Ecology: Rise of the sources

Cited research: Phil. Trans. R. Soc. B doi:10.1098/rstb.2010.0038 (2010)

Ecosystems can be said to have a 'metabolism' because their constituent organisms suck in carbon dioxide for use during photosynthesis and release CO₂ by respiration. 'Sink' ecosystems take in more CO₂ than they emit, whereas 'source' ecosystems do the opposite — and climate change is predicted to alter the balance between them.

Gabriel Yvon-Durocher at the Queen Mary University of London, Jose Montoya at the Institute of Marine Sciences in Barcelona, Spain, and their colleagues have developed a theoretical model of the effects of warming on ecosystem metabolism. They tested the model in 20 artificial pond ecosystems, some of which were warmed to simulate climate change, and found that the warmed ponds absorbed less CO₂. Using only a few parameters — the energy needed to photosynthesize or respire and the temperature increase — the team predicted future metabolic balances. In a hotter world, they report, sinks tend to become sources. E.M.