Physiological responses and scope for growth upon medium-term exposure to the combined effects of ocean acidification and temperature in a subtidal scavenger Nassarius conoidalis

Physiological responses (ingestion rate, absorption rate and efficiency, respiration, rate, excretion rate) and scope for growth of a subtidal scavenging gastropod Nassarius conoidalis under the combined effects of ocean acidification (pCO(2) levels: 380, 950, 1250 mu atm) and temperature (15, 30 degrees C) were investigated for 31 days. There was a significant reduction in all the physiological rates and scope for growth following short-term exposure (1-3 days) to elevated pCO(2) except absorption efficiency at 15 degrees C and 30 degrees C, and respiration rate and excretion rate at 15 degrees C. The percentage change in the physiological rates ranged from 0% to 90% at 15 degrees C and from 0% to 73% at 30 degrees C when pCO(2) was increased from 380 mu atm to 1250 mu atm The effect of pCO(2) on the physiological rates was enhanced at high temperature for ingestion, absorption, respiration and excretion. When the exposure period was extended to 31 days, the effect of pCO(2) was significant on the ingestion rate only. All the physiological rates remained unchanged when temperature increased from 24 degrees C to 30 degrees C but the rates at 15 degrees C were significantly lower, irrespective of the duration of exposure. Our data suggested that a medium-term exposure to ocean acidification has no effect on the energetics of N. conoidalis. Nevertheless, the situation may be complicated by a longer term of exposure and/or a reduction in salinity in a warming world. (C) 2015 Elsevier Ltd. All rights reserved.