METABOLIC RESPONSES OF THE SYMPAGIC AMPHIPODS GAMMARUS-WILKITZKII AND ONISIMUS-GLACIALIS TO ACUTE TEMPERATURE-VARIATIONS

Acutely elevated seawater temperatures had pronounced metabolic effect on the Arctic under-ice amphipods Gammarus wilkitzkii and Onisimus glacialis, collected in May 1986 and 1988 in the Barents Sea. An increased rate of oxygen consumption vs temperature was observed for both species. In the range from 0-degree to 10-degrees-C G. wilkitzkii and O. glacialis exhibit Q10 values of 3.4 and 3.6, respectively. The results also indicate increased ammonia excretion rates for G. wilkitzkii and O. glacialis by an elevation of temperature from 0-degree to 0-degrees-C, with an overall Q10 of 1.9 and 2.3, respectively. The present study demonstrates an increased O:N ratio with ambient temperature elevation from 0-degree to 10-degrees-C for G. wilkitzkii and O. glacialis, with overall Q10 values of 2.0 and 1.6, respectively. This indicates a temperature-induced change in the metabolic substrate towards lipids.