TY - BOOK TI - BOOK REVIEW: Hiking Washington’s Geology by Scott Babcock and Bob Carson AU - Wegmann, K.W. AU - Babcock, Scott AU - Carson, Bob DA - 2001/// PY - 2001/// VL - 28 SE - 28 ER - TY - JOUR TI - q 2002 American Meteorological Society Tides on the West Florida Shelf AU - He, Ruoying AU - Robert AU - Weisberg, H. DA - 2001/// PY - 2001/// UR - http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.665.7889 N1 - The principal semidiurnal (M2 and S2) and diurnal (K1 and O1) tidal constituents are described on the west Florida continental shelf (WFS) using a combination of in situ measurements and a three-dimensional, primitive equation numerical model. The measurements are of sea level and currents along the coastline and across the shelf, respectively. The model extends from west of the Mississippi River to the Florida Keys with an open boundary arcing between. It is along this open boundary that the regional model is forced by a global tide model. Standard barotropic tidal analyses are performed for both the data and the model, and quantifiable metrics are provided for comparison. Based on these comparisons, the authors present coamplitude and cophase charts for sea level and velocity hodographs for currents. The semidiurnal constituents show marked spatial variability, whereas the diurnal constituents are spatially more uniform. Apalachicola Bay is a demarcation point for the semidiurnal tides that are well developed to the southeast along the WFS but are minimal to the west. The largest semidiurnal tides are in the Florida Big Bend and Florida Bay regions with a relative minimum in between just to the south of Tampa Bay. These spatial distributions may be explained on the basis of local geometry. A Lagrangian Stokes drift, coherently directed toward the northwest, is identified but is of relatively small magnitude when compared with the potential for particle transport by seasonal and synoptic-scale forcing. Bottom stress-induced tidal mixing is examined and estimates are made of the bottom logarithmic layer height by the M2 tidal currents. 1. RN - The principal semidiurnal (M2 and S2) and diurnal (K1 and O1) tidal constituents are described on the west Florida continental shelf (WFS) using a combination of in situ measurements and a three-dimensional, primitive equation numerical model. The measurements are of sea level and currents along the coastline and across the shelf, respectively. The model extends from west of the Mississippi River to the Florida Keys with an open boundary arcing between. It is along this open boundary that the regional model is forced by a global tide model. Standard barotropic tidal analyses are performed for both the data and the model, and quantifiable metrics are provided for comparison. Based on these comparisons, the authors present coamplitude and cophase charts for sea level and velocity hodographs for currents. The semidiurnal constituents show marked spatial variability, whereas the diurnal constituents are spatially more uniform. Apalachicola Bay is a demarcation point for the semidiurnal tides that are well developed to the southeast along the WFS but are minimal to the west. The largest semidiurnal tides are in the Florida Big Bend and Florida Bay regions with a relative minimum in between just to the south of Tampa Bay. These spatial distributions may be explained on the basis of local geometry. A Lagrangian Stokes drift, coherently directed toward the northwest, is identified but is of relatively small magnitude when compared with the potential for particle transport by seasonal and synoptic-scale forcing. Bottom stress-induced tidal mixing is examined and estimates are made of the bottom logarithmic layer height by the M2 tidal currents. 1. ER - TY - CONF TI - Real Time Monitoring and Circulation Modeling on the West Florida Shelf AU - Weisberg, RH AU - He, R AU - Luther, M C2 - 2001/// C3 - AGU Fall Meeting Abstracts DA - 2001/// ER - TY - BOOK TI - Modeling Dynamic Climate Systems AU - Robinson, W.A. T2 - Modeling Dynamic Systems DA - 2001/// PY - 2001/// DO - 10.1007/978-1-4613-0113-4 PB - Springer SN - 9780387951348 9781461265306 9781461301134 ER - TY - JOUR TI - Where's the-heat? Insights from GCM experiments into the lack of Eastern US warming AU - Robinson, WA AU - AMS T2 - 12th Symposium on Global Change and Climate Variations DA - 2001/// PY - 2001/// SP - 5-6 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000177601900002&KeyUID=WOS:000177601900002 ER - TY - JOUR TI - Relationships between atmospheric internal variability and the responses to an extratropical SST anomaly AU - Peng, SL AU - Robinson, WA T2 - Journal of Climate AB - The January and February responses of a GCM to an imposed extratropical Pacific SST anomaly are compared with the patterns of the model's internal variability. Relevant patterns of internal variability are diagnosed from ensembles of model control runs by regressing monthly mean geopotentials and temperatures against low-level temperatures in the vicinity of the SST anomaly and by EOF analysis. These patterns are found to play a significant role in determining the local and the remote responses to the SST anomaly. Different responses to the SST anomaly in the GCM's January and February climates are largely explained by the differences in the regression patterns and in the leading EOF. The GCM response may be considered as comprising a direct linear response to low-level heating, that is local to the forcing and baroclinic, and an eddy-forced component that closely resembles patterns of the model's internal variability—it is equivalent barotropic and extends over the entire hemisphere. The results suggest that for a warm SST anomaly over the Kuroshio Extension to induce an equivalent-barotropic ridge immediately east of the anomaly, the internal variability must have a well-defined center of action over the central Pacific. In this GCM, this is nearly true in February but not in January. Similar analyses are performed for the observed flow to determine the patterns of variability in nature and thereby to suggest the potential response to SST forcing. The natural variability in January and February has a strong large-scale center over the Pacific, which, according to the model results, should favor the development of an equivalent-barotropic ridge in response to a warm SST anomaly. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0442(2001)014<2943:RBAIVA>2.0.CO;2 VL - 14 IS - 13 SP - 2943-2959 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000169796600010&KeyUID=WOS:000169796600010 ER - TY - JOUR TI - Vertical distribution of oxides of nitrogen in the semi-urban planetary boundary layer: Mixing ratios, sources and transport AU - Moore, T.C. AU - Sullivan, L.J. AU - Roelle, P.A. AU - Aneja, V.P. T2 - Chemosphere - Global Change Science AB - Measurements of the mixing ratios of tropospheric NO and NOY (defined as nitric oxide (NO) + nitrogen dioxide (NO2) + peroxyacetyl nitrate (PAN) + nitric acid (HNO3) + particulate nitrate (NO3−) + ⋯) were made over a semi-urban area of central North Carolina at the surface (10 m) and on a tower at heights of 250 m (820 ft) and 433 m (1420 ft) above ground level (AGL) from December 1994 to February 1995. These measurements were compared with synoptic weather data and regional and local upper air soundings in an effort to characterize NO and NOY in the planetary boundary layer in terms of their vertical distributions, diurnal profile, and related transport mechanisms. A pronounced decreasing vertical gradient in both NO and NOY mixing ratios was observed, with a distinct diurnal cycle and nocturnal minimum. Furthermore, the results suggest that NO and NOY were mixed upward from the surface during passage of synoptic meteorological features (and their associated vertical motions). Most importantly, the data reveals that mixing ratios of NO and NOY at the elevated heights did not exist in sufficient concentrations above the inversion layer in the nocturnal boundary layer to be mixed downward upon breakup of the nocturnal inversion and affect surface measurements. Instead, concentrations of NO and NOY were apparently mixed upward during the morning and midday hours by vertical boundary layer processes. Thus, the association of observed increases in surface NO and NOY mixing ratios based solely on downward mixing processes is not justified in all cases, and other sources and processes for these increases must be considered, particularly over rural areas. DA - 2001/// PY - 2001/// DO - 10.1016/S1465-9972(00)00028-3 VL - 3 IS - 1 SP - 7-23 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0033668009&partnerID=MN8TOARS ER - TY - MGZN TI - Highway runoff effects on Freshwater Mussel Health AU - Levine, J.F. T2 - Centerline: Environmental Quarterly Newsletter DA - 2001/10// PY - 2001/10// SP - 7 PB - NC Department of Transportation ER - TY - CONF TI - Hemolymph Collection in Elliptio complanata AU - Gustafson, L. AU - Levine, J.F. AU - Bogan, A. AU - Showers, W. AU - Hanlon, S. AU - Stoskopf, M. T2 - NCSU College of Veterinary Medicine Research Forum C2 - 2001/3// CY - Raleigh, NC DA - 2001/3// PY - 2001/3// ER - TY - CONF TI - Population Dynamics in Neutered and Intact Feral Cat Colonies AU - Nutter, F. AU - Levine, J.F. AU - Stoskopf, M. T2 - NCSU College of Veterinary Medicine Research Forum C2 - 2001/3// CY - Raleigh, NC DA - 2001/3// PY - 2001/3// ER - TY - CONF TI - Determination of Host Fish Species for the Propagation of Endangered Freshwater Mussels AU - Tuttle, A. AU - Hanlon, S. AU - Levine, J.F. T2 - NCSU College of Veterinary Medicine Research Forum C2 - 2001/3// CY - Raleigh, NC DA - 2001/3// PY - 2001/3// ER - TY - CONF TI - Prevalence of Bacterial Food-borne Pathogens in Shellfish AU - Tlamka, B. AU - Pitts, T. AU - Levine, J.F. AU - French, J.B. AU - Mare, CI AU - Joens, L.A. T2 - Eighty-Second Conference of Research Workers in Animal Diseases C2 - 2001/// CY - St. Louis, Missouri DA - 2001/// PY - 2001/11// ER - TY - CONF TI - A Method For Measuring Growth In Living Freshwater Mussels AU - Molina, R. AU - Levine, J.F. AU - Hanlon, S. AU - Savidge, T. AU - Bogan, A. AU - Johnson, J. T2 - Freshwater Mollusk Conservation Society Symposium C2 - 2001/3// DA - 2001/3// PY - 2001/3// ER - TY - RPRT TI - Freshwater mussels of North Carolina AU - Levine, J.F. AU - Hanlon, S. DA - 2001/// PY - 2001/// M3 - poster ER - TY - CONF TI - Affects Of Flow On Juveniles Of Lampsilis Radiata Radiata Reared In An Indoor Recirculating Culture System AU - Hanlon, S. AU - Levine, J.F. AU - Savidge, T. T2 - Freshwater Mollusk Conservation Society Symposium C2 - 2001/3// CY - Pittsburgh, PA DA - 2001/3// PY - 2001/3// ER - TY - BOOK TI - Freshwater mussels: A learning resource and activity book AU - Levine, J.F. AU - Hanlon, S. DA - 2001/// PY - 2001/// PB - N.C. Freshwater Mussel Conservation Partnership ER - TY - CONF TI - Nonlethal Hemolymph Collection for Assessing Freshwater Mollusk Health AU - Gustafson, L. AU - Levine, J.F. AU - Bogan, A. AU - Showers, W. AU - Hanlon, S. AU - Stoskopf, M. T2 - Freshwater Mussel Conservation Society Symposium C2 - 2001/3// CY - Pittsburgh, PA DA - 2001/3// PY - 2001/3// ER - TY - RPRT TI - The Life Cycle of Freshwater Mussels AU - Levine, J.F. AU - Hanlon, S AU - Bogan, A DA - 2001/// PY - 2001/// M3 - poster ER - TY - CONF TI - Use of a Multitiered Approach to Assess Health Status of Coastal North Carolina Fish AU - Law, J.M. AU - Choi, K.J. AU - Johnson, A.K. AU - Lehmann, D.W. AU - Pettengill, M. AU - Levine, J. AU - Harms, C T2 - 22nd Annual Society of Environmental Toxicology and Chemistry (SETAC) Meeting C2 - 2001/11// CY - Baltimore, Maryland DA - 2001/11// PY - 2001/11// ER - TY - THES TI - Effects of Natural Irradiance Fluctuations on the Photosynthetic Responses of Gymnodinium Breve (Karenia Brevis) and Thalassiosira Pseudonana and Hydrographic Structure Associated with Persistent Gymnodinium Breve (Karenia Brevis) Subsurface Accumulations with Implications for Red Tide Patch Information AU - Reed, R.E. DA - 2001/// PY - 2001/// M3 - Ph.D. Dissertation PB - North Carolina State University ER - TY - JOUR TI - Chemical and optical changes in freshwater dissolved organic matter exposed to solar radiation AU - Osburn, Christopher L. AU - Morris, Donald P. AU - Thorn, Kevin A. AU - Moeller, Robert E. T2 - Biogeochemistry AB - We studied the chemical and optical changes inthe dissolved organic matter (DOM) from twofreshwater lakes and a Sphagnum bog afterexposure to solar radiation. Stable carbonisotopes and solid-state 13C-NMR spectraof DOM were used together with optical andchemical data to interpret results fromexperimental exposures of DOM to sunlight andfrom seasonal observations of two lakes innortheastern Pennsylvania. Solar photochemicaloxidation of humic-rich bog DOM to smaller LMWcompounds and to DIC was inferred from lossesof UV absorbance, optical indices of molecularweight and changes in DOM chemistry. Experimentally, we observed a 1.2‰ enrichment in δ13$C and a 47% loss in aromaticC functionality in bog DOM samples exposed tosolar UVR. Similar results were observed inthe surface waters of both lakes. In latesummer hypolimnetic water in humic LakeLacawac, we observed 3 to 4.5‰enrichments in δ13C and a 30% increase inaromatic C relative to early spring valuesduring spring mixing. These changes coincidedwith increases in molecular weight and UVabsorbance. Anaerobic conditions of thehypolimnion in Lake Lacawac suggest thatmicrobial metabolism may be turning overallochthonous C introduced during springmixing, as well as autochthonous C. Thismetabolic activity produces HMW DOM during thesummer, which is photochemically labile andisotopically distinct from allochthonous DOM orautochthonous DOM. These results suggest bothphotooxidation of allochthonous DOM in theepilimnion and autotrophic production of DOM bybacteria in the hypolimnion cause seasonaltrends in the UV absorbance of lakes. DA - 2001/7// PY - 2001/7// DO - 10.1023/a:1010657428418 VL - 54 IS - 3 SP - 251-278 SN - 0168-2563 UR - http://dx.doi.org/10.1023/a:1010657428418 KW - carbon stable isotopes KW - DOM KW - humic acids KW - NMR KW - photooxidation ER - TY - JOUR TI - Field ecology of toxic Pfiesteria complex species and a conservative analysis of their role in estuarine fish kills. AU - Glasgow, H B AU - Burkholder, J M AU - Mallin, M A AU - Deamer-Melia, N J AU - Reed, R E T2 - Environmental Health Perspectives AB - Within the past decade, toxic Pfiesteria outbreaks have been documented in poorly flushed, eutrophic areas of the largest and second largest estuaries on the U.S. mainland. Here we summarize a decadal field effort in fish kill assessment, encompassing kills related to Pfiesteria (49 major kills in North Carolina estuaries since 1991 and 4 in Maryland estuaries in 1997) and to other factors such as low oxygen stress (79 major fish kills in North Carolina estuaries). The laboratory and field data considered in developing our protocols are described, including toxic Pfiesteria behavior, environmental conditions conducive to toxic Pfiesteria activity, and impacts of toxic clonal Pfiesteria on fish health. We outline the steps of the standardized fish bioassay procedure that has been used since 1991 to diagnose whether actively toxic Pfiesteria was present during estuarine fish kills. Detailed data are given for a 1998 toxic Pfiesteria outbreak in the Neuse Estuary in North Carolina to illustrate of the full suite of diagnostic steps completed. We demonstrate that our conservative approach in implicating toxic Pfiesteria involvement in fish kills has biased in favor of causes other than Pfiesteria. Data are summarized from experiments that have shown stimulation of toxic Pfiesteria strains by nutrient (N, P) enrichment, supporting field observations of highest abundance of toxic strains in eutrophic estuaries. On the basis of a decade of research on toxic Pfiesteria, we present a conceptual model of the seasonal dynamics of toxic strains as affected by changing food resources and weather patterns. We also recommend protocols and research approaches that will strengthen the science of fish kill assessment related to Pfiesteria and/or other causative factors. DA - 2001/10// PY - 2001/10// DO - 10.1289/ehp.01109s5715 VL - 109 IS - suppl 5 SP - 715-730 J2 - Environmental Health Perspectives LA - en OP - SN - 0091-6765 1552-9924 UR - http://dx.doi.org/10.1289/ehp.01109s5715 DB - Crossref ER - TY - JOUR TI - Calculation of spectral weighting functions for the solar photobleaching of chromophoric dissolved organic matter in temperate lakes AU - Osburn, Christopher L. AU - Zagarese, Horacio E. AU - Morris, Donald P. AU - Hargreaves, Bruce R. AU - Cravero, Walter E. T2 - Limnol. Oceanogr. AB - The effect of solar radiation on the dissolved absorption coefficient (λ CDOM [λ]), which reflects the concentration of chromophoric dissolved organic matter (CDOM), was investigated in several lakes near Bariloche, Argentina and in northeastern Pennsylvania, USA. Samples of 0.2 µm filtered lake water were exposed in quartz tubes to different portions of the solar spectrum using optical cutoff filters to remove parts of the ultraviolet (UV) region of the solar spectrum. Changes in the spectral absorption in these samples and the absorbed incident energy were used to calculate spectral weighting functions (SWFs) for the photobleaching (PB) of CDOM. PB was measured as the loss of α CDOM [λ] (the α CDOM [λ] was averaged from 280 to 500 nm) per unit absorbed energy. CDOM from humic and clear lakes, as well as from a Sphagnum bog and an algal culture, was used in the experiments covering a wide range of carbon sources. We used an iterative, nonlinear optimization method to fit the measured results to a simple exponential function in order to generate each SWF. Comparing individual SWFs calculated for various CDOM sources, we computed a summary SWF from the experiments using epilimnial CDOM from our study lakes. Our summary SWF was able to explain 80‐90% of the observed variance in our exposure experiments, and we were able to predict PB results obtained for other Argentine lakes (mean error 14.5%). Finally, we calculated that the effect of UV‐B radiation on PB was small (<20% of total decrease in the absorption coefficient) compared to UVA and blue light radiation. This suggested that increased UV‐B radiation due to stratospheric ozone depletion would not greatly increase the photobleaching of whole water column CDOM in Patagonian lakes (<10%). DA - 2001/8// PY - 2001/8// DO - 10.4319/lo.2001.46.6.1455 VL - 46 IS - 6 SP - 1455-1467 ER - TY - JOUR TI - Landslide hazard mapping in Cowlitz County: a progress report AU - Wegmann, K. W. AU - Walsh, T. J. T2 - Washington Geology DA - 2001/// PY - 2001/// VL - 29 IS - 1-2 SP - 30-33 ER - TY - JOUR TI - An evolution of collaboratives within a University: A conversation among colleagues AU - Owens, K. AU - Broadway, F. AU - Foos, A. AU - McConnell, D. A. T2 - Electronic Journal of Science Education DA - 2001/// PY - 2001/// VL - 6 ER - TY - JOUR TI - Evaluation of potential health risks to Eastern Elliptio (Elliptio complanata) (Mollusca: Bivalvia: Unionida: Unionidae) and implications for sympatric endangered freshwater mussel species AU - Chittick, B. AU - Stoskopf, M. AU - Law, M. AU - Overstreet, R. AU - Levine, J. T2 - Journal of Aquatic Ecosystem Stress and Recovery DA - 2001/// PY - 2001/// VL - 9 IS - 1 SP - 35 ER - TY - JOUR TI - Evaluation of aerosol direct radiative forcing in MIRAGE AU - Ghan, S AU - Laulainen, N AU - Easter, R AU - Wagener, R AU - Nemesure, S AU - Chapman, E AU - Zhang, Y AU - Leung, R T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - A variety of measurements have been used to evaluate the treatment of aerosol radiative properties and radiative impacts of aerosols simulated by the Model for Integrated Research on Atmospheric Global Exchange (MIRAGE). The treatment of water uptake in MIRAGE agrees with laboratory measurements, and the growth of aerosol extinction with relative humidity in MIRAGE simulations agrees with field measurements. The simulated frequency of relative humidity near 100% is about twice that of analyzed relative humidity. When the analyzed relative humidity is used to calculate aerosol water uptake in MIRAGE, the simulated aerosol optical depth agrees with most surface measurements after cloudy conditions are filtered out and differences between model and station elevations are accounted for, but simulated optical depths are too low over Brazil and central Canada. Simulated optical depths are mostly within a factor of 2 of satellite estimates, but are too high off the east coasts of the United States and China and too low off the coast of West Africa and in the Arabian Sea. The simulated single‐scatter albedo is consistent with surface measurements. MIRAGE correctly simulates a larger Ångström exponent near regions with emissions of submicron particles and aerosol precursor gases, and a smaller exponent near regions with emissions of coarse particles. The simulated sensitivity of radiative forcing to aerosol optical depth is consistent with estimates from measurements. The simulated direct forcing is within the uncertainty of estimates from measurements in the North Atlantic. DA - 2001/3/27/ PY - 2001/3/27/ DO - 10.1029/2000JD900502 VL - 106 IS - D6 SP - 5295-5316 SN - 0747-7309 ER - TY - JOUR TI - A physically based estimate of radiative forcing by anthropogenic sulfate aerosol AU - Ghan, SJ AU - Easter, RC AU - Chapman, EG AU - Abdul-Razzak, H AU - Zhang, Y AU - Leung, LR AU - Laulainen, NS AU - Saylor, RD AU - Zaveri, RA T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Estimates of direct and indirect radiative forcing by anthropogenic sulfate aerosols from an integrated global aerosol and climate modeling system are presented. A detailed global tropospheric chemistry and aerosol model that predicts concentrations of oxidants as well as aerosols and aerosol precursors, is coupled to a general circulation model that predicts both cloud water mass and cloud droplet number. Both number and mass of several externally mixed aerosol size modes are predicted, with internal mixing assumed for the different aerosol components within each mode. Predicted aerosol species include sulfate, organic and black carbon, soil dust, and sea salt. The models use physically based treatments of aerosol radiative properties (including dependence on relative humidity) and aerosol activation as cloud condensation nuclei. Parallel simulations with and without anthropogenic sulfate aerosol are performed for a global domain. The global and annual mean direct and indirect radiative forcing due to anthropogenic sulfate are estimated to be −0.3 to −0.5 and −1.5 to −3.0 W m −2 , respectively. The radiative forcing is sensitive to the model's horizontal resolution, the use of predicted versus analyzed relative humidity, the prediction versus diagnosis of aerosol number and droplet number, and the parameterization of droplet collision/coalescence. About half of the indirect radiative forcing is due to changes in droplet radius and half to increased cloud liquid water. DA - 2001/3/27/ PY - 2001/3/27/ DO - 10.1029/2000JD900503 VL - 106 IS - D6 SP - 5279-5293 SN - 0747-7309 ER - TY - JOUR TI - Selective mortality during the larval-juvenile transition in two coral reef fishes AU - Searcy, S. P. AU - Sponaugle, S. T2 - Ecology (Brooklyn, New York, N.Y.) DA - 2001/// PY - 2001/// VL - 82 IS - 9 SP - 2452-2470 ER - TY - JOUR TI - Wavelet analysis and the governing dynamics of a large-amplitude mesoscale gravity-wave event along the East Coast of the United States AU - Zhang, F. Q. AU - Koch, S. E. AU - Davis, C. A. AU - Kaplan, M. L. T2 - Quarterly Journal of the Royal Meteorological Society AB - Detailed diagnostic analyses are performed upon a mesoscale numerical simulation of a well-observed gravity-wave event that occurred on 4 January 1994 along the East Coast of the United States. The value of using wavelet analysis to investigate the evolving gravity-wave structure and of using potential vorticity (PV) inversion to study the nature of the flow imbalance in the wave generation region is demonstrated. The cross-stream Lagrangian Rossby number, the residual in the nonlinear balance equation, and the unbalanced geopotential-height field obtained from PV inversion are each evaluated for their usefulness in diagnosing the flow imbalance. All of these fields showed clear evidence of strong imbalance associated with a middle-to-upper tropospheric jet streak, and tropopause fold upstream of the large-amplitude gravity wave several hours before the wave became apparent at the surface. Analysis indicates that a train of gravity waves was continuously generated by geostrophic adjustment in the exit region of the unbalanced upper-level jet streak as it approached the inflection axis in the height field immediately downstream of the maximum imbalance associated with the tropopause fold. A split front in the middle troposphere, characterized by the advance of the dry conveyor belt above the warm front, was overtaken by one of these propagating waves. During this merger process, a resonant interaction resulted, which promoted the rapid amplification and scale contraction of both the incipient wave (nonlinear wave development) and the split front (frontogenesis). The gravity wave and front aloft became inseparable following this merger. The situation became even more complex within a few hours as the vertical motion enhanced by this front-wave interaction acted upon a saturated, potentially unstable layer to produce elevated moist convection. An analysis of the temporal changes in the vertical profile of wave energy flux suggests that moist convective downdraughts efficiently transported the wave energy from the midlevels downward beneath the warm-front surface, where the wave became ducted. However, pure ducting was not sufficient for maintaining and amplifying the waves; rather, wave-CISK (Conditional Instability of the Second Kind) was crucial. This complex sequence of nonlinear interactions produced a long-lived, large-amplitude gravity wave that created hazardous winter weather and disrupted society over a broad and highly populated area. Although gravity waves with similar appearance to this large-amplitude wave of depression occasionally have been seen in other strong cyclogenesis cases involving a jet streak ahead of the upper-level trough axis, it is unknown whether other such events share this same sequence of interactions. DA - 2001/// PY - 2001/// DO - 10.1256/smsqj.57701 VL - 127 IS - 577 SP - 2209-2245 ER - TY - JOUR TI - Use of molecular probes to assess geographic distribution of Pfiesteria species AU - Rublee, PA AU - Kempton, JW AU - Schaefer, EF AU - Allen, C AU - Harris, J AU - Oldach, DW AU - Bowers, H AU - Tengs, T AU - Burkholder, JM AU - Glasgow, HB T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454924 VL - 109 SP - 765-767 SN - 0091-6765 KW - molecular probes KW - PCR KW - Pfiesteria KW - toxic dinoflagellates ER - TY - JOUR TI - The standardized fish bioassay procedure for detecting and culturing actively toxic Pfiesteria, used by two reference laboratories for Atlantic and Gulf Coast states AU - Burkholder, JM AU - Marshall, HG AU - Glasgow, HB AU - Seaborn, DW AU - Deamer-Melia, NJ T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454922 VL - 109 SP - 745-756 SN - 1552-9924 KW - culture KW - dinoflagellates KW - functional type KW - standardized fish bioassay KW - toxic Pfiesteria complex ER - TY - JOUR TI - Seasonal evolution of hydrographic properties in the Antarctic circumpolar current at 170 degrees W during 1997-1998 AU - Morrison, JM AU - Gaurin, S AU - Codispoti, LA AU - Takahashi, T AU - Millero, FJ AU - Gardner, WD AU - Richardson, MJ T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - This paper discusses the seasonal evolution of the hydrographic and biogeochemical properties in the Antarctic Circumpolar Current (ACC) during the US Joint Global Ocean Flux (JGOFS) Antarctic Environment and Southern Ocean Process Study (AESOPS) in 1997–1998. The location of the study region south of New Zealand along ∼170°W was selected based on the zonal orientation and meridional separation of the physical and chemical fronts found in that region. Here we endeavor to describe the seasonal changes of the macronutrients, fluorescence chlorophyll, particulate organic carbon (POC), and carbon dioxide (CO2) in the upper 400 m of the ACC during the evolution of the seasonal phytoplankton bloom found in this area. While the ACC has extreme variability in the meridional sense (due to fronts, etc.), it appears to be actually quite uniform in the zonal sense. This is reflected by the fact that a good deal of the seasonal zonal changes in nutrients distributions at 170°W follow a pattern that reflects what would be expected if the changes are associated with seasonal biological productivity. Also at 170°W, the productivity of the upper waters does not appear to be limited by availability of phosphate or nitrate. While there is a significant decrease (or uptake) of inorganic nitrogen, phosphate and silicate associated with the seasonal phytoplankton bloom, none of the nutrients, except perhaps silicate (north of the silicate front) are actually depleted within the euphotic zone. At the end of the growing season, nutrient concentrations rapidly approached their pre-bloom levels. Inspection of the ratios of apparent nutrient drawdown near 64°S suggests N/P apparent drawdowns to have a ratio of ∼10 and N/Si apparent drawdowns to have a ratio of >4. These ratios suggest a bloom that was dominated by Fe limited diatoms. In addition, the surface water in the Polar Front (PF) and the Antarctic Zone (AZ) just to the south of the PF take up atmospheric CO2 at a rate 2–3 times as fast as the mean global ocean rate during the summer season but nearly zero during the rest of year. This represents an important process for the transport of atmospheric CO2 into the deep ocean interior. Finally, the net CO2 utilization or the net community production during the 2.5 growing months between the initiation of phytoplankton blooms and mid-January increase southward from 1.5 mol C m−2 at 55°S to 2.2 mol C m−2 to 65°S across the Polar Frontal Zone (PFZ) into the AZ. DA - 2001/// PY - 2001/// DO - 10.1016/S0967-0645(01)00075-3 VL - 48 IS - 19-20 SP - 3943-3972 SN - 1879-0100 ER - TY - JOUR TI - Microfluorimetric analysis of a purinergic receptor (P2X(7)) in GH(4)C(1) rat pituitary cells: Effects of a bioactive substance produced by Pfiesteria piscicida AU - Melo, AC AU - Moeller, PDR AU - Glasgow, H AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454920 VL - 109 SP - 731-737 SN - 0091-6765 KW - GH(4)C(1) KW - Pfiesteria KW - purinergic receptors KW - P2X(7) KW - toxin ER - TY - JOUR TI - Field ecology of toxic Pfiesteria complex species and a conservative analysis of their role in estuarine fish kills AU - Glasgow, HB AU - Burkholder, JM AU - Mallin, MA AU - Deamer-Melia, NJ AU - Reed, RE T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454919 VL - 109 SP - 715-730 SN - 1552-9924 KW - dinoflagellates KW - dissolved oxygen KW - estuaries KW - fish kills KW - nutrients KW - toxic Pfiesteria complex ER - TY - JOUR TI - Current progress in isolation and characterization of toxins isolated from Pfiesteria piscicida AU - Moeller, PDR AU - Morton, SL AU - Mitchell, BA AU - Sivertsen, SK AU - Fairey, ER AU - Mikulski, TM AU - Glasgow, H AU - Deamer-Melia, NJ AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454921 VL - 109 SP - 739-743 SN - 0091-6765 KW - assay KW - chromatography KW - GH(4)C(1) KW - Pfiesteria piscicida KW - toxin bioassay ER - TY - JOUR TI - Marine reserves for Caribbean spiny lobster: empirical evaluation and theoretical metapopulation recruitment dynamics AU - Lipcius, RN AU - Stockhausen, WT AU - Eggleston, DB T2 - MARINE AND FRESHWATER RESEARCH AB - Field data on spiny-lobster abundance, habitat quality, and hydrodynamic transport patterns for a reserve (ECLSP) and three exploited sites (CI, EI, LSI) were used to assess reserve success in reducing fishing mortality and increasing theoretical metapopulation recruitment. Fishing mortality was estimated empirically by quantification of lobster density at ECLSP and the three exploited sites before and after the start of the fishing season in two years. Fishing mortality was estimated to be 47–98% lower at the reserve. Using a circulation model , we theoretically assessed effectiveness of ECLSP and nominal reserves at the exploited sites in augmenting recruitment through redistribution of larvae to all sites. Larvae discharged from ECLSP and EI recruited throughout Exuma Sound, whereas those from LSI and CI recruited only to CI and LSI. Hence, only reserves at EI and ECLSP would be suitable for metapopulation recruitment. In selecting an optimal reserve for metapopulation recruitment, use of information on habitat quality or adult density did not yield a higher probability of success than did determining the reserve location by chance. The only successful strategy was one that used information on transport processes. Designation of effective marine reserves therefore requires careful attention to metapopulation dynamics and recruitment processes. DA - 2001/// PY - 2001/// DO - 10.1071/MF01193 VL - 52 IS - 8 SP - 1589-1598 SN - 1448-6059 KW - marine protected areas KW - Panulirus argus KW - metapopulation dynamics KW - source-sink dynamics KW - larval transport KW - larval supply KW - marine conservation biology KW - no-take reserves ER - TY - JOUR TI - Use of Monte Carlo uncertainty analyses to evaluate differences in observed and predicted ozone concentrations AU - Hanna, , SR AU - Davis, JM T2 - INTERNATIONAL JOURNAL OF ENVIRONMENT AND POLLUTION AB - It is now possible to carry out Monte Carlo uncertainty studies with large photochemical grid models such as UAM-IV. The current study uses information on the effects of uncertainties in 109 input variables on UAM-IV model predictions of maximum daily one-hour averaged ozone concentrations at 29 monitoring sites in the New York City UAM domain for the 8 July 1988 ozone episode. Fifty Monte Carlo runs were made with the UAM-IV model making use of simple random sampling from assumed distributions for each input variable. The resulting sets of 50 predicted values of ozone concentration allowed Cumulative Distribution Functions (CDFs) to be determined for each site. These CDFs were typically log-normal with a standard deviation of about -10% or -20%. Note that these uncertainties are due only to uncertainties in input variables and do not include contributions due to errors in model physics or stochastic fluctuations. The Lewellen-Sykes-Parker (LSP) model evaluation methodology has been applied to the predictions of maximum daily one-hour averaged ozone concentrations at the 29 monitoring sites using the CDFs from the Monte Carlo study. The assumption is tested that the model prediction is correct, in the sense that the observations are not significantly different from the predictions. The hypothesis is tested that the Monte Carlo CDFs of predicted concentrations represent a set of 50 realisations from the population of observed concentrations. Therefore the Monte Carlo results were used to generate many possible realisations of CDFs of model residuals, i.e. observed minus predicted concentration, which were then compared with the actual CDF of model residuals at the 29 sites. It was found, as expected, that the single actual CDF line for the model residuals covered a slightly broader range (a standard deviation of about 20% compared to about 10%) than the 95% confidence intervals for the CDFs from the 50 Monte Carlo runs. DA - 2001/// PY - 2001/// DO - 10.1504/IJEP.2001.000608 VL - 16 IS - 1-6 SP - 80-87 SN - 0957-4352 KW - model evaluation KW - Monte Carlo uncertainties KW - ozone predictions KW - photochemical grid model ER - TY - JOUR TI - Distribution and abundance of Caribbean spiny lobsters in the Key West National Wildlife Refuge: relationship to habitat features and impact of an intensive recreational fishery AU - Eggleston, DB AU - Dahlgren, CP T2 - MARINE AND FRESHWATER RESEARCH AB - During 1999 we determined abundance and size frequency of the Caribbean spiny lobster, Panulirus argus, in various habitats within the ‘Lakes’ and ‘Marquesas’ regions (122 km2 ) of the Key West National Wildlife Refuge (KWNWR), USA, using visual surveys. We also assessed the relationship between lobster abundance and habitat characteristics. During July–August 2000, we quantified the impact of a two-day recreational fishing ‘miniseason’ in fished and nonfished areas within the KWNWR. Lobster density was highest in channels, followed by hard bottom and patch reefs. P. argus was rarely observed in sea-grass and never in mangrove prop-roots. Its density was related to density and volume of large sponges in channel habitats. Although channels represent only 0.06% of the study area, they provide abundant refuges and a likely corridor for migrating juveniles. The two-day fishing season reduced density of lobsters >7 cm CL by an average of 80% across several habitats, including three marine protected areas closed to fishing. The observed decline was probably due to fishing, because percent change in density was related to number of recreational boats anchored at a given site. Relatively small marine protected areas (30–150 ha) may therefore be too small to protect the population structure of P. argus adequately within the KWNWR. DA - 2001/// PY - 2001/// DO - 10.1071/MF01203 VL - 52 IS - 8 SP - 1567-1576 SN - 1448-6059 ER - TY - JOUR TI - Introduction to the symposium: Ontogenetic strategies of invertebrates in aquatic environments AU - Charmantier, G AU - Wolcott, DL T2 - AMERICAN ZOOLOGIST AB - This symposium presents different ecological and physiological strategies used by invertebrates to successfully adapt to aquatic environments. Adaptation has been studied mainly in adult animals, but the papers comprising the symposium emphasize ontogenetic strategies, starting from the principle that natural selection acts on all stages of development. Adaptive strategies may thus differ strikingly between developmental stages of the same organism. Invertebrates offer a wide array of ecophysiological models for study, and these are exemplified by the contributions to the symposium, which are briefly summarized. Future research in the field will 1, expand the number of models for comparative purposes; 2, examine the strategies, not only of larvae and juveniles, but also of embryos, eggs and reproductive cells; and 3, investigate the genetic basis of ontogenetic strategies. DA - 2001/11// PY - 2001/11// DO - 10.1668/0003-1569(2001)041[1053:ITTSOS]2.0.CO;2 VL - 41 IS - 5 SP - 1053-1056 SN - 0003-1569 ER - TY - JOUR TI - Temporal trends of black carbon concentrations and regional climate forcing in the southeastern United States AU - Im, JS AU - Saxena, VK AU - Wenny, BN T2 - ATMOSPHERIC ENVIRONMENT AB - The effect of black carbon (BC) on climate forcing is potentially important, but its estimates have large uncertainties due to a lack of sufficient observational data. The BC mass concentration in the southeastern US was measured at a regionally representative site, Mount Gibbes (35.78°N, 82.29°W, 2006 m MSL). The air mass origin was determined using 48-h back trajectories obtained from the hybrid single-particle Lagrangian integrated trajectory model. The highest average concentration is seen in polluted continental air masses and the lowest in marine air masses. During the winter, the overall average BC value was 74.1 ng m−3, whereas the overall summer mean BC value is higher by a factor of 3. The main reason for the seasonal difference may be enhanced thermal convection during summer, which increases transport of air pollutants from the planetary boundary layer of the surrounding urban area to this rural site. In the spring of 1998, abnormally high BC concentrations from the continental sector were measured. These concentrations were originating from a biomass burning plume in Mexico. This was confirmed by the observations of the Earth probe total ozone mapping spectrometer. The BC average concentrations of air masses transported from the polluted continental sector during summer are low on Sunday to Tuesday with a minimum value of 256 ng m−3 occurring on Monday, and high on Wednesday to Friday with a maximum value of 379 ng m−3 occurring on Friday. The net aerosol radiative forcing (scattering effects plus absorption effects) per unit vertical depth at 2006 m MSL is calculated to be −1.38×10−3 W m−3 for the southeastern US. The magnitude of direct radiative forcing by aerosol scattering is reduced by 15±7% due to the BC absorption. DA - 2001/7// PY - 2001/7// DO - 10.1016/S1352-2310(00)00520-3 VL - 35 IS - 19 SP - 3293-3302 SN - 1352-2310 KW - aerosol KW - black carbon KW - absorption KW - direct radiative climate forcing KW - temporal patterns ER - TY - JOUR TI - Specificity of cognitive impairment from Pfiesteria piscicida exposure in rats - Attention and visual function versus behavioral plasticity AU - Rezvani, AH AU - Bushnell, PJ AU - Burkholder, JM AU - Glasgow, HB AU - Levin, ED T2 - NEUROTOXICOLOGY AND TERATOLOGY AB - Pfiesteria piscicida is a toxic dinoflagellate that has caused massive fish kills in estuaries along the East Coast of the United States, and exposure of humans to toxic Pfiesteria has been associated with cognitive impairment. A visual signal detection task was used to determine the possible importance of attentional and visual processes in Pfiesteria effects on cognitive function. Adult female rats were trained to perform the signal detection task. After training, the rats were injected subcutaneously with fish culture water containing toxic Pfiesteria (35,600 or 106,800 cells of Pfiesteria/kg of rat body weight) or with (control) fish culture water containing no Pfiesteria. Effects of toxic Pfiesteria on maintenance of signal detection behavior were assessed for 2 weeks after treatment. Then, the signal-response contingencies were reversed. After the discrimination was reestablished on the reversed levers, the rats received a second dose of toxic Pfiesteria. The rats were again tested for 2 weeks, after which a second reversal was imposed. Pfiesteria did not affect behavior in the signal detection task during 2 weeks of prereversal testing after either exposure. However, a significant Pfiesteria-induced deficit emerged when the signal-response contingencies were reversed. These findings suggest that Pfiesteria-induced deficits emerge during periods of behavioral transition and not during performance of previously learned tasks. DA - 2001/// PY - 2001/// DO - 10.1016/S0892-0362(01)00169-6 VL - 23 IS - 6 SP - 609-616 SN - 1872-9738 KW - toxic KW - dinoflagellates KW - Pfiesteria KW - learning KW - visual signal detection test KW - radial-ann maze KW - figure-8 maze ER - TY - JOUR TI - Simulation of boundary layer structure over the Indian summer monsoon trough during the passage of a depression AU - Potty, KVJ AU - Mohanty, UC AU - Raman, S T2 - JOURNAL OF APPLIED METEOROLOGY AB - The planetary boundary layer (PBL) structure over the Indian summer monsoon trough region has been simulated using a regional numerical model during the passage of a monsoon depression along the monsoon trough. Monin–Obukhov similarity theory for the surface layer coupled with turbulent kinetic energy closure scheme (1½-order closure) for the mixed layer is used for parameterizing the PBL in the model. The results show that the model is able to simulate the evolution and the structure of the monsoon trough boundary layer and its associated features. The main observed characteristic features of the monsoon trough, such as the southward tilt of the trough with height and warmer air mass toward the northern side of the trough line, are simulated well by the model. Numerical results also indicate that the dynamic and thermodynamic characteristics of the monsoon trough boundary layer are modified by the passage of monsoon depressions. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0450(2001)040<1241:SOBLSO>2.0.CO;2 VL - 40 IS - 7 SP - 1241-1254 SN - 0894-8763 ER - TY - JOUR TI - Persistent solar influence on north Atlantic climate during the Holocene AU - Bond, G AU - Kromer, B AU - Beer, J AU - Muscheler, R AU - Evans, MN AU - Showers, W AU - Hoffmann, S AU - Lotti-Bond, R AU - Hajdas, I AU - Bonani, G T2 - SCIENCE AB - Surface winds and surface ocean hydrography in the subpolar North Atlantic appear to have been influenced by variations in solar output through the entire Holocene. The evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon-14 and beryllium-10 and centennial to millennial time scale changes in proxies of drift ice measured in deep-sea sediment cores. A solar forcing mechanism therefore may underlie at least the Holocene segment of the North Atlantic's "1500-year" cycle. The surface hydrographic changes may have affected production of North Atlantic Deep Water, potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally. DA - 2001/12/7/ PY - 2001/12/7/ DO - 10.1126/science.1065680 VL - 294 IS - 5549 SP - 2130-2136 SN - 1095-9203 ER - TY - JOUR TI - Numerical study of the intertropical convergence zone over the Indian Ocean during the 1997 and 1998 northeast monsoon episodes AU - Roswintiarti, O AU - Raman, S AU - Mohanty, UC T2 - PURE AND APPLIED GEOPHYSICS DA - 2001/6// PY - 2001/6// DO - 10.1007/PL00001217 VL - 158 IS - 5-6 SP - 989-1015 SN - 0033-4553 KW - ITCZ KW - Indian Ocean KW - northeast monsoon KW - El Nino KW - NRL/NCSU model ER - TY - JOUR TI - Measurements and analysis of criteria pollutants in New Delhi, India AU - Aneja, VP AU - Agarwal, A AU - Roelle, PA AU - Phillips, SB AU - Tong, QS AU - Watkins, N AU - Yablonsky, R T2 - ENVIRONMENT INTERNATIONAL AB - Ambient concentrations of carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and total suspended particulates (TSP) were measured from January 1997 to November 1998 in the center of downtown [the Income Tax Office (ITO) located on B.S.G. Marg] New Delhi, India. The data consist of 24-h averages of SO2, NOx, and TSP as well as 8 and 24-h averages of CO. The measurements were made in an effort to characterize air pollution in the urban environment of New Delhi and assist in the development of an air quality index. The yearly average CO, NOx, SO2, and TSP concentrations for 1997 and 1998 were found to be 4810±2287 and 5772±2116 μg/m3, 83±35 and 64±22 μg/m3, 20±8 and 23±7 μg/m3, and 409±110 and 365±100 μg/m3, respectively. In general, the maximum CO, SO2, NOx, and TSP values occurred during the winter with minimum values occurring during the summer, which can be attributed to a combination of meteorological conditions and photochemical activity in the region. The ratio of CO/NOx (∼50) indicates that mobile sources are the predominant contributors for these two compounds in the urban air pollution problem in New Delhi. The ratio of SO2/NOx (∼0.6) indicates that point sources are contributing to SO2 pollution in the city. The averaged background CO concentrations in New Delhi were also calculated (∼1939 μg/m3) which exceed those for Eastern USA (∼500 μg/m3). Further, all measured concentrations exceeded the US National Ambient Air Quality Standards (NAAQS) except for SO2. TSP was identified as exceeding the standard on the most frequent basis. DA - 2001/7// PY - 2001/7// DO - 10.1016/S0160-4120(01)00051-4 VL - 27 IS - 1 SP - 35-42 SN - 0160-4120 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0034923291&partnerID=MN8TOARS KW - criteria pollutants KW - USNAAQS KW - nitrogen oxides KW - sulfur dioxides KW - total suspended particulates KW - carbon monoxide KW - India air quality ER - TY - BOOK TI - Introduction to micrometeorology (2nd ed.) AU - Arya, S. P. S CN - QC883.8 .A79 2001 DA - 2001/// PY - 2001/// PB - San Diego, CA: Academic Press SN - 0120593548 ER - TY - JOUR TI - Discrete particle model for sheet flow sediment transport in the nearshore AU - Drake, TG AU - Calantoni, J T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - Fully three‐dimensional discrete particle computer simulations of high‐concentration sheet flow transport in oscillatory flows quantify the effect of fluid acceleration on bed load transport in highly unsteady flows typical of nearshore marine environments. A simple impulse‐momentum approach explains simulation results and forms the basis for adding an acceleration‐related term to widely used energetics sediment transport formulae. Transport predicted by the acceleration term becomes increasingly significant as wave shape approaches the sawtooth profile characteristic of surf zone bores. Simulations integrate F = ma and a corresponding set of equations for the torques for each sphere. Normal and tangential forces between contacting particles are linear functions of the distance between sphere centers and the relative tangential displacement at the contact point, respectively; particle interactions are both inelastic and frictional. Pressure gradient forces generated by the passage of surface gravity waves drive fluid and particle motion in a stack of thin horizontal fluid layers that exchange momentum and exert fluid drag, added mass, and buoyancy forces on particles. Transport properties of the simulated granular‐fluid assemblage are robust to large variations in material properties of the particles. Simulated transport rates agree with available experimental data for unsteady transport of coarse sands; the mode of bed load motion, dispersion of bed load particles, and particle segregation by size and density are qualitatively consistent with available particle‐scale observations of bed load transport of natural particles. DA - 2001/9/15/ PY - 2001/9/15/ DO - 10.1029/2000JC000611 VL - 106 IS - C9 SP - 19859-19868 SN - 2169-9291 ER - TY - JOUR TI - Chemosensory attraction of zoospores of the estuarine dinoflagellates, Pfiesteria piscicida and P-shumwayae, to finfish mucus and excreta AU - Cancellieri, PJ AU - Burkholder, JM AU - Deamer-Melia, NJ AU - Glasgow, HB T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Toxic strains of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, can cause fish death and disease, whereas other estuarine ‘lookalike’ species such as cryptoperidiniopsoids have not been ichthyotoxic under ecologically relevant conditions. Chemosensory attraction of three functional types of these Pfiesteria spp. were separately evaluated for their attraction to fresh fish mucus and excreta. Clonal cultures of actively toxic (TOX-A, engaged in killing fish) and temporarily nontoxic (tested as toxic but without access to live fish for >1 week to 5 months (in most experiments, ≤3 months) as ‘short-duration’ TOX-B; and without access to live fish for ≥1.5 years as ‘long-duration’ TOX-B) functional types of P. piscicida and P. shumwayae were derived from the same clones whereas the non-inducible cultures (NON-IND, tested as incapable of toxic activity in the presence of fish), of necessity, were from different clonal isolates. NON-IND cultures previously had been grown on algal prey for 3–8 months, and had repeatedly been tested as incapable of causing fish distress, disease or death via toxic activity. Attraction to fish materials was based on the number of zoospores that entered microcapillary tubes containing sterile-filtered 15-ppt water (controls), vs. entry into tubes with sterile-filtered mucus and excreta (collected in 15-ppt water) that had been collected from live tilapia, bluegill, hybrid striped bass, and Atlantic menhaden (tested separately within 3 h of removal from live fish). TOX-A zoospores of both Pfiesteria species exhibited the strongest attraction to the fish mucus and excreta, with comparable response to the materials from all four test fish species. Short-duration TOX-B zoospores showed an intermediate response that apparently depended on the duration of mucus separation from the live fish: the shorter the separation period, the stronger the zoospore attraction to the fish materials. In contrast to TOX-A and short-duration TOX-B zoospores, NON-IND and long-duration TOX-B zoospores generally showed little or no response to the fish materials. Zoospores of the cryptoperidiniopsoid demonstrated a moderate attraction that did not appear to depend on the time of isolation from fish. TOX-A zoospores were also tested for attraction to sterile-filtered vs. non-filtered fish mucus (time separated from the live animal, 3–96 h). These zoospores, which initially had been actively attracted, were no longer attracted to the unfiltered fish materials after 48 h, whereas attraction to the sterile-filtered fish mucus and excreta persisted throughout the duration of the experiment. Thus, the attractant signal in the materials was degraded or effectively blocked by the bacterial community within hours of isolation from live fish. This study indicates the importance of functional type or toxicity status, and the importance of the history of exposure to live fish, in the behavioral ecology of Pfiesteria spp. Initial attraction to fish materials strongly depended on the functional type, and on the history of toxic activity. Non-inducible and long-duration TOX-B cultures of Pfiesteria spp., unlike actively toxic and short-duration TOX-B (potentially toxic) strains, initially were virtually unresponsive to fish mucus. DA - 2001/9/15/ PY - 2001/9/15/ DO - 10.1016/S0022-0981(01)00299-4 VL - 264 IS - 1 SP - 29-45 SN - 1879-1697 KW - chemosensory KW - functional type KW - estuary KW - fish mucus KW - non-inducible KW - toxic dinoflagellate KW - toxic Pfiesteria complex KW - cryptoperidiniopsoid ER - TY - JOUR TI - Tracing nitrate transport and environmental impact from intensive swine farming using delta nitrogen-15 AU - Karr, JD AU - Showers, WJ AU - Gilliam, JW AU - Andres, AS T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - Natural-abundance delta15N showed that nitrate generated from commercial land application of swine (Sus scrofa domesticus) waste within a North Carolina Coastal Plain catchment was being discharged to surface waters by ground water passing beneath the sprayfields and adjacent riparian buffers. This was significant because intensive swine farms in North Carolina are considered non-discharge operations, and riparian buffers with minimum widths of 7.6 m (25 ft) are the primary regulatory control on ground water export of nitrate from these operations. This study shows that such buffers are not always adequate to prevent discharge of concentrated nitrate in ground water from commercial swine farms in the Mid-Atlantic Coastal Plain, and that additional measures are required to ensure non-discharge conditions. The median delta15N-total N of liquids in site swine waste lagoons was +15.4 +/- 0.2% vs. atmospheric nitrogen. The median delta15N-NO3 values of shallow ground water beneath and adjacent to site sprayfields, a stream draining sprayfields, and waters up to 1.5 km downstream were + 15.3 +/- 0.2 to + 15.4 +/- 0.2%. Seasonal and spatial isotopic variations in lagoons and well waters were greatly homogenized during ground water transport and discharge to streams. Neither denitrification nor losses of ammonia during spraying significantly altered the bulk ground water delta15N signal being delivered to streams. The lagoons were sources of chloride and potassium enrichment, and shallow ground water showed strong correlation between nitrate N, potassium, and chloride. The 15N-enriched nitrate in ground water beneath swine waste sprayfields can thus be successfully traced during transport and discharge into nearby surface waters. DA - 2001/// PY - 2001/// DO - 10.2134/jeq2001.3041163x VL - 30 IS - 4 SP - 1163-1175 SN - 1537-2537 ER - TY - JOUR TI - Oxygen isotope variability in bones of wild caught and constant temperature reared sub-adult American alligators AU - Stoskopf, MK AU - Barrick, RE AU - Showers, WJ T2 - JOURNAL OF THERMAL BIOLOGY AB - (1) The mean delta18O(BP) ( per thousandSMOW) for any given bone sampled from captive alligators maintained at high constant temperature was lower (indicative of higher temperatures of bone deposition) than that of the same bone from wild alligators caught in Northern Florida, but these differences were only greater than two standard deviations from the mean for the thoracic vertebrae and metatarsal bones. (2) Inter-bone variability of delta18O(BP) ( per thousandSMOW) was similar for captive alligators maintained at constant temperatures and the wild alligators, but intra-bone variability was much greater in wild alligators. (3) The order of mean delta18O(BP) ( per thousandSMOW) of bones (from highest to lowest) differed between treatment groups. However, intra-bone variability obscured the significance of those differences. Nevertheless, the thoracic vertebra had the highest mean delta18O(BP) ( per thousandSMOW), indicative of lower temperatures, and the lowest variability of bones in both groups of alligators. Conversely, the tibia was one of the warmest and more variable bones in both groups of alligators. (4) The pattern of delta18O(BP) ( per thousandSMOW) values across sites within long bones were identical between alligator treatment groups for the femur and humerus but differed between groups for the tibia and metatarsus, and differed between different long bones. The predicted intra-bone pattern for long bones of increasing delta18O(BP) ( per thousandSMOW) indicative of lower temperatures in more distal sampling sites was only obtained from the femurs. (5) Paired cortical and cancellous bone samples from the same site from all individuals in both treatment groups were available for proximal humeri and distal femurs. delta18O(BP) ( per thousandSMOW) values from cortical bone were more variable than those from cancellous bone for both bones. (6) Cortical bone had lower delta18O(BP) ( per thousandSMOW) values indicative of warmer temperatures than cancellous bone at sites sampled on the proximal humeri and distal femurs of all three animals from both treatment groups. DA - 2001/6// PY - 2001/6// DO - 10.1016/S0306-4565(00)00041-3 VL - 26 IS - 3 SP - 183-191 SN - 0306-4565 KW - bone KW - heterothermy KW - oxygen isotopes KW - alligator KW - reptile KW - thermoregulation ER - TY - JOUR TI - Numerical study of the role of land-air-sea interactions for the northeasterly monsoon circulations over Indian Ocean during INDOEX AU - Mohanty, U. C. AU - Niyogi, D. S. AU - Raman, S. AU - Sarkar, A. T2 - Current Science DA - 2001/// PY - 2001/// VL - 80 IS - 2001 Apr. 10 SP - 60-68 ER - TY - JOUR TI - Numerical simulations of a gravity wave event over CCOPE. Part III: The role of a mountain-plains solenoid in the generation of the second wave episode AU - Koch, SE AU - Zhang, FQ AU - Kaplan, ML AU - Lin, YL AU - Weglarz, R AU - Trexler, CM T2 - MONTHLY WEATHER REVIEW AB - Mesoscale model simulations have been performed of the second episode of gravity waves observed in great detail in previous studies on 11–12 July 1981 during the Cooperative Convective Precipitation Experiment. The dominant wave simulated by the model was mechanically forced by the strong updraft associated with a mountain–plains solenoid (MPS). As this updraft impinged upon a stratified shear layer above the deep, well-mixed boundary layer that developed due to strong sensible heating over the Absaroka Mountains, the gravity wave was created. This wave rapidly weakened as it propagated eastward. However, explosive convection developed directly over the remnant gravity wave as an eastward-propagating density current produced by a rainband generated within the MPS leeside convergence zone merged with a westward-propagating density current in eastern Montana. The greatly strengthened cool pool resulting from this new convection then generated a bore wave that appeared to be continuous with the movement of the incipient gravity wave as it propagated across Montana and the Dakotas. The nonlinear balance equation and Rossby number were computed to explore the role of geostrophic adjustment in the forecast gravity wave generation, as suggested in previous studies of this wave event. These fields did indicate flow imbalance, but this was merely the manifestation of the MPS-forced gravity wave. Thus, the imbalance indicator fields provided no lead time for predicting wave occurrence. Several sensitivity tests were performed to study the role of diabatic processes and topography in the initiation of the flow imbalance and the propagating gravity waves. When diabatic effects owing to precipitation were prevented, a strong gravity wave still was generated in the upper troposphere within the region of imbalance over the mountains. However, it did not have a significant impact because moist convection was necessary to maintain wave energy in the absence of an efficient wave duct. No gravity waves were present in either a simulation that disallowed surface sensible heating, or the “flat terrain” simulation, because the requisite MPS forcing could not occur. This study highlights difficulties encountered in attempting to model the generation of observed gravity waves over complex terrain in the presence of strong diabatic effects. The complex interactions that occurred between the sensible heating over complex terrain, the incipient gravity wave, and convection highlight the need for much more detailed observations between wave generation regions over mountains and the plains downstream of such regions. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0493(2001)129<0909:NSOAGW>2.0.CO;2 VL - 129 IS - 5 SP - 909-933 SN - 0027-0644 ER - TY - JOUR TI - Influence of environmental nutrient conditions on Gymnodinium breve (Dinophyceae) population dynamics: a numerical study AU - Liu, G AU - Janowitz, GS AU - Kamykowski, D 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 213:13-37 (2001) - doi:10.3354/meps213013 Influence of environmental nutrient conditions on Gymnodinium breve (Dinophyceae) population dynamics: a numerical study Gang Liu, Gerald S. Janowitz*, Daniel Kamykowski Department of Marine, Earth & Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA *Corresponding author. E-mail: janowitz@ncsu.edu ABSTRACT: A model of Gymnodinium breve population dynamics modified from Liu et al. (2001; Mar Ecol Prog Ser 210:101-124) is used to investigate the influence of various nutrient conditions on the population increase of an alongshore population filament of G. breve cells as it moves onshore across a continental shelf. The environmental conditions in the model are derived from measurements or theory applicable to bloom development on the west Florida shelf. The simulations indicate that the potential nutrient input patterns here represented by nitrogen sources on the shelf, i.e., offshore, mid-shelf and coastal upwellings, a Trichodesmium-released surface nitrogen source associated with multi-nutrient ocean fertilization by air-borne dust input, and a coastal surface plume are all eligible to trigger and/or support a G. breve bloom. However, the occurrence, timing, location, duration, and intensity of the bloom are determined by nitrogen concentration, input location, and temporal availability. Some nitrogen support at the offshore initiation stage of population growth may induce earlier bloom development, but without additional nitrogen input in coastal regions, the bloom may not fully develop. As long as the nitrogen is available continuously from offshore through coastal regions, a G. breve population can develop into a fish-killing intensity (1 to 2.5 x 105 cells l-1) in a month or so from a background concentration of <1000 cells l-1 with a maximum growth rate of ~0.16 doublings d-1. An explosive growth stage is not present for the total population in the simulations in which fish-killing cell concentrations are developed in 30 d. However the illusion of explosive growth may be created by the first appearance of a high G. breve population density at the surface late in bloom development. In some cases, daily averaged surface concentration can increase by a factor of 10 in 2 d and increase from a background level of 500 cells l-1 to bloom levels of 104 cells l-1 in 8 d due primarily to surface accumulation resulting from appropriately directed swimming behavior. This numerical investigation further demonstrates that the vertical migration of G. breve can play a critical role not only in the efficient utilization of natural resources, but also in the population distribution. KEY WORDS: Model · Dinoflagellate · Gymnodinium breve · Population dynamics · Behavior · Nutrients Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 213. Online publication date: April 04, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research. DA - 2001/// PY - 2001/// DO - 10.3354/meps213013 VL - 213 SP - 13-37 SN - 1616-1599 KW - model KW - dinoflagellate KW - Gymnodinium breve KW - population dynamics KW - behavior KW - nutrients ER - TY - JOUR TI - Extraction of geopotential height and temperature structure from profiler and rawinsonde winds AU - Businger, S AU - Adams, ME AU - Koch, SE AU - Kaplan, ML T2 - MONTHLY WEATHER REVIEW AB - Mesoscale height and temperature fields can be extracted from the observed wind field by making use of the full divergence equation. Mass changes associated with irrotational ageostrophic motions are retained for a nearly complete description of the height field. Above the boundary layer, in the absence of friction, the divergence equation includes terms composed of the components of the wind and a Laplacian of the geopotential height field. Once the mass field is determined, the thermal structure is obtained through application of the hypsometric equation. In this paper an error analysis of this divergence method is undertaken to estimate the potential magnitude of errors associated with random errors in the wind data. Previous applications of the divergence method have been refined in the following ways. (i) The domain over which the method is applied is expanded to encompass the entire STORM-FEST domain. (ii) Wind data from 23 profiler and 38 rawinsonde sites are combined in the analysis. (iii) Observed profiler and rawinsonde data are interpolated to grid points through a modified objective analysis, and (iv) the variation in elevation of the profiler sites is taken into account. The results of the application of the divergence method to the combined wind data from profiler and rawinsonde sites show good agreement between the retrieved heights and temperatures and the observed values at rawinsonde sites. Standard deviations of the difference between the retrieved and observed data lie well within the precision of the rawinsonde instruments. The difference field shows features whose magnitude is significantly larger than the errors predicted by the error analysis, and these features are systematic rather than random in nature, suggesting that the retrieved fields are able to resolve mesoscale signatures not fully captured by the rawinsonde data alone. The divergence method is also applied solely to the profiler data to demonstrate the potential of the divergence method to provide mass and thermal fields on a routine basis at synoptic times when operational rawinsonde data are not available. A comparison of the heights derived from the profiler winds with those independently measured by rawinsondes indicates that valuable information on the evolution of atmospheric height and temperature fields can be retrieved between conventional rawinsonde release times through application of the divergence method. The implications of the results for applications of the method in weather analysis and in numerical weather prediction are discussed. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0493(2001)129<1729:EOGHAT>2.0.CO;2 VL - 129 IS - 7 SP - 1729-1739 SN - 0027-0644 ER - TY - JOUR TI - Evaluation of sandbar shiner as a surrogate for assessing health risks to the endangered Cape Fear shiner AU - Chittick, B AU - Stoskopf, M AU - Heil, N AU - Levine, J AU - Law, M T2 - JOURNAL OF AQUATIC ANIMAL HEALTH AB - The health status of the endangered Cape Fear shiner Notropis mekistocholas and the suitability of using the sympatric sandbar shiner N. scepticus as an investigative surrogate were evaluated. Forty Cape Fear shiners from three sites and 50 sandbar shiners from five sites were examined. Findings on gill biopsies, fin biopsies, and skin scrapings were limited to low levels of parasitism and gill aneurysms. Eighty-three bacterial isolates representing 13 aerobic species were cultured from the gastrointestinal tracts. A picornavirus was isolated from one pooled sample of sandbar shiners at one site. Forty-three percent of shiners (12 Cape Fear shiners, 27 sandbar shiners) had granulomas in various tissues of the body, 26% (6 Cape Fear, 17 sandbar) had encysted trematodes, 16% (2 Cape Fear, 12 sandbar) had protozoal aggregates in muscle or connective tissue, and 26% (22 Cape Fear shiners, 1 sandbar shiner) had mild, moderate, or moderately severe hepatic vacuolization. Other microscopic lesions included mild parasitism and degrees of inflammation in various tissues. Sandbar shiners appeared to be suitable surrogates for the Cape Fear shiner in bacteriological sampling; however, parasitic, viral, and nonhepatic histological lesions were more common in sandbar shiners. Findings from this study warrant further investigation of sandbar shiners as a conservative bioindicator species for the presence of potential health risks to Cape Fear shiners. DA - 2001/6// PY - 2001/6// DO - 10.1577/1548-8667(2001)013<0086:EOSSAA>2.0.CO;2 VL - 13 IS - 2 SP - 86-95 SN - 1548-8667 ER - TY - JOUR TI - Application of three-dimensional triple nested mesoscale model for assessing the transport and boundary layer variability over the Indian Ocean during INDOEX AU - Roswintiarti, O. AU - Raman, S. AU - Mohanty, U. C. AU - Niyogi, D. S. T2 - Current Science DA - 2001/// PY - 2001/// VL - 80 IS - 2001 Apr. 10 SP - 69-76 ER - TY - JOUR TI - A study on marine boundary layer processes in the ITCZ and non-ITCZ regimes over Indian Ocean with INDOEX IFP-99 data AU - Satyanarayana, A. N. V. AU - Mohanty, U. C. AU - Niyogi, D. S. AU - Raman, S. AU - Lykossov, V. N. AU - Warrior, H. AU - Sam, N. V. T2 - Current Science DA - 2001/// PY - 2001/// VL - 80 IS - 2001 Apr. 10 SP - 39-45 ER - TY - JOUR TI - Real-time detection of split fronts using mesoscale models and WSR-88D radar products AU - Koch, SE T2 - WEATHER AND FORECASTING AB - A structured methodology for detecting the presence of split cold fronts in an operational forecast environment is developed and applied to a case in which a split front passed over a region of cold air damming in the southeastern United States. A real-time mesoscale model and various products from the WSR-88D—including the velocity–azimuth display wind profile (VWP) and hodograph products, plus a thermal advection retrieval scheme applied to the VWP data—are used to study this split front and an associated convective rainband that occurred on 19 December 1995. Wet-bulb temperature and vertical motion forecasts at 700 hPa from the model revealed the arc-shaped split front 300–500 km ahead of the surface cold front. As this midtropospheric front passed across the surface warm front and entered the cold air damming region, model vertical cross-section analyses showed that it created a deep elevated layer of potential instability. Furthermore, an ageostrophic transverse circulation associated with the split front provided the lifting mechanism for releasing this instability as deep convection. Analysis of the absolute geostrophic momentum field provided greater understanding of the structure of the split front and a deep tropospheric frontal system to its west that connected with the surface cold front. An “S–inverted S” pattern in the zero isodop on WSR-88D radial velocity displays indicative of wind backing above wind veering suggested the presence of the split front in the observations (as did the hodographs). Detection of the passage of the split front could be discerned from temporal changes in the vertical profile of the winds, namely by the appearance of midlevel backing of the winds in VWP time–height displays. Because of the subtlety of this backing and the need to be more quantitative, a temperature advection retrieval scheme using VWP data was developed. The complex evolving structure of the split front was revealed with this technique. Results from this retrieval method were judged to be meteorologically meaningful, to exhibit excellent time–space continuity, and to compare reasonably well with the frontal structures evident in the mesoscale model forecasts. The thermal advection scheme can easily be made to function in operations, as long as there is real-time access to level II radar data. DA - 2001/2// PY - 2001/2// DO - 10.1175/1520-0434(2001)016<0035:RTDOSF>2.0.CO;2 VL - 16 IS - 1 SP - 35-55 SN - 1520-0434 ER - TY - JOUR TI - History of toxic Pfiesteria in North Carolina estuaries from 1991 to the present AU - Burkholder, JM AU - Glasgow, HB T2 - BIOSCIENCE DA - 2001/10// PY - 2001/10// DO - 10.1641/0006-3568(2001)051[0827:HOTPIN]2.0.CO;2 VL - 51 IS - 10 SP - 827-841 SN - 1525-3244 ER - TY - JOUR TI - Field emission from ultrathin coatings of AlN on Mo emitters AU - Kang, D AU - Zhirnov, , VV AU - Sanwald, RC AU - Hren, JJ AU - Cuomo, JJ T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B AB - Experiments characterizing both the physics of emission and the performance of Mo tips coated with ultrathin film of AlN were conducted. Ultrathin films of AlN with thicknesses ranging from 7 to 21 nm in 1.5 nm increments were deposited onto Mo tips by magnetron sputtering. In situ field emission measurements were performed after each deposition step. Tip radius, thickness, and morphology of AlN coating were characterized with the transmission electron microscopy. The effect of the thickness of AlN on emission was determined using a Fowler–Nordheim analysis. Various surface treatment effects were studied and measurements of maximum current and emission stability were performed, e.g., maximum current from a single Mo tip with 15 nm of AlN coating was 52 μA. DA - 2001/// PY - 2001/// DO - 10.1116/1.1340669 VL - 19 IS - 1 SP - 50-54 SN - 2166-2746 ER - TY - JOUR TI - Factors influencing planktonic, post-settlement dispersal of early juvenile blue crabs (Callinectes sapidus Rathbun) AU - Blackmon, DC AU - Eggleston, DB T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - An emerging body of literature points to post-settlement, planktonic dispersal as a key determinant of distribution and abundance patterns of aquatic organisms, yet little is known about mechanisms inducing such dispersal. Recent evidence suggests that early juvenile blue crabs (Callinectes sapidus Rathbun) may use planktonic emigration as a means of post-settlement dispersal. The goal of this study was to identify mechanisms inducing post-settlement, planktonic dispersal of early juvenile blue crabs. A combination of field mark-recapture experiments in large seagrass beds within a 2x3 km region near Oregon Inlet, North Carolina, USA, and a series of laboratory flume experiments examined the effects of day vs. night, crab size (first-second juvenile benthic instars: J1-J2 vs. third-fifth juvenile benthic instars: J3-J5), crab density and current speed on planktonic dispersal of early juvenile blue crabs. Transport of dead crabs in the flume experiment identified that planktonic dispersal was an active behavioral response rather than a passive response to increasing current speed. The experimental results demonstrated that planktonic dispersal can range from 4 to 18% under medium to high flow conditions. Planktonic dispersal of juvenile crabs is (1) an active behavioral response, (2) increased significantly with current speeds above 20 cms(-1), and (3) was higher for relatively large (J3-J5) than small (J1-J2) instars. There was a non-significant trend towards greater dispersal at night than during the day in the field experiment, and no effect of crab density on dispersal in the flume experiment. The results from this study highlight the need to consider mechanisms inducing post-settlement, planktonic dispersal when attempting to understand and predict recruitment and population dynamics of aquatic organisms, as well as when linking hydrodynamics, animal behavior and planktonic dispersal. DA - 2001/3/15/ PY - 2001/3/15/ DO - 10.1016/s0022-0981(00)00334-8 VL - 257 IS - 2 SP - 183-203 SN - 0022-0981 KW - blue crab KW - Callinectes sapidus KW - dispersal KW - mark-recapture experiment KW - post-settlement dispersal KW - planktonic emigration KW - re-circulating flume KW - Reynolds numbers KW - seagrass ER - TY - JOUR TI - Electronic structure of noncrystalline transition metal silicate and aluminate alloys AU - Lucovsky, G AU - Rayner, GB AU - Kang, D AU - Appel, G AU - Johnson, RS AU - Zhang, Y AU - Sayers, DE AU - Ade, H AU - Whitten, JL T2 - APPLIED PHYSICS LETTERS AB - A localized molecular orbital description (LMO) for the electronic states of transition metal (TM) noncrystalline silicate and aluminate alloys establishes that the lowest conduction band states are derived from d states of TM atoms. The relative energies of these states are in agreement with the LMO approach, and have been measured by x-ray absorption spectroscopy for ZrO2–SiO2 alloys, and deduced from an interpretation of capacitance–voltage and current–voltage data for capacitors with Al2O3–Ta2O5 alloy dielectrics. The LMO model yields a scaling relationship for band offset energies providing a guideline for selection of gate dielectrics for advanced Si devices. DA - 2001/9/17/ PY - 2001/9/17/ DO - 10.1063/1.1404997 VL - 79 IS - 12 SP - 1775-1777 SN - 0003-6951 ER - TY - JOUR TI - Bunyavirus infections in North Carolina white-tailed deer (Odocoileus virginianus) AU - Nagayama, J. N. AU - Komar, N. AU - Levine, J. F. AU - Biggerstaff, B. AU - Apperson, C. S. T2 - Vector Borne and Zoonotic Diseases (Larchmont, N.Y.) DA - 2001/// PY - 2001/// VL - 1 IS - 2 SP - 169-172 ER - TY - JOUR TI - Are Atlantic and Indo-Pacific populations of the rafting crab, Plagusia depressa (Fabricius), distinct? New evidence from larval morphology and mtDNA AU - Schubart, C. D. AU - Gonzalez-Gordillo, J. I. AU - Reyns, N. B. AU - Liu, H. C. AU - Cuesta, J. A. T2 - Raffles Bulletin of Zoology DA - 2001/// PY - 2001/// VL - 49 IS - 2 SP - 301-310 ER - TY - JOUR TI - Analysis of a surprise western New York snowstorm AU - Lackmann, GM T2 - WEATHER AND FORECASTING AB - Although Rochester, New York (ROC), is not located in a climatogically favored region for extreme [i.e., ≥30 cm (12 in.) 24 h−1] lake-effect snow (LES), significant [i.e., ≥15 cm (6 in.) 24 h−1] LES can occur there under specific synoptic regimes. The purposes of this study are to document synoptic conditions that are associated with significant LES in ROC and to examine a specific event in which the passage of an upper disturbance combined with a lower-tropospheric trough to produce a surprise western New York snowstorm on 26–27 November 1996. A database of 127 events in which 2-day ROC snowfall exceeded 15 cm (6 in.) was constructed for the years 1963 through 1992, inclusive. Each event was categorized as “LES” or “non-LES” on the basis of air–lake temperature difference, wind direction, and synoptic setting. Of the 127 events, 32 were classified as LES. Composites based on this 32-case sample reveal a mobile upper trough that moves from the western Great Lakes 48 h prior to the snowfall event to northern Maine 24 h after the event. All 32 cases were accompanied by either a mobile upper trough or a closed low at the 500-hPa level. An unexpected snowstorm on 26–27 November 1996 resulted in accumulations of up to 30 cm (12 in.) in parts of western New York. Nonclassical LES structures developed in a rapidly changing synoptic environment that was characterized by the passage of an intense upper-tropospheric disturbance. Model forecasts underestimated the strength of this disturbance and also the intensity of lower-tropospheric troughing over and north of Lake Ontario. The upper trough is hypothesized to have increased the inversion altitude and relative humidity in the lower troposphere, and likely contributed to the strength of lower-tropospheric troughing near Lake Ontario. Cyclonic isobaric curvature accompanying the surface trough enhanced lower-tropospheric ascent through Ekman pumping and increased the overwater fetch for boundary layer air parcels traversing Lake Ontario. Comparison of Eta Model forecasts with analyses suggests that problems with model initialization and diabatic boundary layer processes both contributed to forecast errors. DA - 2001/2// PY - 2001/2// DO - 10.1175/1520-0434(2001)016<0099:AOASWN>2.0.CO;2 VL - 16 IS - 1 SP - 99-116 SN - 0882-8156 ER - TY - JOUR TI - A borehole flowmeter investigation of small-scale hydraulic conductivity variation in the Biscayne Aquifer, Florida AU - Genereux, D AU - Guardiario, J T2 - WATER RESOURCES RESEARCH AB - Geostatistical analysis of closely spaced borehole flowmeter measurements was used to estimate the variance (2.53) and vertical and horizontal correlation lengths of ln K (0.57 and 7.3 m) in the Biscayne Aquifer, a limestone aquifer critical for Florida's water supply and for Everglades restoration efforts. The variance and correlation lengths of the Biscayne Aquifer are similar to some of the values for unconsolidated siliciclastic sediments (especially those at Columbus, Mississippi∥. The larger λ h , for the Biscayne Aquifer (7.3 m) is thought to be due at least in part to the lower lateral variability of the carbonate platform depositional environment, compared to the fluvial environments in which the siliciclastic sediments were deposited. An improved down hole packer would allow for data with finer vertical resolution; the current system is adequate for work inside well screens but cannot adequately seal many spots in open, irregular rock boreholes. Research in rock presents additional logistical difficulties but is important for addressing fundamental questions about solute transport in a wider range of geological media, beyond unconsolidated siliciclastic deposits. DA - 2001/5// PY - 2001/5// DO - 10.1029/2001WR900023 VL - 37 IS - 5 SP - 1511-1517 SN - 1944-7973 ER - TY - JOUR TI - A biophysical model of population dynamics of the autotrophic dinoflagellate Gymnodinium breve AU - Liu, G AU - Janowitz, GS AU - Kamykowski, D 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 210:101-124 (2001) - doi:10.3354/meps210101 A biophysical model of population dynamics of the autotrophic dinoflagellate Gymnodinium breve Gang Liu, Gerald S. Janowitz*, Daniel Kamykowski Department of Marine, Earth & Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA *Corresponding author. E-mail: janowitz@ncsu.edu ABSTRACT: A new model of dinoflagellate diel migratory behavior and population dynamics is presented using the Expanded Eulerian Method (Janowitz & Kamykowski 1999, Ecol Model 118:237-247) and adapting the concept of metabolism-influenced swimming orientation (Kamykowski & Yamazaki 1997, Limnol Oceanogr 42:1189-1202; Kamykowski et al. 1998a, in: Anderson et al. [eds] Physiological ecology of harmful algal blooms, Springer-Verlag, Berlin, p. 581-599; Yamazaki & Kamykowski 2000, Ecol Model 134:59-72). The model is constructed to simulate the observations in a 3 d laboratory mesocosm experiment (Kamykowski et al. 1998b, Mar Ecol Prog Ser 167:105-117; Kamykowski et al. 1998c, J Plankton Res 20:1781-1796) on autotrophic Gymnodinium breve (a red tide dinoflagellate species) under a nutrient-replete condition and in 12 h light:12 h dark cycle. A hypothesis of the acclimations of the G. breve swimming orientation and speed to the internal biochemical and physiological state and external environmental conditions is proposed. A hypothesis proposed by Kamykowski et al. (1998b) on G. breve reproduction strategy is tested in the model by considering the 2 daughter cells coming from a parent cell to differ in internal biochemical composition. The model simulations are in good agreement with the observations. Consistent with the observations, the model predicts the surface aggregation of a portion of the population during the light period with decreasing surface aggregation intensity over the 3 d period and approximately uniform vertical distribution of the population through the water column during the dark period as well as the diel convergence and divergence patterns of the mean internal cellular carbon and nitrogen between the surface cells and mid-column cells. As expected, G. breve¹s internal biochemical and physiological states have a strong influence on its migratory behavior and consequently on its population dynamics. By comparison to a simulation with a reproduction strategy producing 2 identical daughter cells, it is shown that the reproduction strategy producing 2 daughters different in biochemical composition appears to be the one adopted by all or at least a large portion of the G. breve population in the experiment. KEY WORDS: Model · Population dynamics · Dinoflagellate · Behavior Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 210. Online publication date: January 26, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research. DA - 2001/// PY - 2001/// DO - 10.3354/meps210101 VL - 210 SP - 101-124 SN - 0171-8630 KW - model KW - population dynamics KW - dinoflagellate KW - behavior ER - TY - JOUR TI - Nonmethane hydrocarbons in the rural southeast United States national parks AU - Kang, DW AU - Aneja, VP AU - Zika, RG AU - Farmer, C AU - Ray, JD T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Measurements of volatile organic compounds (VOCs) were made at three rural sites in the southeast U.S. national parks: Mammoth Cave National Park, Kentucky; Cove Mountain, Great Smoky Mountains National Park, Tennessee; and Big Meadows, Shenandoah National Park, Virginia. In 1995 the three locations were sampling sites for the Southern Oxidants Study (SOS) Nashville Intensive, and the measurements of VOCs for Shenandoah were also made under contract with the National Park Service. Starting in 1996, the National Park Service added the other two parks to the monitoring contract. Hydrocarbon measurements made during June through September for the years 1995, 1996, and 1997 were analyzed in this study. Source classification techniques based on correlation coefficient, chemical reactivity, and ratioing were developed and applied to these data. The results show that anthropogenic VOCs from automobile exhaust appeared to be dominant at Mammoth Cave National Park, and at Cove Mountain, Great Smoky Mountains National Park, but other sources were also important at Big Meadows, Shenandoah National Park. Correlation and ratio analysis based on chemical reactivity provides a basis for source‐receptor relationship. The most abundant ambient VOCs varied both in concentration and order depending on park and year, but the following VOCs appeared on the top 10 list for all three sites: isoprene (6.3 to 18.4 ppbv), propane (2.1 to 12.9 ppbv), isopentane (1.3 to 5.7 ppbv), and toluene (1.0 to 7.2 ppbv). Isoprene is naturally emitted by vegetation, and the others are produced mainly by fossil fuel combustion and industrial processes. Propylene‐equivalent concentrations were calculated to account for differences in reaction rates between the hydroxyl radical and individual hydrocarbons, and to thereby estimate their relative contributions to ozone formation. DA - 2001/2/16/ PY - 2001/2/16/ DO - 10.1029/2000JD900607 VL - 106 IS - D3 SP - 3133-3155 SN - 0747-7309 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0035081992&partnerID=MN8TOARS ER - TY - JOUR TI - Nitrate reductase activity in a submersed marine angiosperm: Controlling influences of environmental and physiological factors AU - Touchette, BW AU - Burkholder, J T2 - PLANT PHYSIOLOGY AND BIOCHEMISTRY AB - In plants, nitrate reductase (NR; EC 1.6.6.1) is considered to be a key enzyme in nitrate assimilation. Therefore, the activity of NR as influenced by major environmental factors may affect the survival of many aquatic nitrogen-limited plant species. In this study, the in vivo activity of NR following exposure to increased water-column nitrate was examined in a submersed marine angiosperm (eelgrass, Zostera marina L.). NR activity was primarily localized in new leaf tissue, and was related to light and/or soluble carbohydrate availability. Under extended periods of darkness (18 h), enzyme activity decreased by more than 60 %. Nevertheless, in vivo NR activity was induced during dark periods provided that water-column nitrate (≥ 8 μM NO3–) was available. Enzyme activities were lower in plants that were exposed to hypoxic conditions (< 3.5 mg O2·L–1 for 14 h), and/or elevated growth temperatures (3 to 4 °C above mean weekly temperatures). In contrast, exposure to the atmosphere for 90 min promoted a significant increase in in vivo NR activity. A temporal investigation (14 weeks in autumn) revealed that the intensity of in vivo NR response to water-column nitrate was directly correlated with the quantity of soluble carbohydrates within the leaf tissue. Many of the observed in vivo NR responses were likely related to carbohydrate availability. During periods where soluble carbohydrate availability was expected to be low, in vivo NR response to increased water-column nitrate was substantially compromised. DA - 2001/// PY - 2001/// DO - 10.1016/S0981-9428(01)01278-5 VL - 39 IS - 7-8 SP - 583-593 SN - 0981-9428 KW - carbon KW - eelgrass KW - light KW - nitrate reductase KW - oxygen KW - seagrass KW - Zostera marina ER - TY - PAT TI - Methods of raising reflow temperature of glass alloys by thermal treatment in steam, and microelectronic structures formed thereby AU - Croswell, R. T. AU - Reisman, A. AU - Simpson, D. L. AU - Temple, D. AU - Williams, C. K. C2 - 2001/// DA - 2001/// PY - 2001/// ER - TY - JOUR TI - Direct radiative forcing and atmospheric absorption by boundary layer aerosols in the southeastern US: model estimates on the basis of new observations AU - Yu, SC AU - Zender, CS AU - Saxena, VK T2 - ATMOSPHERIC ENVIRONMENT AB - In an effort to reduce uncertainties in the quantification of aerosol direct radiative forcing (ADRF) in the southeastern United States (US), a field column experiment was conducted to measure aerosol radiative properties and effects at Mt. Mitchell, North Carolina, and at an adjacent valley site. The experimental period was from June 1995 to mid-December 1995. The aerosol optical properties (single scattering albedo and asymmetry factor) needed to compute ADRF were obtained on the basis of a procedure involving a Mie code and a radiative transfer code in conjunction with the retrieved aerosol size distribution, aerosol optical depth, and diffuse-to-direct solar irradiance ratio. The regional values of ADRF at the surface and top of atmosphere (TOA), and atmospheric aerosol absorption are derived using the obtained aerosol optical properties as inputs to the column radiation model (CRM) of the community climate model (CCM3). The cloud-free instantaneous TOA ADRFs for highly polluted (HP), marine (M) and continental (C) air masses range from 20.3 to −24.8, 1.3 to −10.4, and 1.9 to −13.4 W m−2, respectively. The mean cloud-free 24-h ADRFs at the TOA (at the surface) for HP, M, and C air masses are estimated to be −8±4 (−33±16), −7±4 (−13±8), and −0.14±0.05 (−8±3) W m−2, respectively. On the assumption that the fractional coverage of clouds is 0.61, the annual mean ADRFs at the TOA and the surface are −2±1, and −7±2 W m−2, respectively. This also implies that aerosols currently heat the atmosphere over the southeastern US by 5±3 W m−2 on annual timescales due to the aerosol absorption in the troposphere. DA - 2001/8// PY - 2001/8// DO - 10.1016/S1352-2310(01)00187-X VL - 35 IS - 23 SP - 3967-3977 SN - 1352-2310 KW - aerosol radiative forcing KW - column radiation model KW - southeastern US KW - observation KW - aerosol absorption ER - TY - JOUR TI - Determination of specific yield for the Biscayne Aquifer with a canal-drawdown test AU - Bolster, CH AU - Genereux, DP AU - Saiers, JE T2 - GROUND WATER AB - Data from a large-scale canal-drawdown test were used to estimate the specific yield (sy) of the Biscayne Aquifer, an unconfined limestone aquifer in southeast Florida. The drawdown test involved dropping the water level in a canal by about 30 cm and monitoring the response of hydraulic head in the surrounding aquifer. Specific yield was determined by analyzing data from the unsteady portion of the drawdown test using an analytical stream-aquifer interaction model (Zlotnik and Huang 1999). Specific yield values computed from drawdown at individual piezometers ranged from 0.050 to 0.57, most likely indicating heterogeneity of specific yield within the aquifer (small-scale variation in hydraulic conductivity may also have contributed to the differences in sy among piezometers). A value of 0.15 (our best estimate) was computed based on all drawdown data from all piezometers. We incorporated our best estimate of specific yield into a large-scale two-dimensional numerical MODFLOW-based ground water flow model and made predictions of head during a 183-day period at four wells located 337 to 2546 m from the canal. We found good agreement between observed and predicted heads, indicating our estimate of specific yield is representative of the large portion of the Biscayne Aquifer studied here. This work represents a practical and novel approach to the determination of a key hydrogeological parameter (the storage parameter needed for simulation and calculation of transient unconfined ground water flow), at a large spatial scale (a common scale for water resource modeling), for a highly transmissive limestone aquifer (in which execution of a traditional pump test would be impractical and would likely yield ambiguous results). Accurate estimates of specific yield and other hydrogeological parameters are critical for management of water supply, Everglades environmental restoration, flood control, and other issues related to the ground water hydrology of the Biscayne Aquifer. DA - 2001/// PY - 2001/// DO - 10.1111/j.1745-6584.2001.tb02368.x VL - 39 IS - 5 SP - 768-777 SN - 0017-467X ER - TY - JOUR TI - Density-dependent predation, habitat variation, and the persistence of marine bivalve prey AU - Seitz, RD AU - Lipcius, RN AU - Hines, AH AU - Eggleston, DB T2 - ECOLOGY AB - The persistence of prey encountering intense predation varies by species, prey density, and habitat type; however, the collective impact of these factors has rarely been tested experimentally in natural marine systems. Using the thin-shelled clams Mya arenaria and Macoma balthica as prey, and the main epibenthic predator of whole adult clams, the blue crab Callinectes sapidus, we conducted a series of experiments in Chesapeake Bay tributaries that (1) links field abundance and distribution of bivalve prey species with habitat-specific mortality patterns; (2) represents the first comprehensive field test of species-specific, habitat-specific, and density-dependent mortality for subtidal, soft-bottom, deep-burrowing prey; and (3) thereby enables development of a conceptual model to be used as a heuristic tool linking predator–prey dynamics, habitat type, and evolutionary defense tactics for marine benthos. In 15 years of field monitoring, Mya was more common in sand than mud habitats, and Macoma was widely distributed and at higher densities than Mya in mud and sand. In field experiments, mortality of both Mya and Macoma was density dependent in those habitats where the clams are common. The blue crab population in the field exhibited a type III “guild functional response” on Mya in sand, and on Macoma in both mud and sand. Mortality was lower in sand than mud for Mya, and similar in mud and sand for Macoma, correlating with the high abundances of Mya in sand and Macoma in sand and mud. The persistence of large juvenile and adult bivalves when confronted with intense predation derived substantially from a low-density refuge from predation that varied in a species-specific manner with habitat type, demonstrating the species-specific importance of density and habitat to clam survival. We developed a conceptual model detailing the relative importance of behavior, morphology, habitat features, and the basic components of predator–prey interactions to the survival of bivalve molluscs. At one extreme are bivalve molluscs, such as oysters, that emphasize morphological refuges that increase the predator's handling time. At the other extreme are bivalves, such as Mya and Macoma, that reduce predator encounter rates. The model is intended to be used as a heuristic tool to develop testable hypotheses. DA - 2001/9// PY - 2001/9// DO - 10.2307/2679927 VL - 82 IS - 9 SP - 2435-2451 SN - 1939-9170 KW - armor vs. avoidance KW - bivalves KW - blue crab KW - Callinectes sapidus KW - density dependence KW - sigmoid functional response KW - habitat type KW - Macoma balthica KW - Mya arenaria KW - predation KW - predator avoidance KW - low-density refuge from predation ER - TY - PCOMM TI - Atmospheric pressure helium plasma treatment of ultrahigh modulus polyethylene fibres AU - Qiu, Y. AU - Anantharamaiah, N. AU - Xie, S. AU - Vaidya, N. P. AU - Zhang, C. DA - 2001/// PY - 2001/// SP - 135-139 ER - TY - JOUR TI - Assimilating surface data to improve the accuracy of atmospheric boundary layer simulations AU - Alapaty, K AU - Seaman, NL AU - Niyogi, DS AU - Hanna, AF T2 - JOURNAL OF APPLIED METEOROLOGY AB - Large errors in atmospheric boundary layer (ABL) simulations can be caused by inaccuracies in the specification of surface characteristics in addition to assumptions and simplifications made in boundary layer formulations or other model deficiencies. For certain applications, such as air quality studies, these errors can have significant effects. To reduce such errors, a continuous surface data assimilation technique is developed. In this technique, surface-layer temperature and water vapor mixing ratio are directly assimilated by using the analyzed surface data. Then, the difference between the observations and model results is used to calculate adjustments to the surface fluxes of sensible and latent heat. These adjustments are then used to calculate a new estimate of the ground temperature, thereby affecting the simulated surface fluxes on the subsequent time step. This indirect data assimilation is applied simultaneously with the direct assimilation of surface data in the model's lowest layer, thereby maintaining greater consistency between the ground temperature and the surface-layer mass-field variables. A one-dimensional model was used to study the improvements that result from applying this technique for ABL simulations in two cases. It was found that application of the new technique led to significant reductions in ABL modeling errors. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0450(2001)040<2068:ASDTIT>2.0.CO;2 VL - 40 IS - 11 SP - 2068-2082 SN - 0894-8763 ER - TY - JOUR TI - Reproductive potential of individual male blue crabs, Callinectes sapidus, in a fished population: depletion and recovery of sperm number and seminal fluid AU - Kendall, MS AU - Wolcott, DL AU - Wolcott, TG AU - Hines, AH T2 - CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES DA - 2001/6// PY - 2001/6// DO - 10.1139/cjfas-58-6-1168 VL - 58 IS - 6 SP - 1168-1177 SN - 1205-7533 ER - TY - JOUR TI - Multiple taxon-multiple locality approach to providing oxygen isotope evidence for warm-blooded theropod dinosaurs: Comment AU - Barrick, R. E. AU - Kohn, M. J. T2 - Geology (Boulder, Colo.) DA - 2001/// PY - 2001/// VL - 29 IS - 6 SP - 565-566 ER - TY - JOUR TI - Mechanistic model simulations of the East African climate using NCAR regional climate model: Influence of large-scale orography on the Turkana low-level jet AU - Indeje, M AU - Semazzi, FHM AU - Xie, L AU - Ogallo, LJ T2 - JOURNAL OF CLIMATE AB - The National Center for Atmospheric Research regional climate model (RegCM) is employed to study the dynamics of the Turkana low-level jet that lies between the Ethiopian and the East African highlands, and also investigate the mechanisms responsible for the observed dry conditions over the Lake Turkana basin that lies in the wider section of the Turkana channel. The role of the large-scale orography and two other forcing factors namely the large-scale monsoonal flow and the Turkana channel depth are investigated in order to understand the kinematics of the jet. The simulated patterns of the Turkana easterly low-level jet compares well with its observed characteristics. Strong winds are indicated in the channel throughout the study period of October to December, with the wind speed decreasing in the middle and wider region of the channel. A split in the jet core is also shown in the middle of the channel. The level of maximum winds (∼11 m s−1) occurs in the layers 930-hPa and 650-hPa levels. The dynamics of the Turkana channel is explained in terms of the orographic channeling effects associated with the Bernoulli theorem as applied to barotropic steady and nonviscous flows. The main results on the forcing mechanisms responsible for the development of the jet can be summarized as follows: (a) orographic forcing is the most important factor, (b) the large-scale monsoon background flow is important in determining the wind speed in the jet cores, (c) the depth of the channel determines the vertical structure and location of the jet cores, and (d) thermal and frictional forcing play equivalent role as that of the large-scale background winds in the formation and maintenance of the jet. Divergence and anticyclonic vorticity partly explains the observed split in the jet cores in the middle of the channel. The dry conditions observed over the Lake Turkana basin are explained in terms of dominant downward vertical velocity, decrease in moisture flux convergence, and increase in temperature flux divergence that inhibit active developments of mesoscale circulations and their interactions with large-scale flow over these areas. The identified regions of strong winds associated with the jet are important to the safety in the aviation industry. These regions may also provide alternative renewable energy resources in the form of wind energy. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0442(2001)014<2710:MMSOTE>2.0.CO;2 VL - 14 IS - 12 SP - 2710-2724 SN - 1520-0442 ER - TY - JOUR TI - Identification of a P2X7 receptor in GH(4)C(1) rat pituitary cells: A potential target for a bioactive substance produced by Pfiesteria piscicida AU - Kimm-Brinson, KL AU - Moeller, PDR AU - Barbier, M AU - Glasgow, H AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/5// PY - 2001/5// DO - 10.2307/3454703 VL - 109 IS - 5 SP - 457-462 SN - 1552-9924 KW - c-fos KW - GH(4)C(1) KW - P2X7 KW - Pfiesteria KW - pituitary KW - purinergic KW - toxin ER - TY - JOUR TI - Aerosol optical depth measurements and their impact on surface levels of ultraviolet-B radiation AU - Wenny, BN AU - Saxena, VK AU - Frederick, JE T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Surface measurements of total and diffuse UV irradiance at the seven narrowband wavelength channels of the ultraviolet multifilter rotating shadow‐band radiometer (UVMFR) were used to determine total column ozone and aerosol optical depth for two 6‐month periods in 1997 and 1999 at a site in the Blue Ridge Mountains of North Carolina. The retrieved column ozone displayed a seasonal dependence and consistent agreement with the Total Ozone Mapping Spectrometer (TOMS). The mean ratio of retrieved ozone to TOMS ozone was 0.98 with standard deviations of 0.02 and 0.01 for 1997 and 1999, respectively. Aerosol optical depth at 317, 325, 332, and 368 nm was derived for a 6‐month period of 1999. The seasonal trend exhibited is influenced by the persistent summertime haze that occurs in the region. The retrieved aerosol optical depths are used as input in a radiative transfer model to investigate the effect of their realistic values on the calculation of the UV index (UVI) forecasted by the National Weather Service. The percentage change in calculated surface erythemally weighted UV (versus calculations using the standard UVI aerosol inputs) ranges from a 4% increase to a nearly 50% decrease, dependent upon the aerosol optical depth and amount of absorption by aerosols. Based on our measurements, it was found that during the summertime the UV index can deviate by up to −5 index units from the forecast using the standard aerosol inputs. DA - 2001/8/16/ PY - 2001/8/16/ DO - 10.1029/2001JD900185 VL - 106 IS - D15 SP - 17311-17319 SN - 2169-8996 ER - TY - JOUR TI - A comparison of signals of regional aerosol-induced forcing in eastern China and the southeastern United States AU - Yu, SC AU - Saxena, VK AU - Zhao, ZC T2 - GEOPHYSICAL RESEARCH LETTERS AB - This paper compares the temperature change patterns and the signals of regional aerosol‐induced forcing in eastern China and the southeastern US during the latter half of the twentieth century. Both regions show decreasing trends in the mean maximum temperature over recent decades and the cooling effect of Pinatubo volcanic aerosols. In contrast to the southeastern US, we found a slight overall warming trend in eastern China. Our analysis suggests that in addition to greenhouse warming effect, observed high concentrations of absorbing aerosols over eastern China during winter and spring might be one of the major reasons for the observed warming trend. DA - 2001/2/15/ PY - 2001/2/15/ DO - 10.1029/2000GL011834 VL - 28 IS - 4 SP - 713-716 SN - 0094-8276 ER - TY - JOUR TI - Measurement and analysis of atmospheric ammonia emissions from anaerobic lagoons AU - Aneja, VP AU - Bunton, B AU - Walker, JT AU - Malik, BP T2 - ATMOSPHERIC ENVIRONMENT AB - Ammonia-nitrogen flux (NH3-N=(14/17)NH3) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (∼15 cm below the surface), lagoon water pH, total aqueous phase NHx(=NH3+NH4+) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3°C. The pH ranged in value from 6.8 to 8.1. Aqueous NHx concentration ranged from 37 to 909 mg N l−1, and TKN varied from 87 to 950 mg N l−1. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m−2 min−1, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m−2 min−1. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NHx concentration. The NH3-N flux may be modeled as ln(NH3-N flux)=1.0788+0.0406TL+0.0015([NHx]) (R2=0.74), where NH3-N flux is the ammonia flux from the lagoon surface in μg N m−2 min−1, TL is the lagoon surface water temperature in °C, and [NHx] is the total ammonia-nitrogen concentration in mg N l−1. DA - 2001/// PY - 2001/// DO - 10.1016/S1352-2310(00)00547-1 VL - 35 IS - 11 SP - 1949-1958 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0035126691&partnerID=MN8TOARS KW - ammonia KW - ammonia emission KW - swine waste lagoon KW - dynamic chamber ER - TY - JOUR TI - Atmospheric nitrogen compounds II: emissions, transport, transformation, deposition and assessment AU - Aneja, VP AU - Roelle, PA AU - Murray, GC AU - Southerland, J AU - Erisman, JW AU - Fowler, D AU - Asman, WAH AU - Patni, N T2 - ATMOSPHERIC ENVIRONMENT AB - The Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment workshop was held in Chapel Hill, NC from 7 to 9 June 1999. This international conference, which served as a follow-up to the workshop held in March 1997, was sponsored by: North Carolina Department of Environment and Natural Resources; North Carolina Department of Health and Human Services, North Carolina Office of the State Health Director; Mid-Atlantic Regional Air Management Association; North Carolina Water Resources Research Institute; Air and Waste Management Association, RTP Chapter; the US Environmental Protection Agency and the North Carolina State University (College of Physical and Mathematical Sciences, and North Carolina Agricultural Research Service). The workshop was structured as an open forum at which scientists, policy makers, industry representatives and others could freely share current knowledge and ideas, and included international perspectives. The workshop commenced with international perspectives from the United States, Canada, United Kingdom, the Netherlands, and Denmark. This article summarizes the findings of the workshop and articulates future research needs and ways to address nitrogen/ammonia from intensively managed animal agriculture. The need for developing sustainable solutions for managing the animal waste problem is vital for shaping the future of North Carolina. As part of that process, all aspects of environmental issues (air, water, soil) must be addressed as part of a comprehensive and long-term strategy. There is an urgent need for North Carolina policy makers to create a new, independent organization that will build consensus and mobilize resources to find technologically and economically feasible solutions to this aspect of the animal waste problem. DA - 2001/// PY - 2001/// DO - 10.1016/S1352-2310(00)00543-4 VL - 35 IS - 11 SP - 1903-1911 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0034744409&partnerID=MN8TOARS KW - ammonia KW - nitrogen compounds KW - emissions KW - effects KW - transport KW - transformation KW - swine operations and abatement ER - TY - JOUR TI - A particle introduction experiment in Santa Catalina Basin sediments: Testing the age-dependent mixing hypothesis AU - Fornes, WL AU - DeMaster, DJ AU - Smith, CR T2 - JOURNAL OF MARINE RESEARCH AB - The occurrence of age-dependent mixing, a process by which recently deposited, food-rich particles undergo more intense bioturbation than older, food-poor particles, could dramatically alter patterns of organic-matter diagenesis in deep-sea sediments. To explicitly test for age-dependent mixing, an in-situ particle introduction experiment was conducted on the bathyal Santa Catalina Basin floor. Mixtures of radioisotope-tagged particles representing a food quality gradient were dispersed in small amounts on the seafloor and sampled over periods of 0 to 594 days. Introduced particle types were all similar in size and included fresh diatoms (young particles), surface sediments (intermediate-age particles), and particles from 30-cm deep in the sediment column (old particles). This approach permitted evaluation of particle mixing intensity for several particle ages and provided an independent check on mixing coefficients determined from naturally occurring radioisotopes ( 234 Th xs and 210 Pb xs ). All particles experienced rapid (<6 h) transport into the upper 2 cm of the seabed resulting from passive deposition down burrows or extremely rapid bioturbation. Intense bioturbation on 4-d time scales included both biodiffusive and nondiffusive (bioadvective and nonlocal) transport. Bioturbation of tracers exhibited time (or age) dependence in two ways: (1) Diffusive mixing intensity for all tracer types decreased with time (4-d D b = 293 cm 2 y -1 , D b at 520 d = 2.6 cm 2 y -1 ), and (2) The nature of bioturbation changed over this period with more efficient bioadvection and nonlocal exchange giving way to slower diffusive mixing. Both changes are consistent with the age-dependent-mixing hypothesis. Biodiffusive mixing was not measurably selective, with no significant preference for a single particle type. In contrast, nondiffusive transport, likely caused by deposit-feeding cirratulid polychaetes, exhibited distinct particle selectivity, especially over 4-d time scales, with the diatom tracer transported most rapidly to depth. Degradation of the labile organic carbon in diatoms most likely led to decreasing selection of diatoms by deposit feeders until diatoms and old sediment particles experienced comparable mixing intensities. DA - 2001/1// PY - 2001/1// DO - 10.1357/002224001321237380 VL - 59 IS - 1 SP - 97-112 SN - 0022-2402 ER - TY - JOUR TI - The role of tonalite and diorite in Mauna Kea volcano, Hawaii, magmatism: Petrology of summit-region leucocratic xenoliths AU - Fodor, RV T2 - JOURNAL OF PETROLOGY AB - A tonalite (∼66 wt % SiO2; 2·4 wt % K2O) xenolith from the Mauna Kea summit region provides information on the origin of silicic liquids in mafic magma systems. This leucocratic rock has ∼40 vol. % quartz interstitial to and enclosing Ca-andesine, plus phlogopite (∼11 vol. %), clinopyroxene (mg-number ∼74), orthopyroxene, and Fe–Ti oxides. Also, it contains lithic fragments (≤5 cm) of gabbro (MgO 7·2 wt %; An60–50; clinopyroxene mg-number ∼78–75; phlogopite). The tonalite has Sr–Nd–Pb isotopic ratios of 87Sr/86Sr 0·703610, 144Nd/143Nd 0·512976, 206Pb/204Pb 18·58, 207Pb/204Pb 15·49, and 208Pb/204Pb 38·15, which agree with the isotopic composition of Mauna Kea post-shield Hamakua Volcanics (tholeiitic and alkalic basalts). A positive Eu anomaly and poikilitic texture indicate a cumulate origin. Leucocratic diorite (∼50–53 wt % SiO2; 1–2·4 wt % K2O) xenoliths coexist with the tonalite. These have intergranular andesine–oligoclase (∼68–85 vol. % of An50–15), evolved clinopyroxene (mg-number 76–69), and biotite (± orthopyroxene, zircon). The tonalite represents SiO2-rich liquids that accumulated, perhaps in a small reservoir, after segregation from a hydrous basalt-magma solidification front; gabbro inclusions within the tonalite are probably remnants of that source. Hydrous conditions (implied by abundant phlogopite) were necessary for this silicic-liquid segregation; namely, relatively high H2O facilitated crystallization of SiO2-deficient phases (oxide; phlogopite) to leave SiO2-enriched residual liquids, and H2O vapor pressure helped segregate silicic liquids by gas-pressured filter pressing. The diorites are coarse-grained equivalents of hawaiite and mugearite produced by clinopyroxene-dominant crystallization of Hamakua alkalic basalt. On the basis of normative Ol–Di–Ne, diorite xenoliths originated under intermediate and high pressures, apparently reflecting the transition from low- to high-P crystallization regimes that are identified for Mauna Kea post-shield magmas (where the high-P regime is approximately at the crust–mantle boundary). Leucocratic xenoliths, particularly tonalite, provide additional insights into Hamakua post-shield magma evolution by manifesting differentiation that is more extensive and complex, approaching granitic compositions, than that represented by Hamakua lavas, and by showing that quartz can crystallize appreciably during Hawaiian magmatism. Quartz-bearing rock on Hawaii has global relevance in terms of providing better understanding of the circumstances for oceanic basalt–rhyolite magmatism. DA - 2001/9// PY - 2001/9// DO - 10.1093/petrology/42.9.1685 VL - 42 IS - 9 SP - 1685-1704 SN - 0022-3530 KW - xenoliths KW - tonalite KW - diorite KW - gabbro KW - Mauna Kea, cumulate, quartz ER - TY - JOUR TI - The identification, conservation, and management of estuarine and marine nurseries for fish and invertebrates AU - Beck, MW AU - Heck, KL AU - Able, KW AU - Childers, DL AU - Eggleston, DB AU - Gillanders, BM AU - Halpern, B AU - Hays, CG AU - Hoshino, K AU - Minello, TJ AU - Orth, RJ AU - Sheridan, PF AU - Weinstein, MR T2 - BIOSCIENCE AB - Michael W. Beck, Kenneth L. Heck, Jr., Kenneth W. Able, Daniel L. Childers, David B. Eggleston, Bronwyn M. Gillanders, Benjamin Halpern, Cynthia G. Hays, Kaho Hoshino, Thomas J. Minello, Robert J. Orth, Peter F. Sheridan and Michael P. Weinstein DA - 2001/8// PY - 2001/8// DO - 10.1641/0006-3568(2001)051[0633:TICAMO]2.0.CO;2 VL - 51 IS - 8 SP - 633-641 SN - 1525-3244 ER - TY - JOUR TI - A numerical study of wave-current interaction through surface and bottom stresses: Wind-driven circulation in the South Atlantic Bight under uniform winds AU - Xie, LA AU - Wu, KJ AU - Pietrafesa, L AU - Zhang, C T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - The influences of surface waves on ocean currents in the coastal waters of the South Atlantic Bight are investigated by using a coupled wave‐current modeling system. The ocean circulation model employed is the three‐dimensional Princeton Ocean Model (POM), and the wave model invoked is an improved third‐generation wave model (WAM). The coupling procedure between the POM and the WAM and the simulated coastal ocean circulation driven by uniform surface winds are presented. The simulated results show that wind waves can significantly affect coastal ocean currents not only through an enhancement of wind stress but also through a modification of bottom stress. Wave‐induced wind stress increases the magnitude of currents both at the surface and near the seabed. On the other hand, wave‐induced bottom stress weakens the currents both at the sea surface and near the seabed. Therefore the net effect of surface wind waves on currents depends on the relative importance of current modulations by wave‐induced wind stress and bottom stress. The results further indicate that at a fixed location, the relative importance of wave‐induced surface and bottom shear stresses in coastal ocean circulation depends on the surface wind field. For the constant wind cases considered in this study, the effect of wave‐induced bottom stress is more significant in along‐shore wind conditions than in cross‐shore wind conditions. DA - 2001/8/15/ PY - 2001/8/15/ DO - 10.1029/2000JC000292 VL - 106 IS - C8 SP - 16841-16855 SN - 2169-9291 ER - TY - JOUR TI - A further study of the mechanisms of cell regeneration, propagation, and development within two-dimensional multicell storms AU - Lin, YL AU - Joyce, LE T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - The mechanisms of cell regeneration, development, and propagation within a two-dimensional multicell storm proposed by Lin, Deal, and Kulie (hereafter LDK) were further investigated by conducting a series of sensitivity tests. LDK's advection mechanism was reexamined by performing simulations utilizing a plateau with five additional wind profiles having a wider range of shear. All five cases gave results that show that the cell regeneration period decreases with the storm-relative midlevel inflow, similar to that proposed by LDK. It was also found that a rigid lid is not an appropriate upper boundary condition for multicell storm simulations. In order to test whether the advection mechanism is responsible for cell regeneration with a different sounding, an idealized sounding was used. A multicell storm was produced along with a strong density current and gust front updraft. Investigation of this storm supports the advection mechanism within the growing mode and a gravity wave mechanism in the propagation mode, as proposed by LDK. From further investigation, the relaxation mechanism proposed by Fovell and Tan was shown to exist within these simulations yet found to be dependent on the advection mechanism to cause cell regeneration. To avoid some problems that occurred when using a plateau, a prescribed heat sink was used to produce a more realistic density current. This experiment demonstrates that the advection mechanism is responsible for cell regeneration and the gravity wave mechanism is responsible for cell propagation within the storm. It was found that without precipitation loading, an individual cell is still able to split. In this case, the compensating downdraft produced by vertical differential advection is responsible for cell splitting and merging. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0469(2001)058<2957:AFSOTM>2.0.CO;2 VL - 58 IS - 20 SP - 2957-2988 SN - 0022-4928 ER - TY - JOUR TI - Overview and present status of the toxic Pfiesteria complex (Dinophyceae) AU - Burkholder, JM AU - Glasgow, HB AU - Deamer-Melia, N T2 - PHYCOLOGIA AB - This paper reviews the Pfiesteria issue and Pfiesteria science and presents new information on variation in toxicity among Pfiesteria strains, culture effects on their toxicity, the trophic interactions of Pfiesteria spp ., and impacts on fish and mammals. We also assess Pfiesteria spp. impacts on fish in comparison to certain other estuarine dinoflagellates of similar appearance. Species of the toxic Pfiesteria complex (TPC) thus far include P. piscicida and P. shumwayae. These species share morphological and genetic similarities, and both have toxic strains that (1) show strong attraction to live fish;(2) exhibit toxicity that is triggered by live fish or their fresh tissues and excreta; and (3) produce toxin(s) that cause fish stress, disease and death under ecologically relevant conditions (the standardized fish bioassay process involves testing live Pfiesteria cells at similar densities to those encountered during Pfiesteria-related fish kill/disease events). Both Pfiesteria species also have a complex life cycle with multiple amoeboid, flagellated and cyst stages, several of which are ichthyotoxic. TPC species are eurythermal and euryhaline, with prey spanning the estuarine food web, from bacteria to mammalian tissues. They can be stimulated directly or indirectly by nitrogen and phosphorus enrichment. Toxic strains can be either actively or potentially toxic (the TOX-A and TOX-B functional types, respectively); in addition, c.40% of randomly isolated clones have been found to be benign [the noninducible or NON-IND functional type, which apparently lacks the ability to produce bioactive substances (toxins) that cause fish disease or death]. These functional types differ significantly in response to algal prey, predators, nutrients and fish. Moreover, as an apparent artifact of culture conditions, toxic strains generally lose their ability to cause fish death and disease and become NON-IND within weeks to months. At low cell densities, toxic strains can be causative agents of acute and/or chronic diffuse and focal lesions and of other fish diseases, as demonstrated in fish bioassays. A partially purified, water-soluble Pjiesteria toxin disrupts calcium metabolism in rat pituitary cells and mimics an adenosine triphosphate neurotransmitter that targets P2X7 purinoreceptors found predominantly on immune cells. Respiratory, visual, and neurological impacts have been sustained by people exposed to aerosols from fish-killing Pfiesteria cultures or to water and aerosols during estuarine fish kills associated with toxic Pfiesteria. Neurocognitive impacts from exposure to toxic Pfiesteria have been replicated experimentally in small mammals. Toxic strains of Pfiesteria species have been confirmed from mid-Atlantic and Gulf Coast estuaries in the United States and from northern Europe and New Zealand, indicating that these toxic dinoflagellates are cosmopolitan in distribution. DA - 2001/5// PY - 2001/5// DO - 10.2216/i0031-8884-40-3-186.1 VL - 40 IS - 3 SP - 186-214 SN - 2330-2968 ER - TY - JOUR TI - A second species of ichthyotoxic Pfiesteria (Dinamoebales, Dinophyceae) AU - Glasgow, HB AU - Burkholder, JM AU - Morton, SL AU - Springer, J T2 - PHYCOLOGIA AB - A second toxic species within the family Pfiesteriaceae, Pfiesteria shumwayae Glasgow & Burkholder sp. nov., is described from the New River Estuary and the Neuse Estuary of the Albemarle-Pamlico Estuarine Ecosystem, USA. The species is polymorphic and multiphasic, with flagellated, amoeboid and cyst stages. The flagellated zoospores (diameter 8–24 μm) have permanently condensed chromosomes (mesokaryotic nucleus); a chrysophyte-like cyst (diameter 6–25 μm)with organic scales and bracts; and thin thecal plates arranged in a Kofoidian series of Po, cp, X, 4′, la, 6″, 6c, 4s, 5″′, 2″″. The benthic filopodial (filose), lobopodia1 (lobose) and rhizopodial amoeboid stages (5–250 μm) have an outer covering that ranges from rough to smooth in texture, depending on the stage of origin and the prey source. Pfiesteria shumwayae amoebae have a normal eukaryote nucleus and cysts of multiple sizes (diameter 4–25 μm) with a reticulate outer covering. Toxic strains of the two Pfiesteria species have overlapping distributions in the mid-Atlantic and southeastern United States and Scandinavia, with toxic P. shumwayae also having been verified from New Zealand. Pfiesteria shumwayae is similar to P. piscicida in its complex life cycle, general nutrition, attraction to live fish prey, and ichthyotoxic activity that is stimulated by the presence of live fish or their fresh tissues and excreta. However, it can be distinguished from P. piscicida morphologically by having six precingular plates and a four-sided la plate, as well as genetically, on the basis of its ISS ribosomal DNA sequence. DA - 2001/5// PY - 2001/5// DO - 10.2216/i0031-8884-40-3-234.1 VL - 40 IS - 3 SP - 234-245 SN - 2330-2968 ER - TY - JOUR TI - Numerical investigation of lake bed seepage patterns: effects of porous medium and lake properties AU - Genereux, D AU - Bandopadhyay, I T2 - JOURNAL OF HYDROLOGY AB - Three-dimensional steady-state numerical models were used to investigate the relative significance of several factors controlling lake bed seepage patterns: lake depth, lake bed slope, orientation of an asymmetric lake with respect to a regional hydraulic gradient, lake bed sediments, and heterogeneity and anisotropy of the porous medium. We considered both inflow and flow-through lakes, and our focus was on the details of seepage flux at the lake bed (not on the surrounding porous medium). While porous medium factors (anisotropy and heterogeneity) are important, we found several conditions where lake bed factors were nearly as important in controlling the distribution of seepage. Varying lake bed slope from 0.013 to 0.04 in different simulations had a significant effect on shoreline seepage (rates were 10–40% higher for lakes of low slope than lakes of steep slope). Also, significantly elevated seepage (in some cases, a local maximum) was observed offshore at the break in bed slope between the sloping side and flat central portions of the lake bed, whenever the surrounding porous medium had a high anisotropy (1000 or 100). For flow-through lakes in media of high anisotropy, the annual volume of groundwater inseepage was significantly higher (about 20%) in lakes with steep bed slope compared to those with low slope; this effect of slope was smaller at lower anisotropy. For an asymmetric flow-through lake (a lake with a steep bed slope on one side, moderate slope on the other) the percentage of lake bed experiencing inseepage was greatest when the steep side was downgradient, and the effect was larger at higher anisotropy. These effects illustrate the complex interaction between lake bed slope and the anisotropy of the surrounding porous medium in controlling lake:groundwater exchange. Adding low-conductivity lake sediments, and decreasing their conductivity, shifted groundwater seepage further offshore in inflow lakes; increasing the anisotropy of the surrounding porous medium had the same effect. Adding sediments and increasing anisotropy also decreased nearshore seepage in flow-through lakes, but without increasing offshore seepage; in this case, the net effect was a smaller annual volume of lake:groundwater exchange. At the same time, the percentage of the lake bed experiencing inseepage increased in flow-through lakes, even as the annual volume of inseepage was decreasing. Thus, for flow-through lakes, a larger area of inseepage may not be a good indicator of a greater volume of inseepage. Lake depth did not have a significant effect on the quantity or distribution of seepage to inflow or flow-through lakes. Many of the physical factors investigated here influence the amount of lake:groundwater exchange and the proportions of nearshore and offshore seepage; therefore, they are potentially significant to lake water quality and ecology in addition to hydrology. DA - 2001/1/31/ PY - 2001/1/31/ DO - 10.1016/s0022-1694(00)00380-2 VL - 241 IS - 3-4 SP - 286-303 SN - 0022-1694 KW - lake KW - groundwater KW - seepage KW - hydrology KW - surface water KW - aquifer ER - TY - JOUR TI - Biogenic nitric oxide emissions from cropland soils AU - Roelle, PA AU - Aneja, VP AU - Gay, B AU - Geron, C AU - Pierce, T T2 - ATMOSPHERIC ENVIRONMENT AB - Emissions of nitric oxide (NO) were determined during late spring and summer 1995 and the spring of 1996 from four agricultural soils on which four different crops were grown. These agricultural soils were located at four different sites throughout North Carolina. Emission rates were calculated using a dynamic flow-through chamber system coupled to a mobile laboratory for in-situ analysis. Average NO fluxes during late spring 1995 were: 50.9±47.7 ng N m−2 s−1 from soil planted with corn in the lower coastal plain. Average NO fluxes during summer 1995 were: 6.4±4.6 and 20.2±19.0 ng N m−2 s−1, respectively, from soils planted with corn and soybean in the coastal region; 4.2±1.7 ng N m−2 s−1 from soils planted with tobacco in the piedmont region; and 8.5±4.9 ng N m−2 s−1 from soils planted with corn in the upper piedmont region. Average NO fluxes for spring 1996 were: 66.7±60.7 ng N m−2 s−1 from soils planted with wheat in the lower coastal plain; 9.5±2.9 ng N m−2 s−1 from soils planted with wheat in the coastal plain; 2.7±3.4 ng N m−2 s−1 from soils planted with wheat in the piedmont region; and 56.1±53.7 ng N m−2 s−1 from soils planted with corn in the upper piedmont region. An apparent increase in NO flux with soil temperature was present at all of the locations. The composite data from all the research sites revealed a general positive trend of increasing NO flux with soil water content. In general, increases in total extractable nitrogen (TEN) appeared to be related to increased NO emissions within each site, however a consistent trend was not evident across all sites. DA - 2001/// PY - 2001/// DO - 10.1016/S1352-2310(00)00279-X VL - 35 IS - 1 SP - 115-124 SN - 1352-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0035238856&partnerID=MN8TOARS KW - nitric oxide KW - biogenic emissions KW - dynamic chamber KW - agricultural soils ER - TY - JOUR TI - Thermohaline feedback loops and natural capital AU - Hopkins, T. S. T2 - Scientia Marina DA - 2001/// PY - 2001/// VL - 65 IS - 2001 Sep SP - 231-256 ER - TY - JOUR TI - Species of the toxic Pfiesteria complex, and the importance of functional type in data interpretation AU - Burkholder, JM AU - Glasgow, HB AU - Deamer-Melia, NJ AU - Springer, J AU - Parrow, MW AU - Zhang, C AU - Cancellieri, PJ T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454912 VL - 109 SP - 667-679 SN - 1552-9924 KW - amoebae KW - complex life cycle KW - culture KW - dinoflagellates KW - estuaries KW - fish KW - noninducible KW - nutrients KW - strains KW - toxic Pfiesteria complex ER - TY - JOUR TI - Some common ingredients for heavy orographic rainfall AU - Lin, YL AU - Chiao, S AU - Wang, TA AU - Kaplan, ML AU - Weglarz, RP T2 - WEATHER AND FORECASTING AB - The purpose of this paper is to synthesize some common synoptic and mesoscale environments conducive to heavy orographic rainfall. Previous studies of U.S. and Alpine cases and new analyses of some Alpine and east Asian cases have shown the following common synoptic and mesoscale environments are conducive to heavy orographic rainfall: 1) a conditionally or potentially unstable airstream impinging on the mountains, 2) a very moist low-level jet (LLJ), 3) a steep mountain, and 4) a quasi-stationary synoptic system to slow the convective system over the threat area. A deep short-wave trough is found to approach the threat area in the U.S. and European cases, but is not found in the east Asian cases. On the other hand, a high convective available potential energy (CAPE) value is observed in east Asian cases, but is not consistently observed in the U.S. and European cases. The enhancement of low-level upward motion and the increase of instability below the trough by the approaching deep short-wave trough in the U.S. and Alpine events may partially compensate the roles played by high CAPE in the East Asian events. In addition, the concave mountain geometry plays an important role in helping trigger the convection in Alpine and Taiwanese cases. Based on an ingredient argument, it is found that a heavy orographic rainfall requires significant contributions from any combinations of the above four common synoptic and mesoscale environments or ingredients, and high precipitation efficiency of the incoming airstream, strong upward motion, and large convective system. These ingredients are also used to help explain the synoptic and mesoscale environments observed in some orographic flooding and heavy rainfall events in other regions, such as in New Zealand, China, and India. An index, U(∂h/∂x)q, where U is the flow velocity perpendicular to the mountain range, ∂h/∂x the mountain slope, and q the water vapor mixing ratio, is also proposed to help predict the occurrence of heavy orographic rainfall. Estimates of this proposed index indicate that it may serve as a good indicator for predicting east Asian heavy orographic rainfall events. DA - 2001/// PY - 2001/// DO - 10.1175/1520-0434(2001)016<0633:SCIFHO>2.0.CO;2 VL - 16 IS - 6 SP - 633-660 SN - 0882-8156 ER - TY - JOUR TI - Role of Behavior in meeting osmotic challenges AU - Wolcott, TG AU - Wolcott, DL T2 - AMERICAN ZOOLOGIST AB - Biologists must remember that physiology is the product of natural selection on organisms interacting with heterogeneous environments. “Behaving” organisms may alter the osmotic conditions they experience and achieve results unexpected from laboratory studies. Their ability to exploit environmental heterogeneity depends on its temporal/spatial scale relative to that of the organism, and the correspondence between the osmotic differences and the organism's sensory and osmoregulatory physiology. “Behaviors” include evasion of stressful habitats, selection among differing microenvironments, changing body characteristics that affect salt/water uptake/loss, manipulating fluids differing in osmolytes, and modification of osmotic microenvironments (especially for vulnerable offspring). To draw “comparative and integrative” inferences, investigators must strive to understand an organism's actual challenges by “seeing” the world from its perspective, and then making observations and performing experiments in the context of the “real world” experienced by that organism. DA - 2001/9// PY - 2001/9// DO - 10.1668/0003-1569(2001)041[0795:ROBIMO]2.0.CO;2 VL - 41 IS - 4 SP - 795-805 SN - 0003-1569 ER - TY - JOUR TI - On the mass and salt budgets for a region of the continental shelf in the southern Mid-Atlantic Bight AU - Kim, YY AU - Weatherly, GL AU - Pietrafesa, LJ T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - Two field studies were conducted across and along the continental shelf, one from February to May 1996 (deployment 1) and the other from July to October 1996 (deployment 2) in part to determine the mass and salt budgets of shelf water from south of Cape Henry to north of Cape Hatteras, the southernmost portion of the Mid‐Atlantic Bight. The temporal means of current meter records indicated that most of the water enters the region across its northern boundary near the shelf break as part of a southward, alongshore current and exits the southeast corner as a southeastward flowing current. Estimates of the volume transports indicated that not all the transport across the northern boundary was accounted for by transport across the southern boundary and that the remainder occurred as a broad, diffusive flow across the eastern boundary at the shelf break. Time series of volume transport across northern and southern boundaries were very similar and associated with variations in the alongshore wind stress and sea level, indicative of a geostrophic balance. Examination of the individual current meter records indicated these fluctuations were very barotropic even during deployment 2, which included the stratified summer season. Time series of the volume transport across the eastern boundary at the shelf break strongly mirrored the volume transport across the northern boundary minus that across the southern boundary, suggesting that the inferred eastern boundary transport was real and accommodated whatever the southern boundary could not. The turbulent salt flux across each boundary contributes very little to the net salt flux. The mean and time‐dependent salt fluxes show nearly identical patterns as the respective mass fluxes because the salt fluxes are almost governed by current velocity fields. The instantaneous and mean salt fluxes across each boundary were very well approximated by the instantaneous and mean volume transports across the boundary times the deployment average salinity across that boundary, respectively. The Ocean Margins Program (OMP) moored current and salinity observations appear sufficient to make estimates of the mean and time‐dependent mass and salt balance. DA - 2001/12/15/ PY - 2001/12/15/ DO - 10.1029/2000JC000738 VL - 106 IS - C12 SP - 31263-31282 SN - 2169-9291 ER - TY - JOUR TI - Effect of environmental variables on NO emissions from agricultural soils AU - Aneja, V.P. AU - Roelle, P.A. AU - Li, Y. T2 - Phyton - Annales Rei Botanicae DA - 2001/// PY - 2001/// VL - 41 IS - 3 SP - 29-40 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0035521253&partnerID=MN8TOARS ER - TY - JOUR TI - An assessment of hygroscopic growth factors for aerosols in the surface boundary layer for computing direct radiative forcing AU - Im, JS AU - Saxena, VK AU - Wenny, BN T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Aerosol optical properties in the southeastern United States were measured at two research sites in close horizontal proximity but at different altitudes at Black Mountain (35.66 °N, 82.38 °W, 951 m msl) and Mount Gibbes (35.78 °N, 82.29 °W, 2006 m msl) to estimate the direct radiative forcing in the lowest 1 km layer of the troposphere during the summer of 1998. Measurements of light scattering and light absorption at ambient relative humidity (RH) are categorized by air mass type (polluted continental, marine with some continental influence, continental) according to 48‐hour back‐trajectory analysis. At a wavelength of 530 nm the average total scattering coefficient (σ sp ) measured at the valley site was 1.46×10 −4 m −1 for polluted continental air masses, 7.25×10 −5 m −1 for marine air masses, and 8.36×10 −5 m −1 for continental air masses. The ratio of σ sp at the mountain site to σ sp at the valley site was 0.64, 0.58, and 0.45 for polluted continental, marine, and continental air masses, respectively. The hygroscopic growth factor (σ sp (RH = 80%)/σ sp (RH = 30%)) was calculated to be almost a constant value of 1.60±0.01 for polluted continental, marine, and continental air masses. As the RH increased from 30% to 80%, the backscatter fraction decreased by 23%. On the basis of these measurements, direct radiative climate forcing (Δ F R ) by aerosols in the lowest 1 km layer of the troposphere was estimated. The patterns of Δ F R for various values of RH were similar for the three air masses, but the magnitudes of Δ F R (RH) were larger for polluted continental air masses than for marine and continental air masses by a factor of about 2 due to higher sulfate concentration in polluted continental air masses. The average value of Δ F R (RH = 80%)/Δ F R (RH = 30%) was calculated to be almost a constant value of 1.45±0.01 for all three types of air masses. This implies little dependence of the forcing ratio on the air mass type. The averaged Δ F R for all the observed ambient RHs, in the lowest 1 km layer during the 3‐month summer period, was −2.95 W m −2 (the negative forcing of −3.24 W m −2 by aerosol scattering plus the positive forcing of +0.30 W m −2 by aerosol absorption) for polluted continental air masses, −1.43 W m −2 (−1.55 plus +0.12) for marine air masses, and −1.50 W m −2 (−1.63 plus +0.14) for continental air masses. The Δ F R for polluted continental air masses was approximately twice that of marine and continental air masses. These forcing estimates are calculated from continuous in situ measurements of scattering and absorption by aerosols without assumptions for Mie calculations and global mean column burden of sulfates and black carbon (in g m −2 ) used in most of the model computations. DA - 2001/9/16/ PY - 2001/9/16/ DO - 10.1029/2000JD000152 VL - 106 IS - D17 SP - 20213-20224 SN - 2169-8996 ER - TY - JOUR TI - A GCM study of climate change induced by deforestation in Africa AU - Semazzi, FHM AU - Song, Y T2 - CLIMATE RESEARCH AB - CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 17:169-182 (2001) - doi:10.3354/cr017169 A GCM study of climate change induced by deforestation in Africa Fredrick H. M. Semazzi1,2,*, Yi Song1 1Department of Marine, Earth and Atmospheric Sciences and 2Department of Mathematics, North Carolina State University, Raleigh, North Carolina 27695, USA *E-mail: fred_semazzi@ncsu.edu ABSTRACT: In this modeling study we investigated the potential climate change which would result from totally clearing the tropical rain forests in Africa. The primary research vehicle in our investigation was the standard version of the National Center for Atmospheric Research (NCAR) CCM3 global climate model (GCM), with a horizontal resolution of triangular spectral truncation T42 (approximately 2.8° x 2.8°). Two separate 10 yr simulations were performed; for each of these the global climatological sea surface temperature field was prescribed. The purpose of the 10 yr simulations was to provide a sufficiently large ensemble whose average minimizes model noise errors. In the control simulation normal vegetation was prescribed. The design of the anomaly experiment was similar to the control run except that the tropical rainforest regions in Africa were replaced by savanna grassland vegetation. The CCM3 GCM successfully simulated the primary features of the seasonal mean climate conditions over Africa. The model results show that replacement of tropical rain forest vegetation with savanna grassland vegetation produces the following climate changes over Africa: (1) Over the deforested region, the model results indicate a significant reduction in area-averaged rainfall throughout the year. The decrease ranges between 2 to 3 mm d-1 during the northern hemispheric summer months, when the region experiences the driest conditions (July to September), and less than 1 mm d-1 during the wettest months (autumn and spring). (2) Over southern Africa deforestation results in substantial rainfall reduction over Mozambique and rainfall increase over Botswana, Zambia, the southern region of the Democratic Republic of the Congo, and parts of South Africa. Changes in the trapped Rossby wave train activity generated by the mid-tropospheric latent heating over the tropical forest region are responsible for the continental-scale teleconnection climate response. (3) Over Eastern and Western Africa the impact of deforestation is primarily characterized by a reduction in rainfall, however the adopted GCM T42 resolution may not have been adequate to resolve the large contrasts in terrain and vegetation types. (4) Over the rest of Africa the response is relatively weak. KEY WORDS: Climate change · Deforestation · Climate of Africa · Climate modelling Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 17, No. 2. Online publication date: August 15, 2001 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2001 Inter-Research. DA - 2001/8/15/ PY - 2001/8/15/ DO - 10.3354/cr017169 VL - 17 IS - 2 SP - 169-182 SN - 0936-577X KW - climate change KW - deforestation KW - climate of Africa KW - climate modelling ER - TY - JOUR TI - Watershed control on the carbon loading of marine sedimentary particles AU - Leithold, EL AU - Blair, NE T2 - GEOCHIMICA ET COSMOCHIMICA ACTA AB - Previous investigations of the factors governing organic carbon burial on continental margins have pointed toward the important, apparently protective association of carbon with mineral particles. These studies have also revealed dramatic transformations of carbon-particle relationships at the land-sea interface. Riverine particles in some settings lose a large portion of their loads of sorbed terrestrial carbon upon discharge to the ocean and gradually reload to similar levels with marine carbon. The Eel River in northern California and the adjacent continental shelf were selected as an ideal system to investigate the rates of these processes. The river is episodically subject to large floods, and the shelf stratigraphy preserves a record of the resultant large pulses of sediment and carbon input to the marine environment. Carbon isotopic, carbon to nitrogen, and carbon to surface area ratios of particles in flood deposits were expected to reflect the rapid unloading of terrestrial carbon from discharged particles, whereas nonflood sediments that have accumulated at slower rates on the shelf were expected to carry higher loads of marine carbon. Our results indicate, however, that particles on the Eel shelf have retained their loads of terrigenous carbon, and that a significant portion of the particle-sorbed carbon buried on the shelf is kerogen derived from the Mesozoic-Tertiary Franciscan Complex. We hypothesize that rates of uplift and mass wasting in the Eel watershed and rates of particle delivery to and burial on the continental shelf, are so rapid that kerogen is not completely oxidized and is recycled instead. The loading of carbon on clay-sized particles delivered to the shelf, moreover, is dependent on river discharge and may reflect the relative importance of different mass wasting processes during precipitation events of varying intensity. The Eel River system is likely to be representative of other small, mountainous rivers and indicates that processes on land may play an important role in governing the amount and character of carbon being buried on the continental margins. DA - 2001/7// PY - 2001/7// DO - 10.1016/S0016-7037(01)00593-2 VL - 65 IS - 14 SP - 2231-2240 SN - 0016-7037 ER - TY - JOUR TI - A study on the performance of a triple nested mesoscale model over tropical Indian Ocean during INDOEX AU - Roswintiarti, O. AU - Raman, S. AU - Mohanty, U. C. AU - Niyogi, D. S. T2 - Current Science DA - 2001/// PY - 2001/// VL - 80 IS - 2001 Apr. 10 SP - 77-84 ER -