Impact of ocean acidification on escape performance of the king scallop, Pecten maximus, from Norway

Abstract

The ongoing process of ocean acidification already affects marine life, and according to the concept of oxygen and capacity limitation of thermal tolerance, these effects may be intensified at the borders of the thermal tolerance window. We studied the effects of elevated CO 2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4°C (winter) or to 10°C (spring/summer) at either ambient (0.04 kPa, normocapnia) or predicted future PCO 2 levels (0.11 kPa, hypercapnia). Cold-exposed (4°C) groups revealed thermal stress exacerbated by PCO 2 indicated by a high mortality overall and its increase from 55 % under normocapnia to 90 % under hypercapnia. We therefore excluded the 4°C groups from further experimentation. Scallops at 10°C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between normocapnia-and hypercapnia-exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared with normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal's performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.

Impacts of ocean acidification on marine shelled molluscs

“…In the shelled mollusc species studied to date, most of the observations fall within the first set (Parker et al 2009(Parker et al , 2010Lannig et al 2010;Hale et al 2011;Lischka et al 2011;Schalkhausser et al 2012), in line with the hypothesis that CO 2 causes a narrowing of thermal windows (Pörtner and Farrell 2008). These observations have ecosystem implications.…”

“…As a general principle, the thermal windows of marine ectotherms, which shape their range of biographical distribution, are likely to narrow under ocean acidification (Pörtner and Farrell 2008). Nevertheless, it has to be stressed that the majority of the experiments showed that pH within the range projected for the century has no effect on respiration rates of shelled molluscs (Lannig et al 2010;FernandezReiriz et al 2012;Liu and He 2012;Schalkhausser et al 2012).…”

Intertidal oysters reach their physiological limit in a future high-CO2 world

“…Further, a decrease of pH e in response to ocean acidification in marine invertebrates is also a well-reported phenomenon (e.g. Lannig et al, 2010;Parker et al, 2013;Schalkhausser et al, 2013). In this study, the pH e of oysters dropped approximately 0.2 units when they were kept subtidally and under elevated P CO2 .…”

Will jumping snails prevail? Influence of near-future CO2, temperature and hypoxia on respiratory performance in the tropical conchGibberulus gibberulus gibbosus

“…While ocean acidification appears to have varying and in some cases no effect on metabolism (Bibby et al, 2007;Marchant et al, 2010;Melatunan et al, 2011;Wood et al, 2011;Catarino et al, 2012;McElroy et al, 2012;Manríquez et al, 2013;Matoo et al, 2013;Schalkhausser et al, 2013Schalkhausser et al, , 2014Zhang et al, 2014), a range of other important effects in molluscs, both physiological (reviewed by Parker et al, 2013;Kroeker et al, 2014) and behavioural (e.g. Vargas et al, 2013;Spady et al, 2014;Watson et al, 2014), have been described.…”