Thursday, September 20, 2012

Corals need better protection from climate change

The corals are often being studied by scientists because of their vital role at the bottom of marine food chain. If corals were to go extinct this would cause irreparable damage to entire marine food web, leading to decline and extinction of many marine species.

The latest comprehensive study done by scientists from Potsdam, the University of British Columbia in Canada and the Universities of Melbourne and Queensland in Australia argues that corals will find it very hard to adapt to climate change even if global warming is restricted to the increase less than two degrees Celsius.

Warmer sea temperatures will lead to more frequent and more intense coral bleaching, and if you also add increased acidity of our seas into the equation you can see why coral will find it extremely hard to survive.

The scientists have said that only if world drastically reduces the amount of greenhouse gas emissions, and under the assumption that corals can adapt at extremely rapid rates, could two thirds of their total population survive.

They also added that the threshold to protect at least half of the corals worldwide is estimated to be below 1.5 degrees Celsius of temperature increase. Given the current levels of greenhouse gas emissions, and the lack of promising climate change talks, the “good” scenario looks more like some environmental utopia than actual reality.

In order to understand the process of coral bleaching we first need to know about the special symbiotic relationship with a special type of microalgae. Thanks to these algae corals get their color and energy.

As the water is becoming warmer this symbiotic relationship between corals and microalgae gets broken, making the coral "bleach" or turn pale. Short term speaking corals can survive bleaching but if the warm water conditions continue to persist for a longer period many of corals can die.

Some scientists hope that maybe corals will be able to adapt to this thermal stress, by for instance creating symbiosis with other algae, the ones that have a higher thermal tolerance. This level of uncertainty is however a too big gamble to take because we must not forget for one second that corals perform vital services that include coastal protection, tourism and fishing.

By protecting corals we are protecting our future wellbeing.

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