Heat wave

31 October 2016 - By: Kim Birnie-Gauvin

The effects of global warming and ocean acidification on marine ectotherms: a meta-analysis

Damselfish swim in shallow water in Palau's lagoon. Photo: Ethan Daniels

Lefevre, S. (2016). Are global warming and ocean acidification conspiring against marine ectotherms? A meta-analysis of the respiratory effects of elevated temperature, high CO2 and their interaction. Conservation Physiology 4: cow009. doi:10.1093/conphys/cow009

Climate change has been at the core of science for the past few decades. The predicted global increase in temperature will also be accompanied by ocean acidification. Research on the subject has largely focused on aerobic scope which is linked to whole-animal performance (including growth, reproduction and overall fitness). In addition, special attention has been given to marine ectotherms as they do not regulate their body temperature, but we still lack a unifying pattern to predict the effects that elevated temperature and high CO2 will have on these organisms. A newly published paper by Sjannie Lefevre (University of Oslo) presents a meta-analysis on the topic, which included 395 data sets on a variety of species, revealing that we still lack an overall correlation between resting metabolic rate (MO2rest) and temperature or CO2 regime. In 18 out of 125 data sets, CO2 caused a significant rise in MO2rest, though a decrease in MO2rest was observed in 25 of the 125 analysed data sets. An important aspect of global climate change often discussed in studies on the subject is the potential synergistic effects that temperature and CO2 may have on physiological mechanisms. However, Lefevre’s meta-analysis showed that when CO2 had an effect, additive interactions were most common, with several antagonistic interactions on MO2rest and absolute aerobic scope. The important take home message from this meta-analysis is the variation in responses to elevated temperature and CO2, and the lack of a unifying pattern to predict the impacts of global warming and ocean acidification on marine ectotherms.

Kim Birnie-Gauvin, 
MSc student, Carleton University

Category: Animal Biology