Empirical relationships between profundal macroinvertebrate biomass and environmental variables in boreal lakes of Alberta, Canada

1. We empirically modelled profundal macroinvertebrate biomass (PMB) from c ollections of macroinvertebrates and a suite of trophic, water chemistry an d morphometric variables from 26 lakes located within the Boreal Mixedwood and Boreal Subarctic ecoregions of Alberta, Canada. 2. Hypolimnetic dissolved oxygen (DO) concentrations (mg L-1) explained 37% of the variance in PMB ((g m(-2))(0.1)) as a quadratic function, whereas w ater temperature (degrees C) explained 23% of variance in a linear relation ship. 3. Ln contrast with other studies based on oligotrophic systems, indirect i ndicators of food availability (i.e. chlorophyll a and total phosphorus con centrations and Secchi depth) were not significant predictors of PMB in thi s study. 4. The predictive power of our models may be improved by obtaining more fre quent (seasonal) estimates of PMB and hypolimnetic DO concentration and by quantifying biotic factors such as competition, predation, life history phe nologies and recruitment success.