PARENT SESSION
Poster Session 32: Biogeochemistry
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Carbon, Nitrogen, Phosphorus, and Silica biogeochemistry of the Kennebec estuary, mid-coast Maine.
Caron, Heather*,1, Souther, Christina1, Lichter, John1, 1 Bowdoin College, Brunswick, ME
ABSTRACT- The Kennebec estuary is an important source of freshwater and nutrient inputs into the Gulf of Maine. Various forms of carbon (C), nitrogen (N), phosphorus (P) and silica (Si) were sampled weekly from the freshwater tidal portion (i.e., the upper estuary) of the estuary throughout the ice-free season of 2004. Biogeochemical measurements showed the freshwater tidal ecosystem to be a strong seasonal sink for N and Si, but C and P concentrations were unaltered. Emergent vegetation takes in little dissolved orthophosphate from the water column. The lack of an effect on P concentrations suggests that the N and Si sinks are most likely associated with seasonal growth of expansive areas of emergent vegetation. The biogeochemical time series are consistent with this interpretation. Significant rates of denitrification were also detected in the freshwater tidal ecosystem. It appears the freshwater tidal portion of the estuary is acting as a buffer to the nearshore environment, preventing excessive N loading.
Key words: biogeochemistry, nitrogen, carbon, denitrification