TY - JOUR TI - Quantifying environmental stress induced emissions of algal isoprene and monoterpenes using laboratory measurements AU - Meskhidze, N. AU - Sabolis, A. AU - Reed, R. AU - Kamykowski, D. T2 - Biogeosciences Discussions AB - Abstract. We report here production rates of isoprene and monoterpene compounds (α-pinene, β-pinene, camphene and d-limonene) from six phytoplankton monocultures as a function of irradiance and temperature. Irradiance experiments were carried out for diatom strains – Thalassiosira weissflogii and Thalassiosira pseudonana; prymnesiophyte strains – Pleurochrysis carterae; dinoflagellate strains – Karenia brevis and Prorocentrum minimum; cryptophyte strains – Rhodomonas salina, while temperature experiments were carried out for diatom strains – Thalassiosira weissflogii and Thalassiosira pseudonana. Phytoplankton species, incubated in a climate-controlled room, were subject to variable light (90 to 900 μmol m−2s−1) and temperature (18 to 30 °C) regimes. Compared to isoprene, monoterpene emissions were an order of magnitude lower at all light and temperature levels. Emission rates are normalized by cell count and Chlorophyll a (Chl a) content. Diatom strains were the largest emitters, with ~2x1017g (cell)−1h−1 (~35 μg (g Chl a)−1h−1) for isoprene and ~5x10−19 g (cell)−1h−1 (~1μg (g Chl a)−1) h−1) for α-pinene. The contribution to the total monoterpene production was ~70% from α-pinene, ~20% for d-limonene, and <10% for camphene and β -pinene. Phytoplankton species showed a rapid increase in production rates at low (<150 μmol m−2s−1) and a gradual increase at high (>250 μmol m−2s−1) irradiance. Measurements revealed different patterns for time-averaged emissions rates over two successive days. On the first day most of the species showed distinct increase in production rates within the first four hours, while on the second day the emission rates were overall higher, but less variable. The data suggest that enhanced amounts of isoprene and monoterpenes are emitted from phytoplankton as a result of perturbations in environmental conditions that cause disbalance in chloroplasts and forces primary producers to acclimate physiologically. This relationship could be a valuable tool for development of dynamic ecosystem modeling approaches for global marine isoprene and monoterpene emissions based on phytoplankton physiological responses to a changing environment. DA - 2014/9/19/ PY - 2014/9/19/ DO - 10.5194/bgd-11-13533-2014 VL - 11 IS - 9 SP - 13533-13570 J2 - Biogeosciences Discuss. LA - en OP - SN - 1810-6285 UR - http://dx.doi.org/10.5194/bgd-11-13533-2014 DB - Crossref ER - TY - CHAP TI - Examining Material Transport in Dynamic Coastal Environments: An Integrated Approach Using Field Data, Remote Sensing and Numerical Modeling AU - Miller, Richard L. AU - López, Ramón AU - Mulligan, Ryan P. AU - Reed, Robert E. AU - Liu, Cheng-Chien AU - Buonassissi, Christopher J. AU - Brown, Matthew M. T2 - Remote Sensing and Modeling AB - Coastal environments are critical ecological systems and offer vital resources and functions to societies worldwide. As a major interface between terrestrial and ocean environments, coastal water bodies (rivers, estuaries, bays and coastal margins) provide key ecological services and are the major conduit and processors of terrestrially derived particulate and dissolved material as they are transported to the ocean. Consequently, coastal environments have been shown to play a major role in global bio-geochemical cycles and provide critical habitat for a host of marine species. Globally, these important environments are under considerable pressure from high population densities, increasing growth rates and are particularly vulnerable from the effects of projected climate change such as sea level rise and increased storm events. Despite their importance, significant gaps remain in our understanding of how these environments will respond to climate change, increasing human population, land use changes, and over exploitation of natural resources. This lack of understanding is due in part to the difficulties in developing effective monitoring and analysis programs using only a single measurement approach that is limited in its spatial and temporal coverage. We describe an integrated approach based on field measurements, remote sensing and numerical modeling that is being developed to examine the transport of dissolved (colored dissolved organic matter (CDOM), dissolved organic carbon (DOC)) and particulate material (total suspended matter (TSM)) within a complex coastal system, the Albemarle-Pamlico Estuarine System (APES), North Carolina USA. This integrated approach was established to overcome limitations associated with a single measurement and analysis approach. Field measurements and discrete samples are acquired using well-established protocols from small boats, bridges, and from the shore. Remotely sensed data are obtained from several sensors with diverse capabilities including SeaWiFS, MODIS, MERIS, HICO, Landsat and FORMOSAT-2. The numerical model Delft3D is used to simulate freshwater and DOC transport in the estuaries following major rainfall events that lead to high river discharge. Challenges associated with examining the APES using a single vs. an integrated measurement approach along with representative results from a broad suite of measurements are presented. Future advances in technology and refinements in our integrated approach are also considered. PY - 2014/// DO - 10.1007/978-3-319-06326-3_14 SP - 333-364 OP - PB - Springer International Publishing SN - 9783319063256 9783319063263 UR - http://dx.doi.org/10.1007/978-3-319-06326-3_14 DB - Crossref ER - TY - JOUR TI - pH-induced flocculation, indirect electrocoagulation, and hollow fiber filtration techniques for harvesting the saltwater microalga Dunaliella AU - Mixson, Stephanie M. AU - Stikeleather, Larry F. AU - Simmons, Otto D., III AU - Wilson, Cameron W. AU - Burkholder, JoAnn M. T2 - JOURNAL OF APPLIED PHYCOLOGY DA - 2014/8// PY - 2014/8// DO - 10.1007/s10811-013-0232-z VL - 26 IS - 4 SP - 1701-1709 SN - 1573-5176 KW - Biofuel KW - Dunaliella KW - pH-induced flocculation KW - Electrocoagulation KW - Fatty acids (FAs) KW - Hollow fiber filtration KW - Lipids ER - TY - JOUR TI - The role of mixotrophic protists in the biological carbon pump AU - Mitra, A. AU - Flynn, K. J. AU - Burkholder, J. M. AU - Berge, T. AU - Calbet, A. AU - Raven, J. A. AU - Graneli, E. AU - Glibert, P. M. AU - Hansen, P. J. AU - Stoecker, D. K. AU - Thingstad, F. AU - Tillmann, U. AU - Vage, S. AU - Wilken, S. AU - Zubkov, M. V. T2 - BIOGEOSCIENCES AB - Abstract. The traditional view of the planktonic food web describes consumption of inorganic nutrients by photoautotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at the foundation of most models used to explore biogeochemical cycling, functioning of the biological pump, and the impact of climate change on these processes. We suggest an alternative new paradigm, which sees the bulk of the base of this food web supported by protist plankton communities that are mixotrophic – combining phototrophy and phagotrophy within a single cell. The photoautotrophic eukaryotic plankton and their heterotrophic microzooplankton grazers dominate only during the developmental phases of ecosystems (e.g. spring bloom in temperate systems). With their flexible nutrition, mixotrophic protists dominate in more-mature systems (e.g. temperate summer, established eutrophic systems and oligotrophic systems); the more-stable water columns suggested under climate change may also be expected to favour these mixotrophs. We explore how such a predominantly mixotrophic structure affects microbial trophic dynamics and the biological pump. The mixotroph-dominated structure differs fundamentally in its flow of energy and nutrients, with a shortened and potentially more efficient chain from nutrient regeneration to primary production. Furthermore, mixotrophy enables a direct conduit for the support of primary production from bacterial production. We show how the exclusion of an explicit mixotrophic component in studies of the pelagic microbial communities leads to a failure to capture the true dynamics of the carbon flow. In order to prevent a misinterpretation of the full implications of climate change upon biogeochemical cycling and the functioning of the biological pump, we recommend inclusion of multi-nutrient mixotroph models within ecosystem studies. DA - 2014/// PY - 2014/// DO - 10.5194/bg-11-995-2014 VL - 11 IS - 4 SP - 995-1005 SN - 1726-4189 ER -