Rise of the Anemones

We’ve heard a lot about the devastating effect that ocean acidification will have on some corals, but less about the impact on other marine animals. In a study accepted for publication in Global Change Biology, scientists report that as waters grow more acidic, sea anemones may come out on top.

Scientists expect rising carbon dioxide levels to acidify oceans over the next century, decreasing the surface pH by 0.3 to 0.5. This change in water chemistry could weaken many corals, although some species may be hardy enough to withstand it.

The study authors decided to investigate the effect of acidification on sea anemones, which are related to corals. The team studied anemones at six shallow sites around North Vulcano Island, Italy. Three sites were close to vents that release carbon dioxide and were thus more acidic, while three “reference” sites were farther away and less acidic.

The abundance of sea anemones was about two to four times higher at the sites closer to the vents, the team found. The animals were also bigger at those spots. The size of each anemone’s pedal disc — the body part used to attach to a surface — averaged 27 to 31 millimeters at the more acidic sites, but only 21 to 23 millimeters at the reference sites.

The research suggests that sea anemones could flourish as carbon dioxide levels rise, “with fundamental implications to ecosystem function,” the authors write. The next step is to find out whether anemones in tropical areas will thrive under these conditions as well.Roberta Kwok | 20 June 2012

Source: Suggett, D.J. et al. 2012. Sea anemones may thrive in a high CO2 world. Global Change Biology (Accepted Article) doi: 10.1111/j.1365-2486.2012.02767.x.

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