Heterotrophic Glucose Assimilation in Lake Ontario

Abstract

Heterotrophic glucose uptake was measured during 1980 in Lake Ontario plankton populations. Uptake rates of glucose were generally low (0.003 – 0.457 mg C·m −3·h −1) compared with corresponding photosynthetic carbon uptake (8 – 32 mg C·m −3·h −1). Particle size fractionation studies confirmed that a majority of heterotrophic carbon uptake was in the 1 – 8 μm diameter size class. Although heterotrophic carbon utilization by algae and bacteria was small when directly compared with photosynthetic production, heterotrophy might contribute significantly to the carbon flux within a water column over a 24-hour period.