SS3.12 Large Scale Ecosystem Manipulations
Date: Thursday, June 13, 2002
Time: 4:15:00 PM
Location: Carson C
 
HarrisSL, University of British Columbia, Vancouver, Canada, sharris@eos.ubc.ca
Stockner, J, G, Eco-Logic Ltd., Vancouver, Canada, stockner@telus.net
Pieters, R, , University of British Columbia, Vancouver, Canada, roger@ocgy.ubc.ca
 
PHYTOPLANKTON PRODUCTION IN ARROW LAKES RESERVOIR, B.C. (CANADA) DURING EXPERIMENTAL FERTLIZATION.
image
The production response of phytoplankton was studied as part of a multidisciplinary fertilization experiment on Arrow Lakes, British Columbia. The goal of the experimental treatment was to reverse oligotrophication impacts of hydroelectric dams and restore stocks of kokanee, a native land-locked salmon (Oncorhynchus nerka) to historical levels. Size-fractionated chlorophyll and primary productivity and phytoplankton enumeration were the focus of the study. Phytoplankton biomass increased 2.8-fold in 2000 and 6-fold in 2001 relative to the unfertilized year (1998) and was mainly dominated by pico and nanoplankton. Nanoplankton dominated the primary productivity during the spring and summer, while in the fall the relative contribution of microplankton was the greatest. In 2000, (second year of fertilization) there were significant changes in the community composition and seasonal successional patterns of phytoplankton. The relative contribution of picoplankton, dominated by Synechococcus spp. diminished while during the late summer and fall, diatoms (Cyclotella spp., Asterionella formosa and Fragilaria spp.) dominated the phytoplankton community. Results of this study will be incorporated into a primary productivity/fish model to forecast the rearing capacity of large, interior BC lakes and reservoirs.