How does rising atmospheric CO2 affect marine organisms?

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A Climate-Change-Induced Phenological Mismatch in a Wild Bird
Reed, T.E., Grotan, V., Jenouvrier, S., Saether, B.-E and Visser, M.E. 2013. Population growth in a wild bird is buffered against phonological mismatch. Science 340: 488-491.

The authors write that "broad-scale environmental changes are altering patterns of natural selection in the wild" and that "given a heritable basis to trait variation, evolutionary responses may ensue (Falconer and Mackay, 1996)." However, they say "a major concern is that the rate of environmental change might outstrip the pace of evolutionary adaptation, thereby threatening the persistence of [both] populations and species," citing the work of Visser (2008) and Chevin et al. (2010).

What was done
The five researchers studied a wild population of great tits (Parus major) in the Netherlands in relation to the phenology of their food supply, noting that "great tits rely on caterpillars to feed their chicks and strive to match their breeding time with the pronounced seasonal peak in caterpillar biomass, which enhances offspring survival." And this they painstakingly did "using almost four decades of individual-level life-history data from a great tit population."

What was learned
In this particular population, Reed et al. report that warmer springs had indeed "generated a mismatch between the annual breeding time and the seasonal food peak, intensifying directional selection for earlier laying dates." However, they found that inter-annual variation in population mismatch had not affected population growth, because of the fact that they "demonstrated a mechanism contributing to this uncoupling, whereby fitness losses associated with mismatch are counteracted by fitness gains due to relaxed competition."

What it means
The team of Dutch, French, Norwegian and U.S. scientists thus contends that their findings imply that "natural populations may be able to tolerate considerable maladaptation driven by shifting climatic conditions without undergoing immediate declines."

Chevin, L.M., Lande, R. and Mace, G.M. 2008. Adaptation, plasticity, and extinction in a changing environment: towards a predictive theory. PLoS Biology 8: 10.1371/journal.pbio.1000357.

Falconer, D.S. and Mackay, T.F.C. 1996. Introduction to Quantitative Genetics. Longmans Green, Harlow, Essex, United Kingdom.

Visser, M.E. 2008. Keeping up with a warming world; assessing the rate of adaptation to climate change. Proceedings of the Royal Society B: Biological Sciences 275: 649.

Reviewed XX August 2013