CS35 Trophic Dynamics
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
FieldAL, Michigan State University, East Lansing, USA, fieldama@msu.edu
Ostrom, N, E, Michigan State University, East Lansing, USA, ostromn@msu.edu
Ostrom, P, H, Michigan State University, East Lansing, USA, ostrom@msu.edu
Russ, M, E, Michigan State University, East Lansing, USA, russmary@msu.edu
 
SEASONAL VARIATION IN THE TROPHIC STATE OF GRAND TRAVERSE BAY, LAKE MICHIGAN
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This study was conducted in Grand Traverse Bay, Lake Michigan, from April 2000 to October 2001 to assess trophic state based on the ratio of community respiration to gross photosynthesis (R/P). Values for R/P ranged from 0.91 to 1.30 in 2000 and 0.92 to 1.21 in 2001. Spring 2000 and 2001 epilimnion values were low (0.91 and 0.92 respectively), indicating a higher proportion of photosynthesis relative to respiration. In both years, R/P values were at a minimum in early summer (1.00 in July 2000, 0.92 in June 2001) and increased in late summer and fall (1.12 in October 2000, 1.15 in October 2001). The dominance of community respiration at this time must result from an external source of carbon. Given that groundwater and riverine inputs in Grand Traverse are small, we believe that sediment resuspension may provide an additional carbon source thereby enhancing respiration.