Ocean freshening adversely affects the food detection ability of the gammarid amphipod Haustorioides koreanus

초록

Anthropogenic CO2 emissions to the atmosphere have increased not only air temperature, but also precipitation, which has intensified freshening of the sea surface in some parts of the ocean. As a result, many regions, including the Yellow Sea, have been confronted with a decrease in salinity. In this study we investigated the effects of low salinity on the number of dead individuals and behaviour of Haustorioides koreanus, a gammarid amphipod living in the upper and sandy regions of the tidal flats of the west and south coasts of South Korea. The experiment was conducted over 32 days with four different salinity conditions: 30 (control), 27, 24 and 21 psu (n = 8 each). Although the number of dead individuals, the moulting frequency and burrowing and swimming behaviours of H. koreanus did not significantly differ, the time taken for food detection was increased significantly by low salinity (21 psu). A decrease in the speed of food detection suggests that low salinity can reduce the amphipod's ability to detect chemical cues.

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