کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4545928 1327478 2008 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
“Windows of opportunity” for dinoflagellate blooms: Reduced microzooplankton net growth coupled to eutrophication
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم آبزیان
پیش نمایش صفحه اول مقاله
“Windows of opportunity” for dinoflagellate blooms: Reduced microzooplankton net growth coupled to eutrophication
چکیده انگلیسی
Links between eutrophication, plankton community structure, microzooplankton grazing and dinoflagellate abundance were investigated in two tributaries of the Chesapeake Bay, the Choptank and Patuxent Rivers (MD, USA). Sampling and experiments were conducted during the spring of consecutive dry (below average freshwater flow) and wet (above average freshwater flow) years. During the wet year (2003), dissolved inorganic nitrogen, phytoplankton, and copepod biomass, but not microzooplankton abundance, were greater than in the dry year. In 2003, but not 2002, small cell size photosynthetic dinoflagellates were abundant and blooms occurred in both rivers. Average potential microzooplankton grazing pressure on small dinoflagellates was spatially and temporally variable, but was not significantly different between years. Our data suggest that the variability in microzooplankton grazing pressure provided “windows of opportunity” for net growth of dinoflagellates in response to nutrient loading. The lack of net population growth of micrograzers in response to increases in dinoflagellate prey allowed dinoflagellate blooms to reach relatively high densities, however grazing also appeared to be important in limitation or demise of some blooms. We hypothesize that uncoupling of micrograzer-prey dynamics was partly due to strong top-down control by copepods of microzooplankton in the proportionately more eutrophic year, and perhaps also due to inhibition of microzooplankton grazing/growth once dinoflagellate densities are high.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Harmful Algae - Volume 8, Issue 1, December 2008, Pages 158-166
نویسندگان
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