Temperature and Antarctic plankton community respiration

Antarctic plankton community respiration rates were determined from in vitro changes in dissolved oxygen. Oxygen consumption rates, measured at in situ temperatures between 0 and 6°C, were found to lie in the range 0.3-3.7 μmol O2 l-1 per 24 h. Water samples were collected between East Falkland Island and South Georgia, South Atlantic Ocean, and incubated shipboard in the dark at up to 36 temperatures between -2 and 14-C. A respiration rate at each temperature was then determined and used to calculate the temperature coefficient (Q10) of Antarctic planktonic community respiration from the Arrhenius equation. Fourteen Q0 values lay in the range 1-3, with four further values >5. This range of temperature coefficient values for community respiration is comparable to the published range of values for plankton photosynthesis. Frequency distributions of temperature coefficients for the two processes show similar modal Q105 of 2-3. Thus, this study does not lend support to the hypothesis of a differential response of photosynthesis and community respiration to low temperature.