Additive effects of pCO2 and temperature on respiration rates of the Antarctic pteropod Limacina helicina antarctica

The Antarctic pteropod, Limacina helicina antarctica, is a dominant member of the zooplankton in the Ross Sea and supports the vast diversity of marine megafauna that designates this region as an internationally protected area. Here, we observed the response of respiration rate to abiotic stressors associated with global change – environmentally relevant temperature (-0.8˚C, 4˚C) and pH treatments reflecting current-day and future modeled extremes. Sampling repeatedly over a 14-day period in laboratory experiments and using microplate respirometry techniques, we found that the metabolic rate of juvenile pteropods increased in response to high pCO2 exposure (920 µatm) at -0.8˚C, a near-ambient temperature. Similarly, metabolic rate increased when pteropods were exposed simultaneously to multiple stressors, elevated pCO2 conditions (960 µatm) and a high temperature (+4˚C). Overall, the results showed that pCO2 and temperature interact additively to affect metabolic rates in pteropods. Fu...