PARENT SESSION
PW13 - Trophic Transfer
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P870) The relationship between phytoplankton composition, phytoplankton nutrient status and PCBs in lake trout in 25 lakes.
Guildford, Stephanie*,1, Muir, Derek2, Kling, Hedy3, Drouillard, Ken4, Evans, Marlene5, Kidd, Karen6, Payne, Jerry7, Whittle, Mike8, Wang, Xiaowa2, 1 University of Waterloo, Waterloo, ON, Canada2 National Water Research Institute, Burlington, ON, Canada3 Algal Taxonomy and Ecolgy, Winnipeg, MB, Canada4 Universtiy of Windsor, Windsor, ON, Canada5 National Water Research Institute, Saskatoon, SK, Canada6 Freshwater Institute, Winnipeg, MB7 Fisheries and Oceans, St. Johns, NF, Canada8 Fisheries and Oceans, Burlington, ON
ABSTRACT- Phytoplankton composition, phytoplankton nutrient status and PCB concentration in lake trout was assessed in 25 lakes from Canada and the northeastern USA. The lakes provided a wide range of PCB concentrations. Lakes containing phytoplankton from the dinoflagellate and cryptomonad genera and with low particulate carbon to particulate nitrogen ratios (C:N) (a measure of phytoplankton nutrient status) were more likely to have lake trout with elevated PCB concentrations than lakes with cyanobacteria (blue-green algae) and higher C:N ratios. Many dinoflagellates are mixotrophic which could have the effect of adding another link to the food chain. Cryptophytes are found in low light environments in oligotrophic lakes and have lipid storage products. These lipid storage products may enhance the bioaccumulation of PCBs in the aquatic food web. Cyanobacteria are typical of eutrophic lakes. The low C:N ratio in lakes with higher lake trout PCB concentrations indicated that phytoplankton in these lakes were not strongly nutrient deficient and were likely light limited. The lakes with lower lake trout PCB concentrations had higher C:N ratios which is an indication that phytoplankton in these lakes are not light limited and are more likely to be nutrient limited.
Key words: Phytoplankton, Trophic Transfer, PCBs, nutrients