The crown of thorns puts corals to the end. Credit: Katharina Fabricius, Australian Institute of Marine Science
Reading storms, too high water temperatures and a predatory starfish have severely damaged the Earth's largest coral reef: Since 1985, about half of the coral population has disappeared in the Great Barrier Reef off the north coast of Australia, now has a team of marine biologists around Glenn De? Ath from the Australian Institute of Marine Science discovered in Townsville. In the past 27 years, the reef has suffered so much that the regenerative power of the corals was overwhelmed. According to the investigations, 48 ​​percent of the damage was caused by tropical cyclones, which have accumulated in the region in recent years. Presumably, this increase is a consequence of climate change, as is the increase in average water temperature. The heat damages the cnidarians and causes the coral branches to fade. This damage accounts for about 10 percent of the total decline, say the scientists. The remaining 42 percent of the losses go back to the explosion of the so-called crowns of thorns. This starfish feeds on cnidarians and leaves dead coral branches.

Storms and rising water temperatures are the researchers largely powerless. To strengthen the reef again or stop the decline, they want to start the lever on the starfish. There are already indications that a poor water quality favors the reproduction of the greedy animals. Further studies will now investigate the possibilities of limiting the spread of the crowns of thorns. If this problem disappeared, the reef would have more time to adapt slowly to the new environmental conditions, the researchers say. So could recover parts of the coral reef, hope Glenn De? Ath and his colleagues.

Glenn De Ath (Australian Institute of Marine Science in Townsville) et al .: PNAS, doi: 10.1073 / pnas.1208909109 © science.de? Martin Vieweg

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