In less than two decades, the longest and most severe coral bleaching occurs. The bleaching, which began in 2014 is likely to last through 2016 and will impact over a third of the world’s corals.
After events in 1998 and 2010, The US National Oceanic and Atmospheric Administration (NOAA) rang the alarm in October 2015, and frightening images emerged last week of ghostly white corals in the Maldives. The bleaching began in 2014 and is likely to kill 12,000 sq km of reefs. Researchers claim that climate change should be the main focus to tackle coral bleaching rather than debating what percentage of the Reef has been impacted. They say the issue is the environmental disaster on our doorsteps and the real issue here is what’s affecting it, or what’s caused it. After their study on the issue, the finding suggested that the effect of coral bleaching in the Coral Sea is similar to that in the Great Barrier Reef.
They surveyed as far south as the southern coral about 350 km offshore from Rockhampton that hadn’t been affected by bleaching. About 240km from Cairns nearly 80 percent of corals showed some sign of bleaching and 40 percent were fully bleached and 25 percent dead. “There’s very little direct human disturbance on some of these reefs and still we see quite a lot of bleaching” Dr Hugo Harrison of the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies, said. “What we really should be tackling are the big issues of climate change.”
Corals are small and soft-bodied marine organisms called polyps that live in spectacular colonies. These colonies are called reefs that they build using a limestone skeleton (calicle) lying at their base. A polyp — which may live for 2 to several hundreds of years — starts building a reef by fixing itself to a sea-floor rock, and then budding into innumerable clones that fuse into each other to create a colony that acts as one organism. The colonies grow over thousands of years, and fuse into other colonies to become reefs. Some of today’s coral reefs started growing over 50 million years ago. Corals themselves are translucent animals related to sea anemones and jellyfish, but the reefs host zooxanthellae algae, which give them a range of dazzling colours. The algae have a symbiotic relationship with the polyps, capturing sunlight and carbon dioxide to make sugars that feed the polyps. The corals also feed on zooplankton and small fish.