How does rising atmospheric CO2 affect marine organisms?

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Trees, Caterpillars, Birds and Climate
Bauer, Z., Trnka, M., Bauerova, J., Mozny, M., Stepanek, P., Bartosova, L. and Zalud, Z. 2010. Changing climate and the phenological response of great tit and collared flycatcher populations in floodplain forest ecosystems in Central Europe. International Journal of Biometeorology 54: 99-111.

A reasonable concern about potential global warming is that various links of certain food chains may not respond in a compatible manner in terms of the temporal development of the different stages of their life cycles, leading to a serious mismatch among the unique needs of different ecosystem trophic levels that could well spell disaster for some species, which concept has been said by Visser and Both (2005) to constitute an "insufficient adjustment" to climate change. So does this phenomenon, or does it not, actually occur in the real-world of nature?

What was done
In a study designed to answer this question for certain elements of an important ecosystem of Central Europe, the authors studied the responses to 47 years of warming (1961-2007) of (1) the time of leafing-out of dominant English Oak (Quercus robur) trees at four different research sites in the Czech Republic that are located in full-grown, multi-aged floodplain forests that had been under no forestry management, (2) the time of appearance of the two most abundant species of caterpillars in the floodplain forests -- the Winter Moth (Operophtera brumata) and the Tortrix Moth (Tortrix viridana) -- and (3) the first and mean laying dates of two of the ecosystem's most common birds: Great Tits (Parus major) and Collared Flycatchers (Ficedula albicollis).

What was learned
Bauer et al. report that "mean annual temperature showed a significant increase of 0.27-0.33C per decade, with approximately the same magnitude of change during spring at all sites." They also found that "on average (all four sites), the bud burst date for English Oak has advanced by 7.9 days and full foliage by 8.9 days, with approximately the same shifts being recorded for the peak of the beginning and end of frass for herbivorous caterpillars," which was the observational variable they used to characterize the caterpillars' presence. Last of all, they determined that "the first laying date of Great Tits has advanced by between 6.2 to 8.0 days," while "the mean laying date has advanced by 6.4 to 8.0 days." Likewise, they found that the "Collared Flycatcher first laying date has advanced by 8.5 to 9.2 days over the past 47 years, and the mean laying date by 7.7 to 9.6 days."

What it means
Because, as the seven scientists describe it, "trends in the timing of reproduction processes of both bird species are coherent with the trends in development of English Oak and with peak herbivorous caterpillar activity," it is readily apparent that in this specific food chain the common shifting of the different organisms' phenological stages toward the beginning of the year "does not appear to have led to mistiming in the trophic food chain." Hence, there is reason to believe that other food chains may also not be as seriously disrupted by global warming as many have postulated they could be. Obviously, however, much more work of this nature is needed before any generalities are warranted.

Visser, M.E. and Both, C. 2005. Shifts in phenology due to global climate change: the need for yardstick. Proceedings of the Royal Society B 272: 2561-2569.

Reviewed 7 April 2010