Floating tubes test sea-life sensitivity

摘要

Global warming is not the only worrying consequence of rising carbon emissions. As levels of carbon dioxide increase in the atmosphere, more of the gas dissolves into the oceans, making the water more acidic. Marine scientists fear that the conditions will disrupt ecosystems by, for example, inhibiting some organisms' ability to build shells. Yet the effects are unclear: in small-scale laboratory tests, certain species have proved surprisingly resilient, and some even flourish. Marine biologist Ulf Riebesell says that these results tell only part of the story: scientists need to scale up and examine whole ecosystems. Lab studies of isolated species ignore variables such as competition, predation and disease, he says. Even minor effects of acidification on the fitness of individual species - especially small photosynthetic organisms such as phytoplank-ton - can upset food chains, eventually harming larger species. "If you only focus on the lab results, you are being misled," he says.