Anthea Aikins
Delaware State University

"Analysis of Enzyme Activity and Nutrient Limitation in the Mississippi River Plume in the Gulf of Mexico and its Possible Relationship to Hypoxia."

Mentors

Hypoxia results when the amount of oxygen consumed by bacterial decomposition in an aquatic environment exceeds the amount produced by photosynthesis. External sources or biological processes, such as photosynthesis enhanced by nutrients, supply these aquatic environments with organic matter. Various research and experiments conducted over the last several decades indicates that hypoxia in the northern Gulf of Mexico is caused primarily by excess nutrients discharged from the Mississippi-Atchafalaya River Basin. I will study factors contributing to the hypoxic zone by measuring the enzyme activity of aminopeptidase and alkaline phosphatase, enzymes found on the surface of marine bacteria and phytoplankton. These enzyme activities are measured using highly sensitive fluorescent substrates. I will run assays of both filtered (mostly bacterial cells) and unfiltered (bacterial cells and other microorganisms) water samples from the Gulf, add the substrates for the enzymes, and take the initial and final fluorescence readings (after incubation) using a fluorescence microplate reader. High peptidase or phosphatase activities found in certain regions of the Mississippi River Plume or in nutrient addition experiments suggest areas of significant nitrogen or phosphorus limitation, respectively.