Physiological responses and scope for growth in a marine scavenging gastropod, Nassarius festivus (Powys, 1835), are affected by salinity and temperature but not by ocean acidification

In the past few years, there has been a dramatic increase in the number of studies revealing negative or positive effects of ocean acidification on marine organisms including corals, echinoderms, copepods, molluscs, and fish. However, scavenging gastropods have received little attention despite being major players in energy flow, removing carrion, and recycling materials in marine benthic communities. The present study investigated the physiological responses (ingestion, absorption rate and efficiency, respiration, and excretion) and scope for growth (SfG) of an intertidal scavenging gastropod, Nassarius festivus, to the combined effects of ocean acidification (pCO₂ levels: 380, 950, and 1250 µatm), salinity (10 and 30 psu), and temperature (15 and 30°C) for 31 d. Low salinity (10 psu) reduced ingestion, absorption rate, respiration, excretion, and SfG of N. festivus throughout the exposure period. Low temperature (15°C) had a similar effect on these parameters, except for SfG at the end of the exposure period (31 d). However, elevated pCO₂ levels had no effects in isolation on all physiological parameters and only weak interactions with temperature and/or salinity for excretion and SfG. In conclusion, elevated pCO₂ will not affect the energy budget of adult N. festivus at the pCO₂ level predicted to occur by the Intergovernmental Panel on Climate Change (IPCC) in the year 2300.