Scientists have warned about the continuing threat of coral bleaching
and the potential danger this is having on marine life. Photo courtesy of NOAA
Corals and coral reefs are extremely important. They provide food, shelter and a breeding ground for around 25% of marine life and support 500 million livelihoods, such as fishing and tourism. Coral Reefs also provide coastal shelter, working like offshore seawalls protecting tropical coastlines from being battered by waves. Without them, we could be facing a much darker future.
For years now, we have been seeing the effects of coral bleaching, but scientists have recently warned that this is on the rise at an alarming rate. Coral bleaching occurs when the symbiotic relationship with Zooxanthellae, a microscopic algae which lives inside the tissue of the coral, comes to an end. The Zooxanthellae feed the coral and provide their differing colours. When coral become stressed, it dispels the algae, losing its food source and colour range so it turns pale and white. When they are in this state, corals are highly susceptible to the threat of disease. Bleached coral is not actually dead, however mortality rates increase if the situation does not return to normal or if the coral isn’t strong enough to pull through. Even if corals do recover, it can take decades to get back to normal.
Coral bleaching can be caused by a variety of factors:
– Temperature change
– Pollution and run off
– Severe Low tides
– Overexposure to sunlight
– Ocean acidification also has an effect on corals and this is increasing due to the oceans absorbing our excessive CO2 emissions, which adjust the pH levels of the seawater.
The most prominent reason for coral bleaching is our rising sea temperatures, with climate change thought to be the cause of such significant impact. Scientists are warning the El Nino, a warm band of water which devlops in the Pacific, is to blame for a mass bleaching epidemic which recently occurred in the Earth’s coral reef’s. The last record breaking El Nino occurred in 1998 and bore “...more energy than a million Hiroshima bombs” (National Geographic). It caused severe flooding, increased temperatures and total devastation for some. It also caused the first global bleaching to occur. It was repeated in 2010 when, once again, temperatures soared and El Nino came with a lot of power.
Scientists are concerned this years El Nino could be even stronger; potentially the strongest in history, meaning bleaching could be at an all time high. The US National Oceanic and Atmospheric Administration (NOAA) have published a projection predicting that 38% of coral reefs around the world will be affected by coral bleaching over the next four months. That equates to 12,000 sq. km of corals dying off – a total loss of 5% of the worlds corals. Hawaii is currently experiencing high volumes of bleaching described as ‘severe’, where some of the corals have already died. After already being hit in 2014 by a bleaching epidemic, there are great concerns for corals in the water around the islands. Areas around Florida and the Caribbean have also been hit and there are growing concerns about the Great Barrier Reef as predictions have been made that bleaching will begin in Australia next year. Gregor Hodgson of Australian ReefCheck, said the future is “truly terrifying”. Since the last record breaking El Nino is 1998, our waters have risen by a worrying two-fifths of a degree and NOAA are concerned that this will continue, with next year being on par with 2015 or potentially even worse.
With increasing oceanic temperatures and changes in pH, some scientists believe that by 2050 we will have lost most, if not all, our coral species. Scientists are hoping that the next few months of bleaching will help to build a model of the coral’s future so they can begin working on damage control, if it is even possible. Predictions about the impacts of this years El Nino are beginning to be released, with reports of cyclones, 4 millions people without food and water and flooding. This surely has to be enough evidence to convince the world about the massive danger of climate change and how we need to pull together across the world to change things before they are too late.
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