Marine animal behaviour in a high CO2 ocean

Abstract

Recently, the effects of ocean acidification (OA) on marine animal behaviour have garnered considerable attention, as they can impact biological interactions and, in turn, eco system structure and functioning. We reviewed current published literature on OA and marine behaviour and synthesize current understanding of how a high CO 2 ocean may impact animal behaviour, elucidate critical unknowns, and provide suggestions for future research. Although studies have focused equally on vertebrates and invertebrates, vertebrate studies have primarily focused on coral reef fishes, in contrast to the broader diversity of invertebrate taxa studied. A quantitative synthesis of the direction and magnitude of change in behaviours from current conditions under OA scenarios suggests primarily negative impacts that vary depending on species, ecosystem, and behaviour. The interactive effects of co-occurring environmental parameters with increasing CO 2 elicit effects different from those observed under elevated CO 2 alone. Although 12% of studies have incorporated multiple factors, only one study has examined the effects of carbonate system variability on the behaviour of a marine animal. Altered GABA A receptor functioning under elevated CO 2 appears responsible for many behavioural responses; however, this mechanism is unlikely to be universal. We recommend a new focus on determining the effects of elevated CO 2 on marine animal behaviour in the context of multiple environmental drivers and future carbonate system variability, and the mechanisms governing the association between acid-base regulation and GABA A receptor functioning. This knowledge could explain observed species-specificity in behavioural responses to OA and lend to a unifying theory of OA effects on marine animal behaviour.

Ocean acidification alters the response of intertidal snails to a key sea star predator

“…Regardless, because submerged snails remain within the sea stars' preferred habitat and can likely be sensed more readily by them, such declines in the time of emergence could translate into an increased risk of predation. It also appears that periodic rebounds of pH to higher values lasting 18 h each day neither mitigate the initiation of behavioural impairment nor enable recovery of viable escape responses once the impairment has been established (see also [42]). To the extent that T. funebralis serves as a representative model for other intertidal gastropods that react to Pisaster as a generalist predator, these findings imply the potential for disruption of a substantial number of consumptive and non-consumptive links within the food web.…”

Extreme ocean acidification reduces the susceptibility of eastern oyster shells to a polydorid parasite

“…). This can result in an array of impacts to many marine organisms, including behavioural (Briffa, de la Haye & Munday ; Clements & Hunt ) and physiological (e.g. Pörtner ) effects.…”

Juvenile Antarctic rockcod,Trematomus bernacchii, are physiologically robust to CO2–acidified seawater

“…Several studies have shown that the early developmental stages of fishes are indeed vulnerable to elevated P CO2 including changes in metabolism and swimming duration (Pimentel et al, 2014a), swimming speed (Bignami et al, 2013), sensory perception and behavior (see reviews by Munday et al, 2012;Clements and Hunt, 2015), morphological deformations (Chambers et al, 2014;Pimentel et al, 2014b;Mu et al, 2015), and survival and growth (Kikkawa et al, 2003;Baumann et al, 2011;Frommel et al, 2011Frommel et al, , 2014. Other studies have shown that the early stages of fishes are relatively robust, remaining unaffected by elevated P CO2 (Hurst et al, 2012;Frommel et al, 2013), suggesting that sensitivity to OA is both species and life-stage specific.…”