David Prichett, Rochester Institute of Technology

Class Year:

Mentor:

Abstract:

Rates of ecosystem metabolic properties, such as plankton community respiration, can be used as an assessment of the eutrophication state of a waterbody. However, given the additional labor involved in measuring biogeochemical rate processes, few monitoring programs regularly measure these properties and thus few long-term monitoring records of plankton metabolism exist. Here, we communicate the results of an analysis of nine years of biweekly plankton community respiration rates made as part of the monitoring program at the Chesapeake Biological Laboratory, situated in the lower Patuxent River estuary, a tributary of Chesapeake Bay. We found that particulate nutrients (carbon, phosphorous, and nitrogen) were the most highly correlated co-variates with respiration rate, and both statistical and kinetic models including variables for season, water temperature, and particulate nitrogen were able to explain 74% of the variability in respiration rate. We also found that both particulate nutrients and respiration rate were enhanced when tide height was higher compared to lower. Follow-up measurements of respiration rate over ten consecutive days and during high and low tide on three separate days also support the enhancement of respiration with high tide. It is possible that this could be due to the influence of the Chesapeake Bay by bringing particulate nutrients from the highly productive mid-bay. This analysis of a long-term record of metabolic rates has implications for how we interpret long-term records of measurements made at fixed locations in estuaries.