Acid and choky ocean: effects of ocean acidification and hypoxia on behavior and species interaction of marine animals

Abstract

Ocean acidification is now regarded as one of the most threatening stressors on marine ecosystems. Because high CO2 event in the seawater is often accompanied by lowly dissolved oxygen (DO), the effect of ocean acidification should be studied in relation with low oxygen. Here I show the two case studies on the effect of ocean acidification and low oxygen on marine invertebrates: 1. Deep-sea hermit crabs and 2. Interaction between clams and crabs. First, low pH and low DO deteriorates the olfactory behavior of deep-sea hermit crabs (Pagurus tanneri) but increases the individual variation. It suggests that deep-sea acidification could impact hermit crabs but the population may able to adapt to future acidification. Second, to determine if low pH and low DO events influence the interaction between manila clams (Venerupis philippinarum) and yellow shore crabs (Hemigrapsus oregonensis), a series of experiments were conducted. Only low pH and low DO decreased burrowing behavior of manila clams and thus increased the consumption rate of shore crabs, suggesting that there is a synergistic effect between CO2 and oxygen. Given all results, marine invertebrates could be differently influenced by ocean acidification depending on species, and high CO2, combining with low DO conditions, can influence some of marine species and eventually change marine ecosystems.ed in relation with low oxygen. Here I show the two case studies on the effect of ocean acidification and low oxygen on marine invertebrates: 1. Deep-sea hermit crabs and 2. Interaction between clams and crabs. First, low pH and low DO deteriorates the olfactory behavior of deep-sea hermit crabs (Pagurus tanneri) but increases the individual variation. It suggests that deep-sea acidification could impact hermit crabs but the population may able to adapt to future acidification. Second, to determine if low pH and low DO events influence the interaction between manila clams (Venerupis philippinarum) and yellow shore crabs (Hemigrapsus oregonensis), a series of experiments were conducted. Only low pH and low DO decreased burrowing behavior of manila clams and thus increased the consumption rate of shore crabs, suggesting that there is a synergistic effect between CO2 and oxygen. Given all results, marine invertebrates could be differently influenced by ocean acidification depending on species, and high CO2, combining with low DO conditions, can influence some of marine species and eventually change marine ecosystems.