As the oceans acidify, marine invertebrates will experience physiological and behavioural changes that may alter how predators interact with their prey. This study assessed whether ocean acidification alters the predatory whelk Tenguella marginalba, their prey, the Pacific oyster, Crassostrea gigas, and their interactions. Oysters and whelks were exposed separately to ambient or elevated pCO2 for 6 weeks, after which, a reciprocal cross design was used to expose oysters and whelks together to ambient and elevated pCO2. Both T. marginalba and C. gigas were measured for growth, shell morphology, shell compression strength and metabolic rate. The rate at which whelks consumed oysters was also measured. We found C. gigas had weaker shells and greater SMR at elevated pCO2, but lowered its SMR when held at ambient pCO2 with T. marginalba. T. marginalba had a greater SMR and consumed more C. gigas when both the predator and prey were held at elevated pCO2. We also tested whether C. gigas responses to predator chemical cues were altered by ocean acidification. C. gigas lowered its metabolic rate in response to predator cues at ambient, but not elevated pCO2. We conclude that elevated pCO2 may increase the energy requirements of predators, as they attempt to maintain homoeostasis. Furthermore, elevated pCO2 may also alter the morphology and increase the visibility of prey. Whether the consequence of this will be a sustained increase in consumption by the predator is less certain as molluscs acclimate and the dynamics of other organisms in marine ecosystems are also altered.
Wright J. M., Parker L. M., O’Connor W. A., Scanes E. & Ross P. M., 2018. Ocean acidification affects both the predator and prey to alter interactions between the oyster Crassostrea gigas (Thunberg, 1793) and the whelk Tenguella marginalba (Blainville, 1832). Marine Biology 165: 46. doi:10.1007/s00227-018-3302-6. Article (subscription required).