PARENT SESSION
Oral Session #27: Aquatic Ecology: Lake structure and function. Presiding: L.A. Hansson.
Tuesday, August 7, 2001. 8:00 AM to 11:30 AM. Hall of Ideas I.
Climate warming-induced changes in the structure and function of benthic communities in a boreal lake.
Baulch, Helen1, Schindler, David1, Turner, Michael2, Findlay, David2, Vinebrooke, Rolf3, 1 2 3
ABSTRACT- Although recent studies have shown that benthic communities provide much of the energy required for fish production in lakes, the effects of climate warming on epilithon (biofilm assemblages on rock surfaces) have received little study. Using an electronically-controlled propane heating system, we experimentally raised the water temperature in 800-L littoral enclosures to assess how an increase in water temperature of 4.5°C would affect the benthic community of Lake 239, Experimental Lakes Area, during an 8-wk period in late summer. Net photosynthesis increased by 50%, and respiration rates sometimes doubled. Algal biomass increased nearly four-fold on newly colonized tiles in warmed enclosures. Cyanophytes, chlorophytes and diatoms increased in abundance. The changes in community composition and biomass depended on the stage of community development. We will analyse long-term epilithon data in the boreal study lake to confirm the results of warming experiments.
KEY WORDS: climate, epilithon, boreal, temperature