2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
6/08/2017 | 2:30 PM - 2:45 PM | BOTTOM-UP VERSUS TOP-DOWN CONTROLS ON PHYTOPLANKTON: AN IN-SITU MICROCOSM STUDY AS A COLLABORATIVE LABORATORY EXERCISE. | 301A
BOTTOM-UP VERSUS TOP-DOWN CONTROLS ON PHYTOPLANKTON: AN IN-SITU MICROCOSM STUDY AS A COLLABORATIVE LABORATORY EXERCISE.
We use 20 L clear plastic water containers as microcosms deployed in a local pond after manipulating nitrogen, phosphorus or microcrustacean zooplankton densities in replicate containers. Sets of replicate containers are filled with (1) lake water (controls); (2) lake water plus phosphorus or nitrogen (+P or +N treatment); (3) lake water poured through a zooplankton net to remove microcrustacean zooplankton (-Z treatment); (4) filtered lake water plus we add phosphorus (+P/-Z treatment). Sets of 4 containers (one of each treatment) are attached to buoys and left in the pond for 4 weeks (usually 4-6 replicates/treatment). When containers are retrieved, students quantify phosphorus concentrations (500 ml sample), we take 1-2 L samples for phytoplankton quantification (chlorophyll a analysis or we do phytoplankton identification and enumeration), and they filter the rest of the water in the containers (~18 L) through a zooplankton net to determine zooplankton densities. This exercise has been done as a collaborative lab between classes in introductory biology, ecology, and phycology. We have observed both bottom-up and top-down controls with these experiments. Data will be presented from several iterations of this experiment.
- S11 Scholarship of Teaching and Learning in Freshwater Science
- S25 Do mesocosm experiments play a meaningful role in freshwater research
- S11 Scholarship of Teaching and Learning in Freshwater Science
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Presenters/Authors
Randy Fuller
(), Colgate University, rfuller@colgate.edu;
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