One of the most destructive effects of global climate change is the increased carbon sequestering and consequential acidification of our world’s oceans. The impacts of ocean acidification on marine organisms are still relatively unknown, especially effects on behavioral ecology. Avoiding predation has emerged from recent behavioral ecology literature as a critical feature in the life history of a wide array of animal species; experiments on marine fishes suggest acidic water compromises their predator-avoidance abilities. Recent assays in our lab suggest predator-induced behavior is reduced by weakly acidic water. These experiments do not address the potential factor of generalized malaise caused by acidic water. To test this malaise hypothesis, I examined whether predator-induced reduction in feeding, previously documented by the Wright lab, is eliminated by acidic water using the following treatments: ambient artificial seawater (ASW) acidic ASW ambient predator-scented ASW acidic predator-scented ASW
The malaise hypothesis predicts predator odor in acidic water would decrease feeding furthermore because the acidic water would sicken the subject. By contrast, if acidic water has a more subtle effect on hermit crab’s ability to detect its predator, the hermit crabs’ feeding in the presence of acidified water and predator odor should increase feeding rates to be comparable to ambient predator-free water. Preliminary experiments confirm slightly acidic water compromises predator detection, resulting in significantly more food consumption; these results discredit the generalized malaise hypothesis. This trend indicates global climate change could have significant and previously unanticipated impacts on predator-prey relations in marine communities
