2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/21/2018 | 11:00 AM - 11:15 AM | SEASONAL PATTERNS IN ALGAL BIOMASS ALTER THE STOICHIOMETRY OF EXTRACELLULAR ENZYME MEDIATED NUTRIENT CYCLING IN AN AGRICULTURALLY INFLUENCED OXBOW LAKE | 321
SEASONAL PATTERNS IN ALGAL BIOMASS ALTER THE STOICHIOMETRY OF EXTRACELLULAR ENZYME MEDIATED NUTRIENT CYCLING IN AN AGRICULTURALLY INFLUENCED OXBOW LAKE
Four years of water column nutrient, sediment, chlorophyll a (chl. a) and extracellular enzyme activity (EEA) data from an oxbow lake were examined to quantify stoichiometric responses of EEA to seasonal patterns in algal biomass. Chl. a was limited by sediment concentrations exceeding 120 mg/L, primarily in winter and spring. Scaling relationships between beta-glucosidase (BG), beta-N-acetylglucosaminindase (NAG) + l-leucine aminopeptidase (LAP) and acid phosphatase (AP) activity were all significant. Scaling relationship slopes were significantly greater for BG vs NAG+LAP and BG vs AP activities indicating that metabolism of organic C was upregulated more than N or P when chl. a exceeded 65 µg/L . Slopes for NAG+LAP vs AP activity were not different for chl. a categories representing < 100 µg/L. Yet, when chl. a exceeded 100 µg/L the slope was significantly lower, indicating an increasing reliance on organic P metabolism to meet nutrient demands during period of high productivity. Results demonstrate that seasonal patterns in light limitation and algal biomass contribute to stoichiometric patterns of EEA expression and suggest that these nutrient cycling pathways are influenced by autotroph-heterotroph interactions within eutrophic oxbow lakes.
- Biogeochemistry
- Lentic
- Nutrients
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Presenters/Authors
Jason M. Taylor
(), USDA, Agricultural Research Service, National Sedimentation Lab, jason.taylor@ars.usda.gov;
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