Factors influencing seasonal changes in the respiration of Drepanopus bispinosus (Copepoda:Calanoida) in Burton Lake, a marine derived saline lake in the Vestfold Hills, Antarctica

Abstract

Oxygen consumption of adult females of Drepanopus bispinosus living in a marine derived saline lake in East Antarctica was measured under different conditions of temperature, salinity, dissolved oxygen and food concentration both in winter and summer. Variations in respiration paralleled temperature changes, particularly when the animals were in temperatures higher than in the normal habitat (0±2℃) and below the upper thermal limit (13.1℃). The Q_ values for respiration lay between 1.65 to 1.89 from August to December, but increased to 3.11 and 3.32 in January. Respiration also increased when the animals were subjected to salinities either higher or lower than normal habitat conditions (37.2-39.5‰). Oxygen consumption appeared to be related to the dissolved oxygen content and to some extent to the concentration of phytoplankton cells in the medium. The seasonal variation in respiration of adult females D. bispinosus revealed a tendency to decrease continually from August to January. This might have resulted from their reproductive activities during the period of their reproduction. Food concentration, as well as dissolved oxygen, were possible environmental factors influencing oxygen consumption. After that, it could have been mainly related to decline of their physiological functions resulting from senescence.