LONG- AND SHORT-TERM PATTERNS IN MICROBIAL EXTRACELLULAR ENZYME ACTIVITY ALONG THE MISSISSIPPI GULF COAST

Marine microorganisms play critical roles in biogeochemical cycling, largely through the activity of extracellular enzymes. While the involvement of these enzymes in organic matter degradation is well-known, how microbial enzyme activity fluctuates over different timescales is uncertain. Using artificial substrates, day-to-day, week-to-week, and month-to-month variation in the activity of phosphatase and beta-glucosidase was examined in seawater at five shoreline sites along the Mississippi Gulf Coast, and related to variability in water temperature, pH, dissolved oxygen, and salinity. Enzyme activity varied over each timescale, with phosphatase showing greater variability at scales of day-to-day and week-to-week, while beta-glucosidase showed greater variability from month-to-month. Phosphatase varied across sites over the week-to-week and month-to-month timescales, while beta-glucosidase varied by site during the day-to-day, week-to-week, and month-to-month timescales. Phosphatase activity over day-to-day and week-to-week timescales was correlated with patterns in salinity and conductivity, whereas beta-glucosidase activity was correlated with pH over day-to-day scales and with conductivity, salinity, and pH over week-to-week. Neither enzyme was correlated with environmental factors over month-to-month timescales.  These findings show how short- and long-term variability can influence enzymatic activity of the nearshore marine microbial community that could lead to impacts on biogeochemical cycling in coastal waters of the Gulf of Mexico.

Presentation Preference: Poster

Primary Presenter: Jacqueline Pavlovsky, University of Mississippi (jpavlovs@go.olemiss.edu)

Authors:

Jacqueline Pavlovsky, University of Mississippi  (jpavlovs@go.olemiss.edu)

Stephanie Vaughn, University of Mississippi  (snvaughn@olemiss.edu)

Jordan Heiman, University of Mississippi  (jaheiman@go.olemiss.edu)

Colin Jackson, University of Mississippi  (cjackson@olemiss.edu)