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Abstract Book INTERACTIONS ON THE EDGE Abstract Book Abstract Book ASLO/SCL/NABS Acharya, K., Desert Research Institute, Las Vegas, USA, [email protected]; Agboola, J. I., Hokkaido University, Graduate School of Environmental Bukaveckas, P. A., Virginia Commonwealth University, Richmond, USA, Science, Sapporo, Japan, [email protected]; [email protected] Kudo, I., Hokkaido University, Graduate School of Environmental Science, UNIFORM VS. HETEROGENEOUS DIET: WHICH ONE DOES Sapporo, Japan; ZOOPLANKTON FAVOR? Uchimiya, M., Hokkaido University, Sapporo, Japan In nature, the zooplankton diet is most likely to be heterogeneous in nature SPATIO-TEMPORAL ANALYSES OF NUTRIENTS AND as it is composed of particles with different nutrient and biochemical PHYTOPLANKTON BIOMASS IN SUB-ARTIC COASTAL contents. Most research on zooplankton dietary implications is based on ENVIRONMENT OF JAPAN. treatments in which all food particles are treated equal in nutrient and The distribution of nutrients and phytoplankton biomass (Chla ) are reported biochemical contents. In this study, we compared several studies done and related to the oceanographic conditions in spring, summer and autumn, on various species of Daphnia (pulicaria, galeata, lumholtzi, magna) and and in-plume and out-plume regions on the Ishikari Bay, Japan. Nutrients Bosmina feeding on many diet types such as seston, algal amended seston, distribution in surface waters was characterized by the general tendency to uniform algae, and mixed algae of high and low qualities. In most cases, decrease from spring to autumn, and plume to out-plume region. In spring, juvenile growth rate and fecundity were measured but in some cases when the in-sea diffusion of nutrients was highest, total Chla ) biomass was long term growth and mortality were also measured. Overall the results at par in plume (2.30 mg m-3) and out-plume (2.39 mg m-3) region. Marked suggested that all the species of Daphnia performed better in laboratory seasonal differences in size fractions were also observed. When the water grown, uniform algae over seston or heterogeneous algae of equivalent column was strongly stratified and nutrient concentrations were low at nutrient and biochemical contents. Most dietary constraints seemed surface in summer, average total Chl a values were 0.80 mg m-3 and 0.38 mg to arise from either the nutrient or the biochemical limitation. Our m-3 respectively in plume and out-plume regions. In autumn, the intrusion experiments also suggested that algal amended seston provided a better of nutrients into the plume region by intense vertical mixing and riverine diet than seston alone. However, the magnitude of the impact differed on inputs produced an increase of the total autotrophic biomass (7.36 mg m-3). different species. This study illustrates how changes in environmental gradients of the coastal system in time and space are affected by seawater dilution, vertical mixing, Ackerman, D., SCCWRP, Costa Mesa, USA, [email protected] biological activities and light attenuation. MODELING CLIMATE CHANGE AND SEA LEVEL RISE IN WATERSHEDS AND ESTUARIES Agustí, S., IMEDEA CSIC-UIB, Esporles, Mallorca, Spain, [email protected]; Duarte, C. M., IMEDEA CSIC-UIB, Esporles, Mallorca, Spain, [email protected]; Climate change and sea level rise have the potential to dramatically affect a Llabrés, M., IMEDEA CSIC-UIB, Esporles, Mallorca, Spain, [email protected]; wide range of coastal habitats. As the climate changes, the hydrology and Kennedy, H., School of Ocean Sciences, University of Wales, Bangor, sediment transport from coastal watersheds will likely be different than United Kingdom the current conditions. These differences along with changes in sea level and tidal range have the potential to affect the structure and function of RESPONSE OF COASTAL ANTARCTIC PHYTOPLANKTON TO coastal estuaries and the species that depend on them. Linked watershed- SOLAR RADIATION AND NUTRIENT MANIPULATION: AN IN SITU estuary models provide a tool to assess the impact of both terrestrial and MESOCOSM EXPERIMENT oceanic forcing (on coastal watersheds and estuaries. Models can be used Despite the HNLC situation described for Antarctic waters, coastal areas to evaluate a range of future scenarios on a variety of wetland systems. We are susceptible to develop large phytoplankton blooms, which are not applied this approach to approximately 50 estuaries in southern California. predictable. To test the role of solar irradiance and nutrient inputs on Given the number of distinct estuaries, we developed synthetic models phytoplankton bloom formation in Antarctic coastal waters we performed representing categories of southern California coastal watersheds and a large-scale, in situ, mesocosm experiment in Sur Bay (Livingston Island, estuaries. This enables results to be generalized across a broad range of South Shetlands, Antarctica). Phytoplankton growth, nutrient use and conditions and localities and not tied to specific areas. In this study, we biomass development remained low at reduced light and at ambient modeled the hydrology and sediment transport from three synthetic coastal irradiances, and increased greatly (> 30 fold) to yield large phytoplankton watersheds and estuaries. The effect of those loadings on estuary circulation, blooms in response to moderate shading. Nutrient additions (ammonium) hydrodynamics and sediment transport were also simulated. The results greatly stimulated (> one order-of-magnitude) phytoplankton growth, from the models will enable managers to quantify a spectrum of possible biomass, and nutrient use at ambient irradiances, and lead to a decline watershed and estuary responses to future climate and sea level conditions. in the specific UV absorption by MAAs, indicative of an alleviation from stress derived from high UV and irradiance. Switching experimental Adams, H. E., University of Michigan, Ann Arbor, USA, [email protected]; treatments confirmed the role of nutrient additions in a second phase of Crump, B. C., University Maryland Center for Environmental Science, the experiment. These results suggest a narrow window of irradiance where Horn Point Laboratory, Cambridge, USA, [email protected]; phytoplankton could develop blooms in the coastal Antarctica. Kling, G. W., University of Michigan, Ann Arbor, USA, [email protected] DOWNSTREAM DISPERSAL AND ACTIVITY OF BACTERIA. Albertin, A., University of Florida, Gainesville, USA, [email protected]; Sickman, J. O., University of California, Riverside, USA, [email protected]; Bacterioplankton communities disperse into downstream habitats via Pinowska, A., Michigan State, East Lansing , USA, [email protected]; advective flow along with carbon subsidies from upstream habitats. Stevenson, R. J., Michigan State, East Lansing , USA, [email protected]; Persistence of communities in downstream habitats depends on residence Anderson, M., University of Florida, Gainesville, USA, ytramnosredna@ time and species sorting processes such as competition based on available yahoo.com carbon sources. The combined influence of transient bacterial communities and associated carbon subsidies on resident downstream communities STABLE ISOTOPE COMPOSITIONS OF MACROALGAE, SEDIMENT is poorly understood. To compare the activity of transient and resident AND NITRATE IN FLORIDA SPRINGS bacterial populations, we performed in situ transplant experiments using The aquifers supplying water to Florida’s more than 700 karst springs are dialysis bags in which bacteria from the inlet and outlet streams of a susceptible to human activities and land use change. While nitrate levels have headwater lake were incubated in both environments during periods of low increased in most springs over the last 30 years, no quantitative relationship and high hydrologic connectivity (stream flow). Molecular fingerprinting exists between nitrate concentrations and biomass of macroalgae, making indicated communities were very different at the two sites (~45% similarity) it difficult to establish protective nutrient criteria to prevent nuisance algal and showed little change in composition during incubations. Inlet bacteria blooms in these springs. In order to determine nitrate and carbon sources had equal or increased activity when transplanted to the lake outlet while to benthic macroalgal mats, the stable isotopes of macroalgae and spring the outlet bacteria had depressed activity at the inlet, regardless of flow sediments (δ15N and δ13C) as well as nitrate in spring water (δ15N and conditions. This indicates that transient, newly dispersed bacteria are still δ18O) were measured at three scales: (1) regionally, at multiple springs active in downstream habitats while resident lake bacteria have decreased throughout Florida; (2) along four spring-river runs and; (3) within thick activity on carbon that is transported from upstream. algal mats (>1m) at individual springs. Multiple factors are likely affecting ASLO/SCL/NABS 008 ASLO Summer Meeting δ13C values in macroalgae. The regional and gradient studies showed distinct Illinois. Body size differed among lakes, with no lake exhibiting the full species-specific δ13C compositions, which may be indicative of an algae’s regional range of variation. Resource quality was not a significant indicator relative uptake of and degree of availability for CO2 (aq) vs. HCO3- ion of among-lake differences in body size. However, phenotypic variation in as a carbon source, which, in turn were controlled by pH. Unlike δ13C, the field is determined both by genetics and the specific environmental
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