality of different habitats and assignment of EFH. DA - 2007/4// PY - 2007/4// DO - 10.1139/F07-038 VL - 64 IS - 4 SP - 681-691 SN - 1205-7533 ER - TY - JOUR TI - Density-dependent growth and mortality in an estuary-dependent fish: an experimental approach with juvenile spot Leiostomus xanthurus AU - Craig, J. Kevin AU - Rice, James A. AU - Crowder, Larry B. AU - Nadeau, David A. T2 - MARINE ECOLOGY PROGRESS SERIES AB - MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 343:251-262 (2007) - DOI: https://doi.org/10.3354/meps06864 Density-dependent growth and mortality in an estuary-dependent fish: an experimental approach with juvenile spot Leiostomus xanthurus J. Kevin Craig1,5,*, James A. Rice2, Larry B. Crowder3, David A. Nadeau4 1Department of Zoology, Center for Marine Sciences and Technology, North Carolina State University, 303 College Circle, Morehead City, North Carolina 28557, USA 2Department of Zoology, North Carolina State University, Raleigh, North Carolina 27695-7617, USA 3Nicholas School of the Environment and Earth Sciences, Duke Center for Marine Conservation, 135 Duke Marine Lab Rd., Beaufort, North Carolina 28516-9721, USA 4MarineLab, Marine Resources Development Foundation, 51 Shoreland Drive, Key Largo, Florida 33037, USA 5Present address: Florida State University Coastal and Marine Laboratrory, 3618 Highway 98, St. Teresa, Florida 32358-2702, USA *Email: kevin_craig@ncsu.edu ABSTRACT: The abundance of demersal marine fishes is a function of both pre-settlement processes that influence recruitment to benthic juvenile habitats, as well as post-settlement density-dependent processes that act during the juvenile stage. Few studies have investigated density-dependence for fishes that spawn offshore and recruit to inshore estuaries for the juvenile stage prior to returning to offshore waters as adults (i.e. estuary-dependent). We conducted 2 replicated experiments at different spatial scales to test for density-dependent growth and mortality in juvenile spot Leiostomus xanthurus, a common estuary-dependent species. In the small-scale experiment, we stocked spot in 1 m2 cages in a marsh creek at densities of 2, 5, and 10 fish m–2 and determined their growth and mortality after 51 d. In the large-scale experiment, we stocked spot in 79 m2 pond sections at 2, 5, and 10 fish m–2 and determined their growth and mortality after 52 d. We sampled benthic infauna at the end of the pond experiment to determine if prey availability mediated the effects of density on spot growth and mortality. Average spot growth rates decreased 83 to 97% and mortality increased 2- to 4-fold as density increased from 2 to 10 fish m–2. The density of benthic infauna at the end of the pond experiment was inversely related to spot density, consistent with competition for food as the underlying mechanism. Estimates of spot density compiled from the literature indicate that the density-dependent effects we observed occurred within the range of reported field densities. Our results provide strong experimental support for the hypothesis that density-dependent processes during the demersal juvenile stage in estuaries can modify patterns in the abundance of spot, and perhaps other estuary-dependent species, that are established prior to settlement. KEY WORDS: Density-dependent growth · Density-dependent mortality · Spot · Leiostomus xanthurus · Estuarine nursery · Food limitation Full text in pdf format PreviousNextCite this article as: Craig JK, Rice JA, Crowder LB, Nadeau DA (2007) Density-dependent growth and mortality in an estuary-dependent fish: an experimental approach with juvenile spot Leiostomus xanthurus. Mar Ecol Prog Ser 343:251-262. https://doi.org/10.3354/meps06864 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 343. Online publication date: August 07, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research. DA - 2007/// PY - 2007/// DO - 10.3354/meps06864 VL - 343 SP - 251-262 SN - 1616-1599 KW - density-dependent growth KW - density-dependent mortality KW - spot KW - Leiostomus xanthurus KW - estuarine nursery KW - food limitation ER - TY - JOUR TI - Atlantic Southern Ocean productivity: Fertilization from above or below? AU - Meskhidze, Nicholas AU - Nenes, Athanasios AU - Chameides, William L. AU - Luo, Chao AU - Mahowald, Natalie T2 - GLOBAL BIOGEOCHEMICAL CYCLES AB - Primary productivity and the associated uptake of atmospheric carbon dioxide in the Southern Ocean (SO) is thought to be generally limited by bioavailable iron (Fe). Two sources of Fe for the surface waters of the SO have been proposed: (1) oceanic input of nutrient‐rich (i.e., Fe) waters from upwelling and lateral flows from continental margins; and (2) atmospheric input from the deposition of mineral dust emanating from the arid regions of South America and Australia. In this work, analysis of weekly remotely sensed sea surface temperature (SST), ocean chlorophyll a content [Chl a ] and model‐derived atmospheric dust‐Fe fluxes are used to identify the predominant source of Fe during phytoplankton blooms in the surface waters of the south Atlantic Ocean between 40°S and 60°S. The results of our study suggest that oceanic source through upwelling of nutrient‐rich waters due to mesoscale frontal dynamics is the major source of bioavailable Fe controlling biological activity in this region. This result is consistent with the idea that acidification of aeolian dust prior to its deposition to the ocean may be required to solubilize the large fraction of mineral‐iron and make it bioavailable. DA - 2007/4/24/ PY - 2007/4/24/ DO - 10.1029/2006gb002711 VL - 21 IS - 2 SP - SN - 1944-9224 ER - TY - JOUR TI - The impact of coastal boundaries and small hills on the precipitation distribution across southern Connecticut and Long Island, New York AU - Colle, Brian A. AU - Yuter, Sandra E. T2 - MONTHLY WEATHER REVIEW AB - Abstract The modification of precipitation by the coastal land areas of Long Island (LI), New York, and southern Connecticut (CT) is examined for an extratropical cyclone over the northeast United States on 1 December 2004, which produced strong southerly flow (15–30 m s−1) below 900 mb and heavy precipitation over LI. The differential surface roughness at the coast and the hills of LI (30–80 m) and southern CT (100–250 m) enhanced the surface precipitation by 30%–50% over these regions compared with the nearby water region of LI Sound. The three-dimensional precipitation structures are shown using composite Weather Surveillance Radar-1988 Doppler radar data interpolated to a Cartesian grid, which is compared with a 4-km simulation using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). As the low-level stratification and flow increased at low levels, the MM5 produced a terrain-forced gravity wave over LI and CT upward through 6 km MSL. Precipitation enhancement (2–3 dBZ) occurred from the surface upward to around the freezing level (3 km MSL) across central LI and southern CT, while there was a localized precipitation minimum over LI Sound. A factor separation on a few sensitivity MM5 runs was performed to isolate the impact of small hills and differential friction across the LI coastline. Both the hills and frictional effects have similar contributions to the total precipitation enhancement and the vertical circulations below 3 km. The hills of LI enhanced the gravity wave circulations slightly more than the differential friction above 3 km, while there was little flow and precipitation interaction between the hills and differential friction. A sensitivity simulation without an ice/snow cloud above 3 km MSL revealed that the seeder-feeder process enhanced surface precipitation by about a factor of 4. DA - 2007/3// PY - 2007/3// DO - 10.1175/MWR3320.1 VL - 135 IS - 3 SP - 933-954 SN - 0027-0644 ER - TY - JOUR TI - The effects of a mountain on the propagation of a preexisting convective system for blocked and unblocked flow regimes AU - Reeves, Heather Dawn AU - Lin, Yuh-Lang T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract Observations and previous research of squall lines impinging on mountain ranges have revealed that the squall lines sometimes stall upstream of the mountains for several hours leading to copious accumulations of precipitation. It has been hypothesized that squall-line stagnation may be more prone to occur in flows where the Froude number (F = U/Nh, where U is the basic-state wind, N is the Brunt–Väisälä frequency, and h is the mountain height) is low. This hypothesis is tested herein through a series of idealized, two-dimensional experiments where a convective system was triggered upstream of a mesoscale mountain in conditionally unstable flow. For simulations with relatively low Froude numbers, stagnation of the preexisting convective system was not observed. In the simulations with high values of F, squall lines were noted to stagnate between 100 and 200 km upstream of the mountain. This result indicates that squall-line stagnation may be more favored for moderate to large values of F for conditionally unstable flow. The mechanisms leading to the formation of the stationary convective system upstream of the mountain in the unblocked flows were explored and it was found that evaporative cooling played a pivotal role in the stagnation of the squall line. DA - 2007/7// PY - 2007/7// DO - 10.1175/JAS3959.1 VL - 64 IS - 7 SP - 2401-2421 SN - 1520-0469 ER - TY - JOUR TI - Seminal and endocrine characteristics of male Pallas' Cats (Otocolobus manul) maintained under artificial lighting with simulated natural photoperiods AU - Newell-Fugate, Annie AU - Kennedy-Stoskopf, Suzanne AU - Brown, Janine L. AU - Levine, Jay F. AU - Swanson, William F. T2 - Zoo Biology AB - Abstract Pallas' cats ( Otocolobus manul ) have a pronounced reproductive seasonality controlled by photoperiod. Previous studies of reproduction in captive Pallas' cats exposed to natural light showed a breeding season of December–April. This study evaluated the impact of artificial lighting timed to simulate natural photoperiods on male reproductive seasonality of four Pallas' cats housed indoors. Semen evaluation, blood collection, and body weight measurements were conducted every 1–2 months from November 2000–June 2001. Fecal samples were collected from each male twice weekly to assess testosterone and corticoid concentrations. Mean values for reproductive traits (sperm attributes, testicular volume) were highest from February–April, the defined breeding season. Fecal testosterone concentrations were highest from mid‐January to mid‐March. Male Pallas' cats managed indoors under simulated photoperiods experienced a delayed onset of the breeding season by 1–2 months and a decreased length of the breeding season. Over the course of the study, fecal corticoid concentrations did not seem to differ among seasons. Although mating attempts during this study were unsuccessful, subsequent pairings of male and female Pallas' cats in the same research colony during the 2002 and 2003 breeding seasons produced viable offspring. These results suggest that male Pallas' cats, housed indoors under simulated photoperiods, exhibit distinct reproductive cyclic patterns, characterized by a delayed and truncated breeding season. Adrenocortical activity varied among individuals, but did not adversely affect reproductive parameters. Housing Pallas' cats indoors under simulated photoperiods may represent a viable strategy for maintaining breeding success while limiting disease exposure. Zoo Biol 0:1–13, 2007. © 2007 Wiley‐Liss, Inc. DA - 2007/5// PY - 2007/5// DO - 10.1002/zoo.20127 VL - 26 IS - 3 SP - 187-199 J2 - Zoo Biol. LA - en OP - SN - 0733-3188 1098-2361 UR - http://dx.doi.org/10.1002/zoo.20127 DB - Crossref KW - felids KW - testosterone KW - cortisol KW - leptin KW - spermatozoa KW - reproductive seasonality ER - TY - JOUR TI - Rapid dike emplacement leads to eruptions and hydrothermal plume release during seafloor spreading events AU - Dziak, R. P. AU - Bohnenstiehl, D. R. AU - Cowen, J. P. AU - Baker, E. T. AU - Rubin, K. H. AU - Haxel, J. H. AU - Fowler, M. J. T2 - GEOLOGY AB - Research Article| July 01, 2007 Rapid dike emplacement leads to eruptions and hydrothermal plume release during seafloor spreading events R.P. Dziak; R.P. Dziak 1Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA Search for other works by this author on: GSW Google Scholar D.R Bohnenstiehl; D.R Bohnenstiehl 2Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Rayleigh, North Carolina 27695, USA Search for other works by this author on: GSW Google Scholar J.P. Cowen; J.P. Cowen 3Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96817, USA Search for other works by this author on: GSW Google Scholar E.T. Baker; E.T. Baker 4Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Seattle, Washington 98115, USA Search for other works by this author on: GSW Google Scholar K.H. Rubin; K.H. Rubin 5Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96817, USA Search for other works by this author on: GSW Google Scholar J.H. Haxel; J.H. Haxel 6Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA Search for other works by this author on: GSW Google Scholar M.J. Fowler M.J. Fowler 6Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA Search for other works by this author on: GSW Google Scholar Author and Article Information R.P. Dziak 1Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA D.R Bohnenstiehl 2Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Rayleigh, North Carolina 27695, USA J.P. Cowen 3Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96817, USA E.T. Baker 4Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Seattle, Washington 98115, USA K.H. Rubin 5Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96817, USA J.H. Haxel 6Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA M.J. Fowler 6Cooperative Institute for Marine Resource Studies, Oregon State University, and Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Hatfield Marine Science Center, Newport, Oregon 97365, USA Publisher: Geological Society of America Received: 30 Oct 2006 Revision Received: 01 Feb 2007 Accepted: 07 Feb 2007 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2007) 35 (7): 579–582. https://doi.org/10.1130/G23476A.1 Article history Received: 30 Oct 2006 Revision Received: 01 Feb 2007 Accepted: 07 Feb 2007 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation R.P. Dziak, D.R Bohnenstiehl, J.P. Cowen, E.T. Baker, K.H. Rubin, J.H. Haxel, M.J. Fowler; Rapid dike emplacement leads to eruptions and hydrothermal plume release during seafloor spreading events. Geology 2007;; 35 (7): 579–582. doi: https://doi.org/10.1130/G23476A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The creation of ocean crust by rapid injection of magma at mid-ocean ridges can lead to eruptions of lava onto the seafloor and release of “event plumes,” which are huge volumes of anomalously warm water enriched in reduced chemicals that rise up to 1 km above the seafloor. Here, we use seismic data to show that seafloor eruptions and the release of hydrothermal event plumes correspond to diking episodes with high injection velocities and rapid onset of magma emplacement within the rift zone. These attributes result from high excess magma pressure at the dike source, likely due to a new influx of melt from the mantle. These dynamic magmatic conditions can be detected remotely and may predict the likelihood of event plume release during future seafloor spreading events. You do not have access to this content, please speak to your institutional administrator if you feel you should have access. DA - 2007/7// PY - 2007/7// DO - 10.1130/g23476a.1 VL - 35 IS - 7 SP - 579-582 SN - 0091-7613 KW - dike injection KW - earthquakes KW - hydroacoustics KW - ridge KW - Juan de Fuca ER - TY - JOUR TI - Polychlorinated Biphenyl Exposure Causes Gonadal Atrophy and Oxidative Stress in Corbicula fluminea Clams AU - Lehmann, Daniel W. AU - Levine, Jay F. AU - Law, J. Mchugh T2 - Toxicologic Pathology AB - Polychlorinated biphenyls (PCBs) are widespread environmental contaminants that have been linked to oxidative and other toxic effects in both humans and wildlife. Due to recent environmental health concerns at a PCB contaminated Superfund site near Raleigh, NC, we used a common clam species ( Corbicula fluminea) as surrogates to isolate the effects of PCBs on threatened bivalves native to the region. Under controlled laboratory conditions, clams were exposed to 0, 1, 10, or 100 ppb Aroclor 1260 in the ambient water for 21 days. Measured biomarkers spanned a range of effective levels of biological organization including low molecular weight antioxidants, lipid-soluble antioxidants, and whole tissue radical absorption capacity. These data were augmented by use of histological evaluation of whole samples. Aroclor 1260 significantly increased reduced glutathione (GSH) and total protein concentrations at all treatments levels. Significant decreases were measured in all treatments in γ-tocopherol and total oxidant scavenging capacity (TOSC) and α-tocopherol values in the 100 ppb exposure. Histologically, Aroclor 1260 caused significant gonadal atrophy, effacement of gonad architecture with accumulations of Brown cells, and inflammation and necrosis in digestive glands and foot processes. Our results indicate that oxidative mechanisms play a significant role in the decreased health of these clams due to exposure to Aroclor 1260. The changes in the gonads of exposed clams suggest that a serious threat to bivalve reproduction exists due to PCB exposure. DA - 2007/4// PY - 2007/4// DO - 10.1080/01926230701230288 VL - 35 IS - 3 SP - 356-365 J2 - Toxicol Pathol LA - en OP - SN - 0192-6233 1533-1601 UR - http://dx.doi.org/10.1080/01926230701230288 DB - Crossref KW - PCB KW - polychlorinated biphenyl KW - oxidative stress KW - gonadal atrophy KW - Corbicula clams KW - Aroclor KW - antioxidant ER - TY - JOUR TI - Phytoplankton and bacterial assemblages in ballast water of US military ships as a function of port of origin, voyage time, and ocean exchange practices AU - Burkholder, J. M. AU - G. M., Melia AU - G., Cohen AU - A., Bowers AU - H. A., Oldach AU - D. W., Parrow AU - M. W., Sullivan AU - M. J., Zimba AU - P. V., Allen AU - E. H., Kinder AU - C. A., AU - Mallin, M. A. T2 - Harmful Algae DA - 2007/// PY - 2007/// VL - 6 IS - 4 SP - 486-518 ER - TY - PCOMM TI - Isoprene, cloud droplets, and phytoplankton - Response AU - Meskhidze, N. AU - Nenes, A. DA - 2007/// PY - 2007/// SP - 42-43 ER - TY - JOUR TI - Effect of bathymetric curvature on gulf stream instability in the vicinity of the Charleston Bump AU - Xie, Lian AU - Liu, Xiaoming AU - Pietrafesa, Leonard J. T2 - JOURNAL OF PHYSICAL OCEANOGRAPHY AB - Abstract The effect of the isobathic curvature on the development and evolution of Gulf Stream frontal waves (meanders and eddies) in the vicinity of the Charleston Bump (a topographic rise on the upper slope off Charleston, South Carolina; referred to as CB hereinafter) is studied using the Hybrid-Coordinate Ocean Model (HYCOM). Baroclinic and barotropic energy transfers from the Gulf Stream to its meanders and eddies that appear as cold and warm anomalies are computed for four different cases. In case I, the curvature of the isobaths is artificially reduced and the CB is removed from the bathymetry. In this simulation, the simulated Gulf Stream meanders were barely noticeable in the study region. Energy transfer from the Gulf Stream to meanders and eddies was negligible. In case II, the curvature of the isobaths was the same as in case I, but a bump of the scale of the CB was added to the bathymetry. In this simulation, Gulf Stream meanders were amplified while passing over the CB. In case III, the CB was removed from the bathymetry as in case I, but the curvature of the isobaths was similar to the actual bathymetry, which was larger than that of cases I and II. In this simulation, large meanders were simulated, but the development of these meanders was not confined to the region of the CB. The total baroclinic and barotropic energy transfer rate in this case was an order of magnitude greater than in case II, suggesting that isobathic curvature was able to generate Gulf Stream meanders and eddies even without the presence of the CB. In case IV, actual bathymetry data, which contain both the CB and the isobathic curvature, were used. In this case, large-amplitude Gulf Stream meanders were simulated and there was also a tendency for the amplification of the meanders to be anchored downstream of the CB, consistent with observations. The results from this study suggest that the formation of the “Charleston Trough,” a Gulf Stream meander that appears as a low pressure or depressed water surface region downstream of the bump, is the result of the combined effect of the CB and the isobathic curvature in the region. The isobathic curvature plays a major role in enhancing the baroclinic and barotropic energy transfer rates, whereas the bump provided a localized mechanism to maximize the energy transfer rate downstream of the CB. DA - 2007/3// PY - 2007/3// DO - 10.1175/JPO2995.1 VL - 37 IS - 3 SP - 452-475 SN - 0022-3670 ER - TY - JOUR TI - Design of a light-oil piezomanometer for measurement of hydraulic head differences and collection of groundwater samples AU - Kennedy, Casey D. AU - Genereux, David P. AU - Corbett, D. Reide AU - Mitasova, Helena T2 - WATER RESOURCES RESEARCH AB - This paper describes a device (“piezomanometer”) that combines three components (an oil‐water manometer, a pushable screened PVC probe, and a system for groundwater sample collection) into a single inexpensive ($130), easily built, reliable tool for rapid collection of shallow groundwater from a streambed or lake bed and accurate measurement of even very small head differences between this groundwater and overlying surface water. The piezomanometer has been tested with excellent results both in the lab and in a stream shallow enough for wading; in principle, it could be adapted for use in deeper water where work is done from a dock, boat, or other platform. The problem of gas bubbles collecting in the groundwater line (a common drawback of field manometers) was nearly eliminated by use of a three‐way valve at a local elevation maximum in the groundwater line (gas bubbles in the groundwater line can be purged through this valve). Field application is illustrated here with data from a 2‐day study using four piezomanometers in a North Carolina stream. DA - 2007/9/7/ PY - 2007/9/7/ DO - 10.1029/2007wr005904 VL - 43 IS - 9 SP - SN - 1944-7973 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35848960791&partnerID=MN8TOARS ER - TY - JOUR TI - A comparative analysis of pre-Silurlan crustal building blocks of the northern and the southern Appalachian orogen AU - Hibbard, James P. AU - Van Staal, Cees R. AU - Rankin, Douglas W. T2 - AMERICAN JOURNAL OF SCIENCE AB - The New York promontory serves as the divide between the northern and southern segments of the Appalachian orogen. Antiquated subdivisions, distinct for each segment, implied that they had lithotectonic histories that were independent of each other. Using new lithotectonic subdivisions we compare first order features of the pre-Silurian orogenic 'building blocks' in order to test the validity of the implication of independent lithotectonic histories for the two segments. Three lithotectonic divisions, termed here the Laurentian, Iapetan, and the peri-Gondwanan realms, characterize the entire orogen. The Laurentian realm, composed of native North American rocks, is remarkably uniform for the length of the orogen. It records the multistage Neoproterozoic-early Paleozoic rift-drift history of the Appalachian passive margin, formation of a Taconic Seaway, and the ultimate demise of both in the Middle Ordovician. The Iapetan realm encompasses mainly oceanic and magmatic arc tracts that once lay within the Iapetus Ocean, between Laurentia and Gondwana. In the northern segment, the realm is divisible on the basis of stratigraphy and faunal provinciality into peri-Laurentian and peri-Gondwanan tracts that were amalgamated in the Late Ordovician. South of New York, stratigraphic and faunal controls decrease markedly; rock associations are not inconsistent with those of the northern Appalachians, although second-order differences exist. Exposed exotic crustal blocks of the peri-Gondwanan realm include Ganderia, Avalonia, and Meguma in the north, and Carolinia in the south. Carolinia most closely resembles Ganderia, both in early evolution and Late Ordovician-Silurian docking to Laurentia. Our comparison indicates that, to a first order, the pre-Silurian Appalachian orogen developed uniformly, starting with complex rifting and a subsequent drift phase to form the Appalachian margin, followed by the consolidation of Iapetan components and ending with accretion of the peri-Gonwanan Ganderia and Carolinia. This deduction implies that any first-order differences between northern and southern segments post-date Late Ordovician consolidation of a large portion of the orogen. DA - 2007/1// PY - 2007/1// DO - 10.2475/01.2007.02 VL - 307 IS - 1 SP - 23-45 SN - 1945-452X ER - TY - JOUR TI - A basal Dromaeosaurid and size evolution preceding avian flight AU - Turner, Alan H. AU - Pol, Diego AU - Clarke, Julia A. AU - Erickson, Gregory M. AU - Norell, Mark A. T2 - SCIENCE AB - Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional. DA - 2007/9/7/ PY - 2007/9/7/ DO - 10.1126/science.1144066 VL - 317 IS - 5843 SP - 1378-1381 SN - 1095-9203 ER - TY - JOUR TI - Variability of East African rainfall based on multiyear RegCM3 simulations AU - Anyah, Richard O. AU - Semazzi, Fredrick H. M. T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY AB - Abstract The International Center for Theoretical Physics (ICTP) regional climate model version 3 (ICTP‐RegCM3) multiyear simulations of East Africa rainfall during the October–December, short rains season are evaluated. Two parallel runs; based on NCEP reanalysis and NASA FvGCM lateral boundary conditions are performed. The simulated monthly and seasonal rainfall climatology as well as the interannual variability are found to be fairly consistent with the observations. The model climatology over specific homogeneous climate subregions, except central Kenya (CKE) highlands, also reasonably agrees with the observed. The latitude‐time evolution (intraseasonal variability) of the simulated seasonal rainfall exhibits two distinct modes of behavior. The first is a quasistationary mode associated with high rainfall throughout the season within the equatorial belt between 1°S and 2°N. The second mode is associated with the intertropical convergence zone (ITCZ)‐driven southward migration of regions of rainfall maxima as the season progresses, which is also consistent with the observed. Furthermore, observed rainfall variability over distinct homogeneous climate subregions is also fairly reproduced by the model, except over central Kenya highlands and northeastern parts of Kenya. The spatial correlation between the simulated seasonal rainfall and some of the global teleconnections (DMI and Nino3.4 indices) shows that the regional model conserves some of the observed regional ‘hot spots’ where rainfall‐ENSO/DMI associations are strong. At the same time, unlike observations, the model reveals that along the East Africa Rift Valley and over western parts of the Lake Victoria Basin, the association is weak, perhaps an indication that nonlinear interactions between local forcing (captured by the model) and large‐scale systems either suppress or obscur the dominant influence of the teleconnections on rainfall over certain parts. Copyright © 2006 Royal Meteorological Society. DA - 2007/3/15/ PY - 2007/3/15/ DO - 10.1002/joc.1401 VL - 27 IS - 3 SP - 357-371 SN - 1097-0088 ER - TY - JOUR TI - Temporal and spatial variability in stable isotope compositions of a freshwater mussel: implications for biomonitoring and ecological studies AU - Gustafson, Lori AU - Showers, William AU - Kwak, Thomas AU - Levine, Jay AU - Stoskopf, Michael T2 - OECOLOGIA DA - 2007/5// PY - 2007/5// DO - 10.1007/s00442-006-0633-7 VL - 152 IS - 1 SP - 140-150 SN - 1432-1939 KW - Elliptio complanata KW - delta N-15 KW - delta C-13 KW - nutrient loading KW - tissue turnover KW - isotopic baseline ER - TY - JOUR TI - Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon AU - Simpson, Matthew AU - Warrior, Hari AU - Raman, Sethu AU - Aswathanarayana, P. A. AU - Mohanty, U. C. AU - Suresh, R. T2 - NATURAL HAZARDS AB - Sea-breeze-initiated convection and precipitation have been investigated along the east coast of India during the Indian southwest monsoon season. Sea-breeze circulation was observed on approximately 70–80% of days during the summer months (June–August) along the Chennai coast. Average sea-breeze wind speeds are greater at rural locations than in the urban region of Chennai. Sea-breeze circulation was shown to be the dominant mechanism initiating rainfall during the Indian southwest monsoon season. Approximately 80% of the total rainfall observed during the southwest monsoon over Chennai is directly related to convection initiated by sea-breeze circulation. DA - 2007/8// PY - 2007/8// DO - 10.1007/s11069-006-9081-2 VL - 42 IS - 2 SP - 401-413 SN - 1573-0840 KW - sea breeze KW - monsoon KW - mesoscale circulation ER - TY - JOUR TI - Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and Cenozoic climate change AU - Clarke, Julia A. AU - Ksepka, Daniel T. AU - Stucchie, Marcelo AU - Urbina, Mario AU - Giannini, Norberto AU - Bertelli, Sara AU - Narvez, Yanina AU - Boyd, Clint A. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - New penguin fossils from the Eocene of Peru force a reevaluation of previous hypotheses regarding the causal role of climate change in penguin evolution. Repeatedly it has been proposed that penguins originated in high southern latitudes and arrived at equatorial regions relatively recently (e.g., 4-8 million years ago), well after the onset of latest Eocene/Oligocene global cooling and increases in polar ice volume. By contrast, new discoveries from the middle and late Eocene of Peru reveal that penguins invaded low latitudes >30 million years earlier than prior data suggested, during one of the warmest intervals of the Cenozoic. A diverse fauna includes two new species, here reported from two of the best exemplars of Paleogene penguins yet recovered. The most comprehensive phylogenetic analysis of Sphenisciformes to date, combining morphological and molecular data, places the new species outside the extant penguin radiation (crown clade: Spheniscidae) and supports two separate dispersals to equatorial (paleolatitude approximately 14 degrees S) regions during greenhouse earth conditions. One new species, Perudyptes devriesi, is among the deepest divergences within Sphenisciformes. The second, Icadyptes salasi, is the most complete giant (>1.5 m standing height) penguin yet described. Both species provide critical information on early penguin cranial osteology, trends in penguin body size, and the evolution of the penguin flipper. DA - 2007/7/10/ PY - 2007/7/10/ DO - 10.1073/pnas.0611099104 VL - 104 IS - 28 SP - 11545-11550 SN - 0027-8424 KW - aves KW - evolution KW - Peru KW - fossil KW - Bergmann's rule ER - TY - JOUR TI - Modification of the loop current warm core eddy by Hurricane Gilbert (1988) AU - Hong, Xiaodong AU - Chang, Simon W. AU - Raman, Sethu T2 - NATURAL HAZARDS DA - 2007/6// PY - 2007/6// DO - 10.1007/s11069-006-9057-2 VL - 41 IS - 3 SP - 501-514 SN - 0921-030X KW - Hurricane Gilbert KW - warm core eddy KW - near-inertial oscillation KW - ocean response ER - TY - JOUR TI - High-resolution numerical simulations of hurricane Isabel (2003) over North Carolina AU - Childs, Peter AU - Raman, Sethu AU - Boyles, Ryan T2 - NATURAL HAZARDS DA - 2007/6// PY - 2007/6// DO - 10.1007/s11069-006-9050-9 VL - 41 IS - 3 SP - 401-411 SN - 0921-030X KW - sea surface temperature KW - flux KW - climatological KW - resolution KW - data assimilation ER - TY - JOUR TI - Effects of temperature and nitrate on phosphomonoesterase activities between carbon source and sink tissues in Zostera marina L. AU - Touchette, Brant W. AU - Burkholder, JoAnn M. T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Inorganic phosphorus (Pi) is important in the regulation of many carbon and nitrogen metabolic processes of plants. In this study, we examined alterations of phosphomonoesterase activity (PA; both alkaline and acid) in a submersed marine angiosperm, Zostera marina, grown in Pi non-limiting conditions under elevated temperature and/or nitrate enrichment. Control plants (ambient water-column NO3− < 2.5 μM, with weekly mean water temperatures between 26.5–27.0 °C based on a 20-yr data set in a local embayment) were compared to treated plants that were exposed to increased water-column nitrate (8 μM NO3− above ambient, pulsed daily at 0900 h), and/or increased temperature (ca. 3 °C above weekly means) over eight weeks in late summer–fall. Under both nitrate regimes, increased temperature resulted in periodic increased leaf and root-rhizome tissue carbon content, and increased acid and alkaline PA activities (AcPAs and AlPAs, respectively). There was a positive correlation between AlPA and AcPA activities and sucrose synthase activities in belowground structures, and a negative correlation between AlPA activities and sucrose concentrations. There were also periodic changes in PA partitioning between carbon source and sink tissues. In high-temperature and high-nitrate treatments, AcPAs significantly increased in leaves relative to activities in root-rhizome tissues (up to 12-fold higher in aboveground than belowground tissues in as little as 3 weeks after initiation of treatments). These responses were not observed in control plants, which maintained comparable AcPA activities in above- and belowground tissues. In addition, AlPA activity was significantly higher in leaf than in root-rhizome tissues of plants in high-temperature (weeks 3 and 6) and high temperature combined with high nitrate treatments (week 8), relative to AlPA activities in control plants. The observed changes in PAs were not related to Pi growth limitation, and may allow Z. marina to alter its carbon metabolism during periods of increased carbon demand/mobilization. This response would make it possible for Z. marina to meet short-term P requirements to maximize carbon production/allocation. Such a mechanism could help to explain the variability in PA activities that has been observed for many plant species during periods when environmental Pi exceeds requirements for optimal growth. DA - 2007/4/16/ PY - 2007/4/16/ DO - 10.1016/j.jembe.2006.11.005 VL - 342 IS - 2 SP - 313-324 SN - 1879-1697 KW - carbon metabolism KW - nitrate enrichment KW - phosphatase KW - sucrose synthase KW - seagrass KW - temperature KW - Zostera marina ER - TY - JOUR TI - West North Pacific typhoon track patterns and their potential connection to Tibetan Plateau snow cover AU - Xie, Lian AU - Yan, Tingzhuang T2 - NATURAL HAZARDS DA - 2007/8// PY - 2007/8// DO - 10.1007/s11069-006-9087-9 VL - 42 IS - 2 SP - 317-333 SN - 1573-0840 KW - climate variability KW - TP snow cover KW - typhoon KW - Western North Pacific/East Asian summer monsoon ER - TY - JOUR TI - U-Pb detrital zircon geochronological constraints on the Early Silurian collision of Ganderia and Laurentia along the Dog Bay Line: The terminal Iapetan suture in the Newfoundland Appalachians AU - Pollock, J. C. AU - Wilton, D. H. C. AU - Van Staal, C. R. AU - Morrissey, K. D. T2 - American Journal of Science DA - 2007/// PY - 2007/// VL - 307 IS - 2 SP - 399-433 ER - TY - JOUR TI - Sensitivity of wind waves to hurricane wind characteristics AU - Liu, Huiqing AU - Xie, Lian AU - Pietrafesa, Leonard J. AU - Bao, Shaowu T2 - OCEAN MODELLING AB - In this study, the influence of the spatial and temporal variability of hurricane winds, storm translation speed, intensity, and ambient wind field on surface wind waves are investigated by using a third-generation wave model (Simulating WAves Nearshore, or SWAN). The results show that the asymmetric structure of wind-induced wave field is sensitive not only to the asymmetric structure of the hurricane wind field, but also to the variations in the storm translation speed and intensity. The significant wave height (SWH) in the front-right quadrant of the storm rises as storm translation speed increases until it reaches a critical value, then the SWH drops. The opposite occurs in the rear-left quadrant. The total contribution of the hurricane translation speed to the asymmetric structure of the wave field also depends on the intensity of the hurricane. As the intensity of the hurricane increases, the relative significance of the influence of the translation speed on the asymmetric structure of the wave field decreases. Most parametric hurricane wind models can only model symmetric hurricanes and do not include background winds. However, actual hurricanes in nature are not only asymmetric but also imbedded in background winds. Thus, to more properly model hurricane-induced wave field, it is important to consider storm asymmetry, translation speed, intensity, as well as background winds. DA - 2007/// PY - 2007/// DO - 10.1016/j.ocemod.2007.03.004 VL - 18 IS - 1 SP - 37-52 SN - 1463-5003 KW - wave KW - hurricane KW - numerical modeling KW - ocean response KW - wind forcing ER - TY - JOUR TI - Sensitivity of mesoscale surface dynamics to surface soil and vegetation contrasts over the carolina sandhills AU - Boyles, Ryan AU - Raman, Sethu AU - Sims, Aaron T2 - PURE AND APPLIED GEOPHYSICS DA - 2007/9// PY - 2007/9// DO - 10.1007/s00024-007-0227-2 VL - 164 IS - 8-9 SP - 1547-1576 SN - 0033-4553 KW - land surface variation KW - North Carolina KW - soils ER - TY - JOUR TI - Preface AU - Sharan, Maithili AU - Raman, Sethu T2 - PURE AND APPLIED GEOPHYSICS DA - 2007/9// PY - 2007/9// DO - 10.1007/s00024-007-0226-3 VL - 164 IS - 8-9 SP - 1423-1425 SN - 0033-4553 ER - TY - JOUR TI - Models as educational tools AU - Orf, Leigh AU - Lackmann, Gary AU - Herbster, Chris AU - Krueger, Anton AU - Cutrim, Elen AU - Whitaker, Tom AU - Steenburgh, Jim AU - Voss, Michael T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY DA - 2007/7// PY - 2007/7// DO - 10.1175/bams-88-7-1101 VL - 88 IS - 7 SP - 1101-1104 SN - 0003-0007 ER - TY - JOUR TI - Mitochondrial Multiplex Real-Time PCR as a Source Tracking Method in Fecal-Contaminated Effluents AU - Caldwell, Jane M. AU - Raley, Morgan E. AU - Levine, Jay F. T2 - Environmental Science & Technology AB - Multiplex real-time PCR amplifying fecal mitochondrial DNA (mtDNA) combined with rapid, crude DNA preparations are promising additions to surface water source tracking methods. Amplification of eukaryotic mitochondrial DNA identifies the fecal source directly and can be used in conjunction with other intestinal microbial methods to characterize effluents. Species-specific primers and dual-labeled probes for human, swine, and bovine NADH dehydrogenase subunit 5 (ND5) genes were created for multiplex real-time PCR in feces and effluent slurries. The linear range of the multiplex assay was 10(2)-10(7) mtDNA copies for human, bovine, and swine effluent in combination (equal volumes). PCR amplification efficiencies for bovine, human, and swine mtDNA when assayed in combination were 93, 107, and 92% respectively. Linear regression correlation coefficients (r2) were 0.99 for all standard curves except for human mtDNA in combination (r2 = 0.95). Multiplex amplification of bovine, human, and swine mtDNA (ND5) exhibited no cross-reactions between the effluents from three species of interest. Also, no cross-reactions were observed with effluents of other vertebrates: sheep, goat, horse, dog, cat, Canada goose, broiler, layer, turkey, and tilapia. Performed as a blind test, the PCR operator was able to correctly identify all but two effluent challenge samples (10/12 or 83% correct) with no false positives (22/22 or 100% correct). The multiplex assay had a tendency to detect the species of highest mtDNA concentration only. Better detection of all three species in a combination of human, bovine, and swine effluents was accomplished by running each real-time PCR primer/ probe set singly. Real-time PCR detection limit was calculated as 2.0 x 10(6) mitochondrial copies or 0.2 g of human feces per 100 mL effluent. Some carry-over mtDNA PCR signal from consumed beef, but not pork, was found in feces of human volunteers. DA - 2007/5// PY - 2007/5// DO - 10.1021/es062912s VL - 41 IS - 9 SP - 3277-3283 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/es062912s DB - Crossref ER - TY - JOUR TI - Editorial AU - Mohanty, U. C. AU - Raman, Sethu AU - Rao, D. V. Bhaskar T2 - NATURAL HAZARDS DA - 2007/8// PY - 2007/8// DO - 10.1007/s11069-006-9078-x VL - 42 IS - 2 SP - 253-255 SN - 1573-0840 ER - TY - JOUR TI - Correcting the errors in the initial conditions and wind stress in storm surge simulation using an adjoint optimal technique AU - Peng, S. Q. AU - Xie, L. AU - Pietrafesa, L. J. T2 - Ocean Modelling (Oxford, England) AB - An adjoint data assimilation methodology is applied to the Princeton Ocean Model and is evaluated by obtaining “optimal” initial conditions, sea surface forcing conditions, or both for coastal storm surge modelling. By prescribing different error sources and setting the corresponding control variables, we performed several sets of identical twin experiments by assimilating model-generated water levels. The experiment results show that, when the forecasting errors are caused by the initial (or surface boundary) conditions, adjusting initial (or surface boundary) conditions accordingly can significantly improve the storm surge simulation. However, when the forecasting errors are caused by surface boundary (or initial) conditions, data assimilation targeting improving the initial (or surface boundary) conditions is ineffective. When the forecasting errors are caused by both the initial and surface boundary conditions, adjusting both the initial and surface boundary conditions leads to the best results. In practice, we do not know whether the errors are caused by initial conditions or surface boundary conditions, therefore it is better to adjust both initial and surface boundary conditions in adjoint data assimilation. DA - 2007/// PY - 2007/// DO - 10.1016/j.ocemod.2007.04.002 VL - 18 IS - 3-4 SP - 175-193 ER - TY - JOUR TI - Comment on "The directionality of acoustic T-phase signals from small magnitude submarine earthquakes" [J. Acoust. Soc. Am. 119, 3669-3675 (2006)] AU - Bohnenstiehl, Delwayne R. T2 - JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA AB - In a recent paper, Chapman and Marrett [J. Acoust. Soc. Am. 119, 3669–3675 (2006)] examined the tertiary (T-) waves associated with three subduction-related earthquakes within the South Fiji Basin. In that paper it is argued that acoustic energy is radiated into the sound channel by downslope propagation along abyssal seamounts and ridges that lie distant to the epicenter. A reexamination of the travel-time constraints indicates that this interpretation is not well supported. Rather, the propagation model that is described would require the high-amplitude T-wave components to be sourced well to the east of the region identified, along a relatively flat-lying seafloor. DA - 2007/3// PY - 2007/3// DO - 10.1121/1.2435982 VL - 121 IS - 3 SP - 1293-1296 SN - 1520-8524 ER - TY - JOUR TI - Calibrating WEPP model parameters for erosion prediction on construction sites AU - Moore, A.D. AU - McLaughlin, R.A. AU - Mitasova, H. AU - Line, D.E. T2 - Transactions of the ASABE AB - Soil erosion on construction sites can be many times greater than on agricultural fields, yet there has been little modeling done for construction conditions. The objective of our study was to calibrate management and soil parameters in the agriculturally based model Water Erosion Prediction Project (WEPP) for construction and post-construction site conditions. Data from a 4 ha watershed at various stages of construction in Wake County, North Carolina, were used to compare model results with measured runoff volume and sediment yields. Model simulations were performed in GeoWEPP, a geospatial interface designed for WEPP that operates within ArcView GIS. Model parameters were adjusted from WEPP default parameters as supported by the literature and site observations. Predicted values were regressed against field data for Nash-Sutcliffe model efficiency (NSE), with NSE > 0.50 regarded as satisfactory performance. We were able to generate runoff and sediment yields comparable to observed values by replacing soil surface properties with subsoil properties, in conjunction with the cutslope management parameter file in WEPP. We found a similar agreement between predicted and observed values for stabilized conditions by increasing critical shear stress from 0.3 to 10 Pa for the soil input layer. In addition, changes to the model source code to reduce the lower limit of effective hydraulic conductivity (Kef) for impermeable surfaces resulted in improved runoff NSE, but consequently increased sediment yield on areas with higher Kef values. WEPP has great potential for modeling applications on construction sites; however, more validation studies are needed to confirm and expand upon our findings. DA - 2007/// PY - 2007/// DO - 10.13031/2013.22639 VL - 50 IS - 2 SP - 507-516 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34347247693&partnerID=MN8TOARS ER - TY - JOUR TI - A seasonal statistical evaluation of COAMPS((R)) over the arabian gulf region AU - Eager, R. E. AU - Raman, S. AU - Holt, T. R. AU - Westphal, D. AU - Reid, J. AU - Nachamkin, J. AU - Liu, M. AU - Al Mandoos, A. T2 - Pure and Applied Geophysics AB - A statistical evaluation of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) was performed over the Arabian Gulf region for the period, 1 August to 5 October, 2004. Verification skill scores of bias and root-mean-square error were estimated for surface variables and for vertical profiles to investigate any diurnal variations. The model predictions of boundary-layer heights are compared with the observations at Abu Dhabi, United Arab Emirates. The Middle East presents challenges to numerical weather prediction due to complex land-ocean-land mesoscale processes. An independent data set of surface measurements from 50 stations in the UAE was available from the Department of Water Resources Studies, Abu Dhabi for model verification. The results indicate a diurnal variation in the model errors. The errors are small considering the magnitudes of the observed variables. Errors in the coastal region can be attributed to the differences in the timing of the onset of sea and land breeze circulations in the simulations as compared to the observations. Errors are relatively smaller in the offshore locations. DA - 2007/// PY - 2007/// DO - 10.1007/978-3-7643-8493-7_17 VL - 164 IS - 8-9 SP - 1747-1764 ER - TY - JOUR TI - Simulated convective lines with parallel stratiform precipitation. Part II: Governing dynamics and associated sensitivities AU - Parker, Matthew D. T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract This article is the second of two describing convective lines with parallel stratiform (PS) precipitation. The PS mode appears to be the preferred organizational structure in environments with line-parallel vertical wind shear. This paper presents a detailed analysis of the processes that lead to the development of the PS structure within line-parallel shear, and the positive and negative feedbacks associated with the mature PS structure. As well, the particular importance of line-perpendicular and line-parallel wind shear, line-end effects, inertial stability, and patterns of convective initiation are investigated through a battery of sensitivity tests. Convective lines with PS precipitation develop in environments with both significant line-perpendicular and line-parallel vertical wind shear. Although the studied environments are initially supportive of supercells, the merging of outflows soon renders a predominant linear forcing and the characteristic PS structure. The systems’ linearity in the presence of along-line wind shear makes the local wind field more dependent upon the mesoscale structure of the convective system. For example, the along-line transport of hydrometeors is required for the development of a line-parallel precipitation region, and yet this transport does not occur immediately down the convective line’s axis because it is interrupted by the pressure maxima associated with other convective cells that are farther down the line. However, the along-line flow within the line’s leading and trailing anvils is able to contribute substantially because there are along-line pressure gradient accelerations associated with the tilted mesoscale structure of the system’s buoyancy field. This paper concludes the study by synthesizing its dynamical and sensitivity analyses with the overarching structures described in the companion article, yielding perhaps the first consolidated view of these little-studied systems. DA - 2007/2// PY - 2007/2// DO - 10.1175/JAS3854.1 VL - 64 IS - 2 SP - 289-313 SN - 1520-0469 ER - TY - JOUR TI - Simulated convective lines with parallel stratiform precipitation. Part I: An archetype for convection in along-line shear AU - Parker, Matthew D. T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract This article, the first of two describing convective lines with parallel stratiform (PS) precipitation, addresses the basic kinematic and precipitation features of these systems. The PS mode appears to be the preferred organizational structure in environments with line-parallel vertical wind shear. This archetype for long-lived convective systems has received relatively little attention to date, and yet it is frequently implicated in flash flooding because it entails both the along-line movement of hydrometeors and back-building convective development. As a reality check, this paper presents conventional observations of the wind and reflectivity fields associated with an archetypal PS system from 2 May 1997. Thereafter, analyses of idealized numerical simulations serve as the basis for a more detailed investigation of PS systems’ internal structures and processes. The observations and simulations suggest several unique aspects of the PS structure. The environment’s vertically sheared 3D wind profile helps to explain PS systems’ tendency to back-build, develop line-parallel precipitation, and evolve asymmetrically. Along-line flow within the system cold pool entails back-building on both the mesoscale and the convective scale. As well, along-line flow in the upper troposphere within the system entails along-line hydrometeor transports, especially in the leading and trailing anvils. These behaviors lead to the archetypal PS structure. Along-line hydrometeor advection means that much of the system’s precipitation falls very near its outflow boundary, and that the convective cells can seed other updrafts farther down the line. As a result, PS systems in line-parallel shear can intensify their cold pools quite rapidly. As well, in time the PS structure is characterized by diminished upper-tropospheric along-line flow within its axis. These factors may hasten transition toward a predominantly rearward-sloped updraft and the production of trailing precipitation. Even in the absence of Coriolis accelerations, this evolutionary pathway leads to highly asymmetric structures, such as are commonly observed in midlatitudes. The present introductory exposition of PS systems in deep tropospheric line-parallel wind shear sets the stage for a detailed investigation of their dynamics and sensitivities in a companion article. DA - 2007/2// PY - 2007/2// DO - 10.1175/JAS3853.1 VL - 64 IS - 2 SP - 267-288 SN - 1520-0469 ER - TY - JOUR TI - Radar characteristics of precipitation features in the EPIC and TEPPS regions of the East Pacific AU - Cifelli, R. AU - Nesbitt, S. W. AU - Rutledge, S. A. AU - Petersen, W. A. AU - Yuter, S. T2 - MONTHLY WEATHER REVIEW AB - Abstract Ship-based radar data are used to compare the structure of precipitation features in two regions of the east Pacific where recent field campaigns were conducted: the East Pacific Investigation of Climate Processes in the Coupled Ocean–Atmosphere System (EPIC-2001; 10°N, 95°W) in September 2001 and the Tropical Eastern Pacific Process Study (TEPPS; 8°N, 125°W) in August 1997. Corresponding July–September 1998–2004 Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) data are also used to provide context for the field campaign data. An objective technique is developed to identify precipitation features in the ship and TRMM PR data and to develop statistics on horizontal and vertical structure and precipitation characteristics. Precipitation features were segregated into mesoscale convective system (MCS) and sub-MCS categories, based on a contiguous area threshold of 1000 km2 (these features were required to have at least one convective pixel), as well as an “other” (NC) category. Comparison of the satellite and field campaign data showed that the two datasets were in good agreement for both regions with respect to MCS features. Specifically, both the satellite and ship radar data showed that approximately 80% of the rainfall volume in both regions was contributed by MCS features, similar to results from other observational datasets. EPIC and TEPPS MCSs had similar area distributions but EPIC MCSs tended to be more vertically developed and rain heavier than their TEPPS counterparts. In contrast to MCSs, smaller features (NCs and sub-MCSs) sampled by the ship radar in both regions showed important differences compared with the PR climatology. In the EPIC field campaign, a large number of small (&lt;100 km2), shallow (radar echo tops below the melting level) NCs and sub-MCSs were sampled. A persistent dry layer above 800 mb during undisturbed periods in EPIC may have been responsible for the high occurrence of these features. Also, during the TEPPS campaign, sub-MCSs were larger and deeper with respect to the TRMM climatology, which may have been due to the higher than average SSTs during 1997–98 when TEPPS was conducted. Despite these differences, it was found that for sizes greater than about 100 km2, EPIC precipitation features had 30-dBZ echos at higher altitudes and also had higher rain rates than similar sized TEPPS features. These results suggest that ice processes play a more important role in rainfall production in EPIC compared with TEPPS. DA - 2007/4// PY - 2007/4// DO - 10.1175/MWR3340.1 VL - 135 IS - 4 SP - 1576-1595 SN - 1520-0493 ER - TY - JOUR TI - Potential population and economic consequences of sublethal injuries in the spiny lobster fishery of the Florida Keys AU - Parsons, D. M. AU - Eggleston, D. B. T2 - MARINE AND FRESHWATER RESEARCH AB - Animals that interact with but are not retained by fishing gears may later die. The population and economic consequences of these sublethal fishery interactions are seldom known but may be significant. In the present study, a population model was used to quantify potential population and economic consequences of injuries that Caribbean spiny lobsters (Panulirus argus) sustain from fishing activities in the Florida Keys, USA. Injuries generated by the fishery are known to reduce growth and elevate mortality. Simulation modelling results indicated that injuries may reduce adult lobster abundance and associated landings by ≥50% in areas with high recreational fishing effort. When simulated injuries were ~20 times lower (representing areas with lower fishing effort), these injuries were only responsible for a 5 and 8% reduction in the adult lobster population and commercial landings respectively. Important parameters within the model (growth, time in stage and mortality of injured lobsters) were altered by ±10% to assess model sensitivity. Final results changed <10% (with the exception of one 15% change), suggesting that model output was relatively insensitive to variation in key parameters. When the impact of sublethal injuries was applied to the entire spiny lobster fishery in the Florida Keys, adult stock biomass and annual commercial landings were reduced by 900 and 160 t (US$1.6 million) respectively. These results suggest that sublethal fishery interactions can lead to high population and economic losses, and highlight the need to incorporate sublethal injuries into stock assessments and economic models. DA - 2007/// PY - 2007/// DO - 10.1071/MF06149 VL - 58 IS - 2 SP - 166-177 SN - 1323-1650 KW - Caribbean spiny lobster KW - Florida Keys KW - individual based model KW - Panulirus argus KW - recreational fishing KW - sublethal injury ER - TY - JOUR TI - On coastal ocean systems, coupled model architectures, products and services: Morphing from observations to operations and applications AU - Pietrafesa, L. J. AU - Buckley, E. B. AU - Peng, M. AU - Bao, S. AU - Liu, H. AU - Peng, S. AU - Xie, L. AU - Dickey, D. A. T2 - MARINE TECHNOLOGY SOCIETY JOURNAL AB - The national build-up of “coastal ocean observing systems” (COOSs) to establish the coastal observing component of the national component of the Integrated Ocean Observing System (IOOS) network must be well organized and must acknowledge, understand and address the needs of the principal clients, the federal, and in some cases state as well, agencies that provide financial support if it is to have substantive value. The funds being spent in support of COOS should be invested in pursuit of the establishment of the National Backbone (NB) that is needed: to greatly improve atmospheric, oceanic and coastal “weather” forecasting, broadly defined; for ecosystem management; and to document climate variability and change in coastal zones. However, this process has not occurred in a well conceived, orderly, well integrated manner due to historical and cultural bases and because of local priorities. A sub-regional effort that is designed to meet federal agency needs and mission responsibilities with an emphasis on meeting societal needs is presented by way of example to show that university and industry partners with federal agencies have an important role to play in the future of building out ocean and coastal observing and prediction systems and networks. DA - 2007/// PY - 2007/// DO - 10.4031/002533207787442268 VL - 41 IS - 1 SP - 44-52 SN - 1948-1209 ER - TY - JOUR TI - Dispersal dynamics of post-larval blue crabs, Callinectes sapidus, within a wind-driven estuary AU - Reyns, N. B. AU - Eggleston, David AU - Luettich, R. A. T2 - Fisheries Oceanography DA - 2007/// PY - 2007/// DO - 10.1111/j.1365-2419.2006.00420.x VL - 16 IS - 3 SP - 257–272 ER - TY - JOUR TI - Consistency of interdecadal variation in the summer monsoon over eastern China and heterogeneity in springtime surface air temperatures AU - Xu, Xiangde AU - Shi, Xiaohui AU - Xie, Lian AU - Wang, Yafei T2 - JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN AB - This study investigates the consistency of interdecadal variations in the East Asian summer monsoon (EASM) and changes in the heterogeneous structure of sealland springtime surface air temperature (SAT) over eastern China and the adjacent ocean (including the South China Sea and part of the Western Pacific Ocean). A profile of the summer mean meridional wind over eastern China for the past 40 years shows a coherent interdecadal weakening trend for the EASM. The decadal-scale (11-year running mean) summertime (June-August) wind and springtime (March-May) SAT fields are decomposed using the empirical orthogonal function (EOF) method. The results indicate that both the leading eigen-vector of the decadal-scale meridional wind and that for the SAT over East Asia account for more than 70% of the total variance. Their time coefiicients show a similar trend, with the transition from negative to positive values occurring around 1978; i.e., the EASM turned from a stronger phase to a weaker phase around 1978. The springtime sealland SAT distribution before and after 1978 also showed a shift in interdecadal trends. Therefore, the south-lowlnorth-high nature of the principal component of springtime SAT over eastern China is closely related to the progressive weakening of the EASM. Our results suggest that within the context of the regional impact of global climate change, heterogeneous changes in the regional springtime sea/land SAT in eastern Asia might in part have led to a weakening of the effect of sealland thermal driving on the EASM. DA - 2007/2// PY - 2007/2// DO - 10.2151/jmsj.85A.311 VL - 85A SP - 311-323 SN - 2186-9057 ER - TY - JOUR TI - A unique Yellow River-derived distal subaqueous delta in the Yellow Sea AU - Yang, Z.S. AU - Liu, J.P. T2 - Marine Geology AB - Newly acquired high-resolution Chirp sonar profiles reveal a unique Yellow River-derived, alongshore distributed, bidirectional (landward and seaward) across-shelf transported, omega-shaped (“Ω”) distal subaqueous deltaic lobe deposited around the eastern tip of the Shandong Peninsula in the Yellow Sea. This clinoform deposit directly overlies the postglacial transgressive surface, featured by convex-up seafloor morphology, up to 40 m thick locally. Radiocarbon-14 dates from the underlain pre-Holocene and transgressive sediments indicate this distal lobe has formed since the middle-Holocene highstand under a relatively stable sea level. This along-shelf distributed distal clinoform has been deposited mainly by the resuspended Yellow River sediments carried down by the coastal current, interacting with the local waves, tides and upwelling. Collectively, over the past 7000 years, nearly 30% of the Yellow River-derived sediment has been re-suspended and transported out of the Bohai Sea into the Yellow Sea. Overall, the Yellow River-derived sediment could reach the − 80 m water depth in the central South Yellow Sea, about 700 km from the river mouth; in contrast, a very small fraction of the modern riverine sediment could escape the outer shelf or reach the Okinawa Trough. DA - 2007/6// PY - 2007/6// DO - 10.1016/j.margeo.2007.02.008 VL - 240 IS - 1-4 SP - 169-176 J2 - Marine Geology LA - en OP - SN - 0025-3227 UR - http://dx.doi.org/10.1016/j.margeo.2007.02.008 DB - Crossref KW - Yellow River KW - Yellow Sea KW - longshore transport KW - clinoform KW - subaqueous delta ER - TY - JOUR TI - A convective line with leading stratiform precipitation from BAMEX AU - Storm, Brandon A. AU - Parker, Matthew D. AU - Jorgensen, David P. T2 - MONTHLY WEATHER REVIEW AB - Abstract On 31 May 2003, a front-fed convective line with leading stratiform precipitation (FFLS) was observed during the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX). The high-resolution BAMEX measurements provided one of the first opportunities to thoroughly observe the characteristics of an FFLS system. The 31 May system had an overturning updraft during its early stages, and produced leading stratiform precipitation. As the system matured, a jump updraft developed and the system began to produce trailing stratiform precipitation. It appears that this transition was facilitated by a local decrease in the low-level line-perpendicular vertical wind shear over time, as well as an increase in the surface cold pool’s strength. The BAMEX data further help to address the question of how FFLS systems can be long lived when their inflow passes through the line-leading precipitation: preline soundings suggest a destabilization mechanism resulting from the vertical profile of cooling within the leading stratiform precipitation. This destabilization also helps to explain the 31 May convective system’s persistence in an environment with very low CAPE. DA - 2007/5// PY - 2007/5// DO - 10.1175/MWR3392.1 VL - 135 IS - 5 SP - 1769-1785 SN - 0027-0644 ER - TY - JOUR TI - Chemical sensor networks for the aquatic environment AU - Johnson, Kenneth S. AU - Needoba, Joseph A. AU - Riser, Stephen C. AU - Showers, William J. T2 - CHEMICAL REVIEWS AB - ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical Sensor Networks for the Aquatic EnvironmentKenneth S. Johnson, Joseph A. Needoba, Stephen C. Riser, and William J. ShowersView Author Information Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, California 95039, School of Oceanography, University of Washington, Seattle, Washington 98195-7940, Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695 Cite this: Chem. Rev. 2007, 107, 2, 623–640Publication Date (Web):January 24, 2007Publication History Received14 July 2006Published online24 January 2007Published inissue 1 February 2007https://doi.org/10.1021/cr050354eCopyright © 2007 American Chemical SocietyRequest reuse permissionsArticle Views2963Altmetric-Citations139LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (1 MB) Get e-AlertscloseSUBJECTS:Anions,Electrodes,Fluxes,Oxygen,Sensors Get e-Alerts DA - 2007/2// PY - 2007/2// DO - 10.1021/cr050354e VL - 107 IS - 2 SP - 623-640 SN - 1520-6890 ER - TY - JOUR TI - Influence of rhizome propagule size on yields and triterpene glycoside concentrations of black cohosh [Actaea racemosa L. syn Cimicifuga racemosa (L.) Nuttal] AU - McCoy, Joe-Ann AU - Davis, Jeanine M. AU - Camper, N. Dwight AU - Khan, Ikhlas AU - Bharathi, Avula T2 - HORTSCIENCE AB - Black cohosh [ Actaea racemosa L. syn. Cimicifuga racemosa (L.) Nuttal] is a native North American medicinal plant traditionally harvested for its rhizomes and roots. Black cohosh products were listed in the top 10 selling herbal supplements from 2002 to 2005. As a result of increasing commercial demand, there is a need to develop propagation protocols suitable for production purposes to replace current methods of harvesting from wild populations. The objectives of this study were to 1) determine optimal rhizome propagule division size for successful regeneration, 2) analyze triterpene glycoside concentrations, 3) quantify survival rates after 3 years of production, and 4) evaluate net yield results. Experimental sites included a shade cloth structure in an agricultural research field, a shaded forest interior, and a shaded, disturbed forest edge. Plant emergence, growth, and survival were assessed at each site over a 3-year period. Optimal rhizome division size for propagation was a 10 to 30-g section originating from terminal rhizome portions. Rhizome survival averaged 97% among all treatments tested by year 3 at three sites. No differences in mean triterpene glycoside concentrations were detected between rhizome size classes or sites tested. Mean cimiracemoside concentrations ranged from 0.80 to 1.39 mg·g –1 d/w tissue, deoxyactein 0.47 to 0.92 mg·g –1 , and actein 10.41 to 13.69 mg·g –1 . No differences in triterpene levels were detected between flowering and nonflowering plants, nor were yields reduced. Net yields from a shade cloth production site were 9 and 17 times higher than a disturbed forest edge and forest site respectively. Black cohosh is a strong candidate for commercial propagation under adequate site selection. DA - 2007/2// PY - 2007/2// DO - 10.21273/hortsci.42.1.61 VL - 42 IS - 1 SP - 61-64 SN - 0018-5345 KW - propagation KW - rhizome divisions KW - habitat KW - actein KW - deoxyactein KW - cimiracemoside ER - TY - JOUR TI - Impacts of waste from concentrated animal feeding operations on water quality AU - Burkholder, JoAnn AU - Libra, Bob AU - Weyer, Peter AU - Heathcote, Susan AU - Kolpin, Dana AU - Thorne, Peter S. AU - Wichman, Michael T2 - ENVIRONMENTAL HEALTH PERSPECTIVES AB - Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This work-group, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards--Searching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems. DA - 2007/2// PY - 2007/2// DO - 10.1289/ehp.8839 VL - 115 IS - 2 SP - 308-312 SN - 1552-9924 KW - ecology KW - human health KW - poultry KW - swine KW - water contaminants KW - wildlife ER - TY - JOUR TI - A comparison of blue crab and bivalve delta N-15 tissue enrichment in two North Carolina estuaries AU - Bucci, J. P. AU - Rebach, S. AU - Demaster, D. AU - Showers, W. J. T2 - Environmental Pollution AB - Stable isotope analyses (delta(15)N) were used to examine invertebrate tissue enrichment in two North Carolina estuaries with differing amounts of nutrient loading. Bivalves collected from a nutrient sensitive estuary yielded a significant difference in mean nitrogen isotopic composition of tissue (10.4 per thousand+/-0.82; N=66) compared to bivalves collected from a less nutrient sensitive estuary (6.4 per thousand+/-0.63; N=45). Similarly, blue crabs from nutrient sensitive sites had a nitrogen isotopic composition of 11.4 per thousand (+/-1.3, N=77), which was significantly different (P<0.001) than the tissue of less nutrient sensitive blue crabs (9.6 per thousand+/-0.6; N=77). The results showed that an inverse relationship exists between invertebrate tissue enrichment and indicators of water quality across estuarine sites. This study suggests that a relationship may exist between nutrient sources and subsequent energy transfer to estuarine consumers in two North Carolina estuaries. DA - 2007/// PY - 2007/// DO - 10.1016/j.envpol.2006.03.009 VL - 145 IS - 1 SP - 299-308 ER - TY - JOUR TI - Water quality gradients across Albemarle-Pamlico estuarine system: Seasonal variations and model applications AU - Lin, Jing AU - Xie, Lian AU - Pietrafesa, Leonard J. AU - Ramus, Joseph S. AU - Paerl, Hans W. T2 - JOURNAL OF COASTAL RESEARCH AB - The seasonal variations of water quality parameters as nitrite plus nitrate (NO−;x), total phosphate (PO3−4), chlorophyll a (chl a), and dissolved oxygen (DO) are analyzed across the Croatan-Roanoke-Albemarle-Pamlico-Core Sounds estuarine system (CAPES). Overall, several patterns are observed: The Chowan-Roanoke-Albemarle system is generally phosphorous limiting for phytoplankton growth, whereas both the Tar-Pamlico and the Neuse Rivers are generally nitrogen limiting. The largest PO3−4 gradients exist in the upstream portion of the Albemarle Sound, and the largest NO−x gradients exist in the lower Neuse and the Tar-Pamlico Rivers. Dissolved oxygen appears to have the strongest seasonal signal among the water quality variables, with highest DO values observed during winter (within the CAPES and in the nearshore area) or spring (in the continental shelf and deeper ocean) and lowest during summer. Chlorophyll a concentrations are highest during spring (within the CAPES) or winter (offshore). In contrast, the NOx− and PO3−4 concentrations in both the Tar-Pamlico and Neuse River estuaries are usually higher during the second half of the year. The time differences of the peak nutrient and chl a concentrations suggest that highest algal growth rate (and hence nutrient uptake rate) occurs during spring, and the consumed nutrients are released to the water column through a nutrient recycling method later in the year. A coupled three-dimensional hydrodynamic water quality model is then applied to the entire system. The general model setup and parameter derivation of the model is presented here. The basic observed water quality characteristics such as the nutrient limiting pattern and the spatial gradients across the system are reproduced in the model. The model results also suggest that nutrient fluxes, generated from the diagenesis of deposited organic matter and released from the sediment bed, could be an important mechanism for nutrient recycling in the region. DA - 2007/1// PY - 2007/1// DO - 10.2112/05-0507.1 VL - 23 IS - 1 SP - 213-229 SN - 1551-5036 KW - nutrient KW - chlorophyll a KW - dissolved oxygen KW - Neuse River KW - Pamlico Sound ER - TY - JOUR TI - Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present AU - Schweitzer, Mary Higby AU - Wittmeyer, Jennifer L. AU - Horner, John R. T2 - PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES AB - Soft tissues and cell-like microstructures derived from skeletal elements of a well-preserved Tyrannosaurus rex (MOR 1125) were represented by four components in fragments of demineralized cortical and/or medullary bone: flexible and fibrous bone matrix; transparent, hollow and pliable blood vessels; intravascular material, including in some cases, structures morphologically reminiscent of vertebrate red blood cells; and osteocytes with intracellular contents and flexible filipodia. The present study attempts to trace the occurrence of these four components in bone from specimens spanning multiple geological time periods and varied depositional environments. At least three of the four components persist in some skeletal elements of specimens dating to the Campanian. Fibrous bone matrix is more altered over time in morphology and less likely to persist than vessels and/or osteocytes. Vessels vary greatly in preservation, even within the same specimen, with some regions retaining pliability and other regions almost crystalline. Osteocytes also vary, with some retaining long filipodia and transparency, while others present with short and stubby filipodia and deeply pigmented nuclei, or are pigmented throughout with no nucleus visible. Alternative hypotheses are considered to explain the origin/source of observed materials. Finally, a two-part mechanism, involving first cross-linking of molecular components and subsequent mineralization, is proposed to explain the surprising presence of still-soft elements in fossil bone. These results suggest that present models of fossilization processes may be incomplete and that soft tissue elements may be more commonly preserved, even in older specimens, than previously thought. Additionally, in many cases, osteocytes with defined nuclei are preserved, and may represent an important source for informative molecular data. DA - 2007/1/22/ PY - 2007/1/22/ DO - 10.1098/rspb.2006.3705 VL - 274 IS - 1607 SP - 183-197 SN - 1471-2954 KW - dinosaur KW - soft tissues KW - red blood cells KW - osteocytes KW - vessels KW - preservation ER - TY - JOUR TI - Salmonella Populations and Prevalence in Layer Feces from Commercial High-Rise Houses and Characterization of the Salmonella Isolates by Serotyping, Antibiotic Resistance Analysis, and Pulsed Field Gel Electrophoresis AU - Li, X. AU - Payne, J.B. AU - Santos, F.B. AU - Levine, J.F. AU - Anderson, K.E. AU - Sheldon, B.W. T2 - Poultry Science AB - Salmonella species are recognized as a major cause of foodborne illnesses that are closely associated with the consumption of contaminated poultry and egg products. The objectives of this study were to evaluate the Salmonella populations and prevalence in layer feces during the laying cycle and molting of the hen and to characterize the layer fecal Salmonella isolates by serotyping, antibiotic resistance analysis, and pulsed field gel electrophoresis. Fecal samples were collected from a commercial layer complex consisting of 12 houses. Composite fecal samples across each row were collected as a function of bird age [18 wk (at placement), 25 to 28 wk (first peak of production cycle), 66 to 74 wk (molting), and 75 to 78 wk (second peak of production cycle)]. Bird ages and molting practice did not significantly affect (P > 0.05) Salmonella populations with an average of 1.25, 1.27, 1.20, and 1.14 log most probable number/g for the 18-, 25- to 28-, 66- to 74-, and 75- to 7-wk birds, respectively. However, the 18-wk birds had the highest prevalence of Salmonella (55.6%), followed by the 25- to 28-wk birds (41.7%), 75- to 78-wk birds (16.7%), and 66- to 74-wk birds (5.5%). Of the 45 Salmonella isolates characterized, the most predominant serovar was Salmonella Kentucky (62%). Thirty-five percent of the Salmonella isolates were resistant to at least 1 antibiotic. As expected, considerable genetic diversity was observed within and across the different serovars. DA - 2007/3// PY - 2007/3// DO - 10.1093/ps/86.3.591 VL - 86 IS - 3 SP - 591-597 J2 - Poultry Science LA - en OP - SN - 0032-5791 UR - http://dx.doi.org/10.1093/ps/86.3.591 DB - Crossref KW - Salmonella KW - layer feces KW - population KW - prevalence KW - characterization ER -