By Diego Arguedas Ortiz

Puerto Vargas is known for the shrinking of its once long beach, as a result of erosion. The coast has lost dozens of metres in a matter of a few years, which has had an effect on tourists and on the nesting of sea turtles that used to come to lay their eggs.

Just as the beaches have been affected, there have been effects under water, in this area of the eastern province of Limón, which runs along the the country’s Caribbean coast from north to south.

“The impact of the rise in sea level and changes in temperatures also affect the coral ecosystems,” Patricia Madrigal, Costa Rica’s vice minister of environment, told IPS.

The waters of the Caribbean sea are particularly fertile for corals, but the warming of the waters and acidification due to climate change threaten to wipe out these ecosystems, which serve as environmental and economic drivers for coastal regions.

The most visible effect is the coral bleaching phenomenon, which is a clear symptom that corals are sick. This happens when corals experience stress and expel a photosynthetic algae, called zooxanthellae, that live in their tissues, producing oxygen in a symbiotic relationship. The algae are responsible for the colors of coral reefs, so when they are expelled, the reefs turn white, and the coral is destined to die.

According to the latest report by the Intergovernmental Panel on Climate Change, published in 2015, there is clear evidence that 80 per cent of coral reefs in the Caribbean have bleached, and 40 per cent died during a critical period in 2005.

This is a recurring phenomenon all over the world. The report projected that 75 per cent of coral reefs in the world would suffer severe bleaching by the middle of this century, if greenhouse gas emissions are not curbed.

The coral reefs in the Caribbean make up about seven per cent of the world’s total, but play a key role in the economies of many coastal communities in the region.

The conservation of coral reefs goes beyond defending biodiversity. Coral reefs provide a living to nearly one billion people, offer protection by buffering coastal communities against storms and heavy swells, and bring in billions of dollars a year from tourism and fishing.

Because of this, experts from Costa Rica and the rest of the Caribbean region are calling for a halt to activities that cause global warming, such as the use of fossil fuels, and for research into how to restore coral reefs.

However, Caribbean countries should also think about reducing pollution, said biologist Lenin Corrales, head of theTropical Agricultural Research and Higher Education Centre´s (CATIE) Environmental Modeling Laboratory.

How do you maintain the resilience of coral reefs? By not dumping sediments or agrochemicals on them. A sick coral reef is more easily going to suffer other problems,” Corrales told IPS at CATIE´s headquarters.

This argument is well-known in badly managed coastal areas: marine ecosystems suffer because of human activities on land and poor health makes them more vulnerable to other ailments.

In fact, an academic study published in 2012 showed that coral degradation along Panama’s Caribbean coast began before global warming gained momentum in the last few decades. Researchers blame deforestation and overfishing.

In terms of preparing for climate change, this means a step back: it is not possible to protect against future global warming ecosystems that the countries of the region have been undermining for decades.

The sediments as a result of deforestation or poor agricultural practices prevent the growth of corals, while overfishing affects certain species key to controlling algae that infest the reefs.

IMAGES:

Cahuita National Park, on Costa Rica’s eastern Caribbean coast, is suffering a process of coastal erosion which is shrinking its beaches, while the coral reefs underwater are also feeling the impact of climate change. Credit: Diego Arguedas/IPS

A reef in an underwater mountain area in Coiba National Park, Panama. Credit: Smithsonian Tropical Research Institute

SOURCE: http://www.ipsnews.net/2017/04/climate-impact-on-caribbean-coral-reefs-may-be-mitigated-if/