How does rising atmospheric CO2 affect marine organisms?

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How Does a Nondescript Shrimp Deal with Rising Temperatures?
Ravaux, J., Leger, N., Rabet, N., Morini, M., Zbinden, M., Thatje, S. and Shillito, B. 2012. Adaptation to thermally variable environments: capacity for acclimation of thermal limit and heat shock response in the shrimp Palaemonetes varians. Journal of Comparative Physiology B 182: 899-907.

The authors indicate that "all organisms possess some capacity to modify their behavioral, physiological or morphological characteristics in response to changes in environmental temperature" via a phenomenon they characterize as thermal acclimation, citing Angilletta (2009), which special case of phenotypic plasticity would obviously be of great significance to all organisms in a warming world.

What was done
Working with Palaemonetes varians, a shallow-water brackish shrimp that is native to Western Europe, Ravaux et al. assessed, via analyses conducted with both cold- and warm-acclimated specimens collected from the Bay of Mont Saint-Michel (France), the plasticity of a common index of thermal tolerance, the critical thermal maximum (CTmax), as well as the plasticity of a widespread and conserved molecular response to stress, known simply as heat shock response (HSR).

What was learned
The seven scientists determined that P. varians "shows genuine acclimation capacities" due to the plasticity inherent in both the organism's thermal limit (CTmax) and its heat shock response (hsp70 induction temperature).

What it means
In the words of Ravaux et al., P. varians "is readily able to expand its thermal range since it can shift its thermal maximum to higher temperatures and also mobilize the HSR over a wide range of temperatures above those experienced in nature." And they thus conclude that the shrimp "is potentially capable of expanding its upper thermal range," which suggests it may not even need to migrate towards cooler regions in a potentially warming world of the future in order to live the type of life to which it has long been accustomed.

Angilletta, M.J. 2009. Thermal Adaptation. Oxford University Press, Oxford, United Kingdom.

Reviewed 20 March 2013