New paper finds ocean crustaceans not affected by CO2 levels 8 times higher than the present

A new paper published in Biogeosciences finds copepods [a crustacean] were not affected by "CO2 acidified" seawater at CO2 levels of 3300 ppm, which is more than 8 times higher than the present. According to the authors, "Following the 28-day exposure period, survival was found to be unaffected by exposure to 3300 ppm CO2" and "Together, the findings indicate that apCO2 level ≤2000 ppm (the highest CO2 level expected by the year 2300) will probably not directly affect survival in C. finmarchicus."

Why concerns over "ocean acidification" are overblown

Biogeosciences, 10, 7481-7491, 2013 www.biogeosciences.net/10/7481/2013/ doi:10.5194/bg-10-7481-2013

Medium-term exposure of the North Atlantic copepod Calanus finmarchicus (Gunnerus, 1770) to CO₂-acidified seawater: effects on survival and development
S. A. Pedersen¹, B. H. Hansen², D. Altin³, and A. J. Olsen^1
1Norwegian University of Science and Technology (NTNU), Dept. of Biology, Høgskoleringen 5, 7491 Trondheim, Norway
²SINTEF Materials and Chemistry, Marine Environmental Technology, Brattørkaia 17C, 7010 Trondheim, Norway
³BioTrix, 7022 Trondheim, Norway
Abstract. The impact of medium-term exposure to CO₂-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed experimental system, fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO₂) or one of three different levels of CO₂-induced acidification (3300, 7300, 9700 ppm CO₂). Following the 28-day exposure period, survival was found to be unaffected by exposure to 3300 ppm CO₂, but significantly reduced at 7300 and 9700 ppm CO₂. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO₂-induced retardation of the rate of ontogenetic development. Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO₂ and reduced size in stage III copepodites exposed to 7300 ppm CO₂. Together, the findings indicate that apCO₂ level ≤2000 ppm (the highest CO₂ level expected by the year 2300) will probably not directly affect survival in C. finmarchicus. Longer term experiments at more moderate CO₂ levels are, however, necessary before the possibility that growth and development may be affected below 2000 ppm CO₂ can be ruled out.