How does rising atmospheric CO2 affect marine organisms?

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Turning Up the Temperature on the Red King Crab
Stoner, A.W., Ottmar, M.L. and Copeman, L.A. 2010. Temperature effects on the molting, growth, and lipid composition of newly-settled red king crab. Journal of Experimental Marine Biology and Ecology 393: 138-147.

The authors write that "temperature is a dominant environmental factor that mediates the behavior, physiology, growth, survival, distribution, and recruitment of ectothermic animals living in temperate and high latitudes." Hence, they decided to see how the growth and survival of the red king crab (RKC: Paralithodes camtschaticus) "may be affected by warming trends expected in Alaska," since the RKC was once that state's "most economically valuable crustacean fishery."

What was done
In the words of Stoner et al., "RKC were reared using four temperature treatments ranging from 1.5 to 12°C for a period of 60 days, both individually and in low-density populations," during and at the end of which period various physiological processes and properties were measured.

What was learned
Among other things, the three researchers report that "temperature had no significant effect on survival of RKC," while noting that "there was no consistent difference in survival between individually cultured crabs and those in populations." As for growth, they found that it "was very slow at 1.5°C, and increased rapidly with temperature with both a contracted inter-molt period and small increase in growth increment." In addition, they say that "20% of the crabs held at 1.5°C never molted, while more than 90% of the crabs in 12°C reached juvenile state 4 or higher." Overall, therefore -- as they describe it -- "growth increased as an exponential function of temperature, with slightly higher growth rates observed in populations than for isolated individuals." Also of great importance, they say they found "no evidence that culturing RKC juveniles at elevated temperatures led to a decrease in condition or nutritional status."

What it means
In addition to the benefits listed above, which bode well indeed for the RKC in a possibly warmer future world, Stoner et al. conclude that the "accelerated growth" they observed in the RKC raised at the highest temperature might yet have a "positive, indirect effect on survival," in that "larger size associated with high temperature could provide for earlier refuge in size from the typical fish and invertebrate predators on RKC."

Reviewed 12 January 2011