Why is the world's coral reefs are disappearing

In a recent study, scientists said new knowledge about the biological life of the coral was discovered a few years ago, helps explain why the coral reefs around the world world are disappearing, as well as the need to do so that they can overcome climate change and ocean acidification.

It looks like coral, with a complex genome equivalents in the genome, and information systems biology sophisticated threatened by global climate change, can only exist based on the utilization reasonable symbiotic relationship with algae complex inside the body coral - citing a recent report by scientists in the journal Science.

Part of the funding of the study was supported by the National Science Foundation funded part.
"For a long time we have known about the general operation of the corals and the problems they are facing due to climate change," Virginia Weis, a professor of zoology from the University of Oregon said. "But only recently did we learn a little about the fundamental biology, genome and internal communication within the body. Only a true understanding of the physiology of corals, we know ourselves we will adapt to climate change, how, or what people do to help the reef. "

Corals are tiny animals, polyps species exist with individuals genetically identical, can eat, defend themselves and kill plankton for food. In the process they also secrete calcium carbonate - quality form the basis for an external skeleton on which they sit.

Over the longer period, the calcified deposits can grow to a huge size and made of coral reefs - one of the most useful ecosystems in the world, can cultivate more than 4,000 species of fish and so many other marine life forms.

But corals are not really self-sufficient. Inside the body, coral algae useful for a symbiotic - a form of marine plants have the ability to absorb carbon, using solar energy to carry out photosynthesis and produce sugar.

"A few of the algae that live within corals are amazingly productive, and in some cases, they provide 95% sugar into energy production for corals," Weis said. "In turn, the algae collected nitrogen, a limiting nutrient in the ocean. This really is a symbiotic relationship good. "

However, what the scientists are studying the relationship is based on a delicate communication process from the algae to the coral, telling it that the algae belong corals and everything nice. If not, the coral will "treat" algae as a parasite or invader and attempt to kill them.



A coral. (Photo: Oregon State University provided)
"Even though the coral depends on the algae as a major food source, corals may not know this," Weis said. "We believe this is what happens when sea water warms or something to put pressure on coral - as it processes information from the algae to the coral breaks down, and messages useful coexistence will not be transmitted to the coral, algae and then forced to flee or face the immune response of coral. "

Internal process this information, Weis said, unlike some processes in humans and other animals. One of the findings of a recent study, she said, is the enormous complexity of coral biology, and even its similarity to other life forms. For example, genes that control bone growth in the genetically identical to help develop an external skeleton of the coral - this is an illustrative example that there are common features remain in the hundreds of species million years since we separated according to the different evolutionary paths from a common ancestor.

The researchers said, there are still many things to discover about this process and comes with it is a combination of extremely diverse. For example, there are 1,000 different species of coral and perhaps thousands of species of algae all different combinations symbiotic corals. Experts said that the diversity brings hope to have a reasonable combination helps corals adapt better to the changing conditions of ocean temperature, acidity and other threats .

Coral reefs are increasingly faced with enormous problems. They are currently being pressured by changes in ocean temperatures, pollution, over-fishing, sedimentation, acidification of water, oxygen pressure and all kinds of disease, and the combined effect simultaneously by several problems that can destroy coral reefs coral although still better off if only faced each problem. Some estimates suggest that as many as 20% of the world's coral reefs have died, and another 24% of the reefs are seriously threatened.

As expected, the acidification of the oceans in the next century will reduce 50% of coral reefs and increase the dissolving of coral skeletons, the researchers quoted in the report.

"With the new discovery of calcification and the life of the coral symbiosis, the coral biologists are now accumulate thinking in new directions," Weis said. "Maybe we can do a few things to look out and protect coral species have the ability to survive in different environmental conditions; we will not just stand by as the coral reefs of the Earth gradually die and disappear completely. "


cite:Virginia M. Weis and Denis Allemand. What Determines Coral Health? Science, 2009; DOI: 10.1126/science.1172540