Community Respiration Rates in McMurdo Dry Valleys Lakes: Quantifying the Activity of the Electron Transport System (ETS)

An important part of the McMurdo Long Term Ecological Research (LTER) is
monitoring of spatial and temporal patterns, and processes that control net primary production
(carbon dynamics) in perennial ice-covered lakes. One of the primary losses of carbon fixed by
phytoplankton is through respiration, directly by the phytoplankton themselves and secondarily
through the metabolic contributions of heterotrophic organisms such as bacterioplankton and
protozoa. The coupling of low metabolic activity and supersaturated gases in the water column
prohibits a direct measurement of respiration. Therefore, we measure the respiratory electron
transport system (ETS) activity which drives oxidative phosphorylation, and hence oxygen
consumption in all aerobic organisms (Packard 1985). This data set addresses this core area of
research and estimates a community-wide respiration rate at specific depths in McMurdo Dry
Valley lakes.