The total area of coral cover of the reef in 1985 declined by 50%, with almost half of the decline, "provided" the predatory starfish — the crown of thorns, Australian researchers wrote in a paper published in the journal Proceedings of the National Academy of Sciences.
Experts of the Australian Institute of Marine Science (AIMS) in 1985 followed the state of the cluster of coral stretches for 2.3 thousand kilometers along the northeastern coast of Australia. In total, the monitoring program, which covered more than 100 small reefs that make up the Great Barrier Reef, has invested about $ 50 million.
"Our study shows that the reef for 27 years, has lost more than half of the total area of coral cover. If the trend continues, by 2022 coral becomes even half," — said the project developer Peter Doherty (Peter Doherty), whose words are reported Institute.
According to him, the area of coral on the reef is reduced uniformly, was particularly hard hit in recent years, its southern part.
The main causes of coral mortality, according to scientists, became a tropical storm, which accounted for about 48% of the reduction in their area, as well as sea stars form a crown of thorns (Acanthaster planci), which destroyed about 42% of the area. The remaining 10% are "bleaching" of coral due to increasing temperature and increase the acidity of the water.
"Our data show that the reefs can naturally recover from shocks, but it takes about 10-20 years. Now intervals between shocks are most likely to be too short for a full recovery, and thus there is a long-term damage (to the reef)," — said study co-author in the AIMS Suetmen Hugh (Hugh Sweatman).
According to calculations of the researchers, without the threat of Thorns coral cover recovered at an average rate of about 0.89% per year, so curb the spread of this "pest", in their opinion, can contribute to solving the problem.
The World Wildlife Fund (WWF) in Australia earlier this year said that the loss of coral reef in the largest, which in total is about 10% of all the world's coral reefs in the country A delegation of UNESCO.