CS08 Biogeochemical Cycles
Date: Monday, June 10, 2002
Time: 11:00:00 AM
Location: Saanich
 
NowlinWH, NSERC/IRC Environmental Management of Drinking Water Lab University of Victoria Dept. of Biology, Victoria, Canada, wnowlin@uvic.ca
Davies, J, M, NSERC/IRC Environmental Management of Drinking Water Lab University of Victoria Dept. of Biology, Victoria, Canada, jmdavies@uvic.ca
Mazumder, A, , NSERC/IRC Environmental Management of Drinking Water Lab University of Victoria Dept. of Biology, Victoria, Canada, mazumder@uvic.ca
 
EFFECTS OF SEASONAL DRAWDOWN ON A DRINKING WATER RESERVOIR: RESPONSES OF PELAGIC PHOSPHORUS PATHWAYS
image
Many reservoirs experience large seasonal fluctuations in water level, a characteristic that often distinguishes reservoirs from natural lakes. Such changes have the potential to alter the physical characteristics of the pelagic environment (light and mixing), and therefore affect the biota and nutrient pathways through planktonic food webs. This study examines the effect of seasonal reservoir drawdown on a drinking water reservoir located in coastal British Columbia, Canada. The major pathways of phosphorus (P) in oligotrophic Sooke Lake Reservoir were examined and compared to a nearby oligotrophic lake of similar size and morphometry that does not experience significant seasonal water level fluctuations (Shawnigan Lake). Sooke Lake Reservoir experienced shorter periods of summer stratification and had a less stable water column than the natural lake in 2000 and 2001. The processes of phosphate uptake and regeneration by various size classes of plankton, the movement of P into the grazing food chain and loss of P via sedimentation are examined in relation to the effects of drawdown.