Indian Ocean Experiences Severe Coral Bleaching

The intense heat that comes out of our taps when you run water for the first few minutes isn't just affecting us, it's affecting corals – delicate organisms found in the sea that are exposed to the sun all day. A marine environmentalist and regular diver has noticed the early signs of coral bleaching in the East cost lately. The corals there are pale in colour and some have turned white completely. Some corals there are deep purple too and that is an early sign of bleaching. About 50%-60% of the corals that are in Pigeon Island and Coral Island are partially bleached and about 5% are completely dead. Corals are the rainforests of the sea, they are known for this because of their rich biodiversity and are the breeding grounds for many fish. Other divers have noticed that the corals in Trincomalee, Batticaloa, Galle, Unawatuna and Hikkaduwa are also being affected. Coral bleaching happens when the coral polyps which is the organism which builds corals, shed the algae that gives them their colour. These algae are very small; they live in harmony with the corals and provide the food for the host through the photosynthesis process. Without the algae, the coral looks a pale white and the coral polyps can be exposed to UV radiation. Without oxygen, food or cover from UV rays, the coral polyps in the reef will die a few weeks after they start to loose their colour. The corals in the Indian Ocean show signs of the first stage of coral bleaching. Scientists say that the warming waters are the most likely cause of the bleaching of the corals. In 1998 the Indian Ocean saw its worst coral bleaching which was due to the warm oceanic current. The Sea Surface Temperature (SST) in some parts of the Indian Ocean had risen, due to the La Nina climatic phenomenon at the time which resulted in warm oceanic currents killing coral reefs in many areas in Sri Lanka. This included Hikkaduwa which still sees the coral reef trying to recover. Recent SST data shows it is around the 32 C mark where the average normal SST should be about 28 C. This increase could have triggered the bleaching and a regional warning has been issued. If the temperature of the sea declines, or up-swells come to the rescue, healthy corals may also have the chance to recover. “It's still early days so it's hard to know whether this will form into a full-scale coral event, such as the bleaching which happened in 1998, but it's very important that the problem here is being monitored” said the marine environmentalist. The National Aquatic Resources Research and Development Agency (NARA) marine biologists have recently reported dying corals in reefs near Galle. After the severity of the 1998 bleaching, in many areas of Sri Lanka, corals showed temporary bleaching in the months of April, May and June when temperatures are high. Some of the corals die, but most recover once the water conditions return to normal. However, it could be deadly if these warm conditions prevail for long. The only way to fight this phenomenon is to keep the corals healthy. Frequent fishing, pollution from land-based sources, sedimentation and dynamiting reefs all play a big part in the threats against the ecosystems of the reefs which dramatically reduce the ability for them to withstand such catastrophe like bleaching. The latest threat to be added to the list is Ocean Acidification which is a phenomenon linked to increased atmospheric carbon dioxide. When dissolved in the water, Carbon dioxide reacts with the water and forms carbonic acid. Many underwater ecosystems like the coral reefs are adapted to a small range of pH levels and and increase in such levels can be tragic. Marine experts want to pay more attention to the corals found in the East coast. Unlike the West coast which experiences monsoons which coll the seas slightly, the East is not as fortunate and is also experiencing new threats. Pollution and over-fishing were not problems before because the Eastern and Northern seas were restricted due to security reasons. However, this is changing since the war and over-visitation is causing issues in the the fragile marine national parks such as Pigeon Island.

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