Effects of low salinity and low pH on behavioral aspects of Antarctic amphipod, Gondogeneia antarctica

초록

The Gglacier located in Marian Cove, King George Island, is collapsing rapidly due to climate change, and the meltwater intrusion to the cove induces declining trends of mean salinity and pH. Following the seawater dilution and acidification, inevitable changes of the marine ecosystem near the glacier are expected. Gondogeneia antarctica, one of the abundant gammarid amphipod species in western Antarctic Peninsula, occupies important ecological niche in the cove. To predict the effects of the low salinity and pH on the population, we performed manipulation experiments for 40 days, raising G. antarctica in 4 different treatments combining two salinity (30 and 27 psu) and two pH (pH 8.0 and 7.6) levels. Low salinity increased cannibalism rates, while low pH influenced mortality except cannibalism. Foraging behavior rates was significantly reduced in the low pH levels. Meanwhile, swimming behavior during the nighttime was significantly lower in low salinity treatments. Low salinity and pH respectively decreased shelter utilization rates during the daytime, which indicates abnormal condition. Although the combined effects of low salinity and low pH were not observed during the experiments, the results suggest that each stressor due to glacier melting induces amphipods’ abnormal behavior and eventually may reduce survival in the cove.