Why are coral reefs in the world disappearing?

In a recent study, scientists said a lot of new knowledge about coral biology has been discovered in the past few years, helping explain why coral reefs around the world gender is gradually disappearing, as well as what needs to be done so that they can overcome climate change and ocean acidification.

It seems that corals, with a complex genome equivalent to the human genome, and sophisticated biological information systems are threatened by global climate change, can only exist based on utilization. reasonable symbiotic relationships with algae living inside corals - lead recent reports by scientists in Science.

Part of the funding of the study is supported by the National Science Foundation.
'We have long known about the general functioning of corals and the problems they are facing due to climate change,' said Virginia Weis, a zoology professor from Oregon State University. 'But only recently have we learned a bit about basic biology, genetics and internal information in their bodies. Only when we really understand the physiology of corals do we know how they will adapt to climate change, or what people should do to help corals. "

Coral is a tiny animal, a polyp species that exists with identical genome individuals that can eat, defend and kill plankton as food.In the process, they also produce calcium carbonate, which forms the basis for the extended skeleton they sit on.

Over a long period of time, these calcifications will grow to a gigantic size and create coral reefs - one of the most useful ecosystems in the world, which can nourish more than 4,000 species of fish and Many other marine life forms.

But coral is not really self-sufficient. Inside the body, corals give a useful species of algae that live in symbiosis - this is a form of carbon-attracting marine plants that uses solar energy to conduct photosynthesis and produce sugar.

'Some of the algae living in this san body are strangely useful, and in some cases, they provide 95% of the sugar produced to power corals,' Weis said. 'In return, algae collect nitrogen, a very rare nutrient in the ocean. This is really a nice symbiotic relationship. '

However, what scientists are working on is this relationship based on a process of sophisticated information from algae to corals, how to tell if the algae belong to the coral and everything is fine.Otherwise, the coral will 'treat' the algae like a parasite or an intruder, and will try to kill them.

A coral cluster. (Photo: Oregon State University)

'Although corals depend on algae as a big food source, corals may not be aware of this,' Weis said . 'We believe that this is what happens when seawater warms up or when something presses on the coral - then the process of information from the algae to the coral will be broken, and the message about Useful coexistence will not be transmitted to corals, and then algae will be forced to flee or face the coral's immune response. '

This internal information process, Weis said, is not like some processes in humans and other animals. One of the findings of recent research, she said, is the enormous complexity of coral biology, and even the similarity to other life forms. For example, genes that control human bone development are identical to those that help develop extended bones in corals - this is an example to illustrate that there are common traits that remain in species across hundreds. million years since they split along different evolutionary paths from a common ancestor.

Researchers say there are still a lot of things to discover about this process and accompanying it is an extremely diverse combination.For example, there are 1,000 different species of corals, and there are probably thousands of species of algae that form different combinations of symbiosis with corals. Experts say that this diversity brings hope that there will be reasonable combinations to help corals better adapt to changing conditions of ocean temperature, acidity and other threats. .

Coral reefs are increasingly facing huge problems. They are currently pressured by changes in ocean temperatures, pollution, overfishing, sedimentation, acidification in water, oxygen stress and all kinds of diseases, and combined effects. At the same time some problems can destroy coral reefs, though coral will still live well if only facing each problem.Some estimates show that up to 20% of the world's coral reefs are dead, and an additional 24% are seriously threatened.

As predicted, the acidification of the ocean in the next century will reduce coral reefs by 50% and increase coral bone decay, leading researchers in the report.

'With new discoveries about the calcification process and the symbiotic life of corals, coral biologists are now thinking in new directions,' Weis said. 'Perhaps we can still do some things to find and protect corals that are able to survive in different environmental conditions; we will not have to stand by our arms and watch the spectacle of the Earth's coral reefs dying and disappearing completely. '

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