Water Resources Research Act Program

Details for Project ID 2014NC186B

Quantification of Fecal Bacteria Removal by Micro-zooplankton Grazing in Stormwater BMPs

Institute: North Carolina
Year Established: 2014 Start Date: 2014-05-01 End Date: 2015-04-30
Total Federal Funds: $7,500 Total Non-Federal Funds: $77,868

Principal Investigators: Michael Mallin, Lawrence Cahoon

Abstract: A high priority for WRRI and environmental managers in general is the control of stormwater runoff pollution. Stormwater high in fecal microbes is especially problematic in coastal areas where humans can become ill from swimming in contaminated waters and eating contaminated shellfish. It is of clear value to design stormwater best management practices (BMPs) to achieve optimal removal of fecal microbial pollution from stormwater. Grazing by micro-zooplankton (rotifers and protozoans) is believed to be a major factor in fecal bacterial removal in BMPs (especially stormwater wetlands) but this impact remains unquantified. This proposed research is designed to determine if micro-zooplankton grazing is a significant loss factor, and determine if it differs between a wet detention pond and a constructed wetland, if presence of aquatic vegetation enhances grazing, and determine if the species of aquatic macrophyte makes a difference in such grazing. As such, seasonal laboratory experiments will be conducted to test the above hypotheses, using appropriate controls for loss by UV radiation and natural mortality. Both three-day bioassays testing various aquatic macrophyte species, and 24-hr dilution assays will be used to determine micro-grazing differences between BMPs, among aquatic macrophyte materials, and between seasons with the ultimate goal of providing practical information that will improve the design of future BMPs to maximize fecal bacterial removal from stormwater.