Water Resources Research Act Program

Details for Project ID 2020OH143B

What role does nutrient cycling by zooplankton play in supporting HAB production in western Lake Erie?

Institute: Ohio
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $35,572 Total Non-Federal Funds: $35,867

Principal Investigators: James Hood

Abstract: Harmful algal blooms (HAB) have increased in severity in western Lake Erie over the past two decades, with significant ecological, public healthand economic consequences. Although spring phosphorus (P)-loading from the Maumee River is a strong predictor of summer bloom extent, it is not clear how this P is stored and cycled prior to and during bloom formation.This lack of mechanistic understanding increases uncertainty associated with efforts to predict and mitigate HAB, particularly under future climate change or nutrient loading scenarios. We propose to examine one relatively unexamined, but potentially quantitatively important aspect of internal nutrient cycling–zooplankton-mediated nutrient recycling. Previous research on zooplankton-mediated nutrient recycling in western Lake Erie is limited to modelling efforts, which lack empirical validation, and do not consider microzooplankton (< 200 μm) or nitrogen. We will evaluate the role of zooplankton-mediated nutrient cycling in supporting primary production and HAB development by measuring zooplankton nutrient recycling and then comparing it to both phytoplankton nutrient demand as well as other sources and sinks. We will also use statistical modeling to identify the potential controls (e.g., temperature, seston stoichiometry, zooplankton biomass and composition) of nutrient recycling rates and ratios by zooplankton. This work will enhance our fundamental understanding of internal nutrient cycling in western Lake Erie and provide insight into the factors governing HAB magnitude and timing. Results from our work can be used to parametrize lake models, improve HAB forecasts, and address uncertainties in HABs mitigation efforts.