PARENT SESSION
Contributed Oral Session 35: Invasive Species: Great Lakes Area
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 524 B, Level 5, Palais des congrès de Montréal
Low P and High F: Testing for stoichiometric and ecosystem effects of phosphorus abatement and bivalve filtration.
Schulz, Kimberly*,1, Mayer, Christine2, Ji, Xinli1, Qin, Peibing3, 1 SUNY College of Environmental Science and Forestry, Syracuse, NY2 University of Toledo, Toledo, OH3 Syracuse University, Syracuse, NY
ABSTRACT- Several large-scale anthropogenic changes over the past decade have dramatically increased water clarity and light penetration in many North American lakes. First, phosphorus regulation to control eutrophication has successfully lowered P inputs (low P), and likely decreased total pelagic productivity. Second, the high filtration capability of exotic Dreissena (high F) has greatly decreased phytoplankton standing stocks. Low P and high F conditions that increase water clarity and decrease nutrient availability should not only shift energy to benthic production, but also decrease the nutrient content of pelagic and benthic primary producers, thereby altering both the amount and quality of food available to consumers. During summer 2004 we ran a large mesocosm experiment at the Cornell Biological Field Station on Oneida Lake, in which we manipulated light, phosphorus loading and dreissenid abundance in a fully factorial design, to separate the potentially synergistic effects of nutrient abatement and Dreissena filtration on benthic and pelagic primary producers. We found that both light and Dreissena significantly altered pelagic and benthic primary production, nutrient content, and community composition; phosphorus was less important in this still eutrophic system (Oneida Lake). Dreissena and light also altered the relative importance of benthic and primary production, the pool sizes of carbon, nitrogen and phosphorus, the presence of nuisance filamentous algae, and the importance of the pelagic microbial loop. We compare our mesocosm results with whole-lake changes. The implications of these changes for food quantity and quality available for secondary consumers will also be discussed.
Key words: ecological stoichiometry, benthic-pelagic coupling, light, Dreissena