Diving into the Caribbean's Coral Science

During a boat trip with his stepfather in 1995 when he was in his early 20's, Karl Castillo, saw first-hand the effects coral bleaching had had on the magnificent Mesoamerican Barrier Reef off the coast of southern Belize.

Where there should have been healthy colourful coral gardens, instead lay bleached marine creatures which were slowly starving to death.

Determined to find out why this was happening to the world's second largest barrier reef and popular scuba diving holidays destination, Castillo returned 15 years later with colleagues as a postdoctoral researcher from UNC Chapel Hill.

"To me, this is hugely important. I grew up living right next to the ocean and seeing not only how much I enjoyed it, but how important it is," Castillo explained. "So I tried to dedicate my entire career to seeing if I could assess the different things we see happening to the ocean."

Image thanks to actaacta and Flickr

The source of the coral bleaching was a mass of warm seawater which moved in from offshore, killing the algae that provides coral with its colour and vital nutrients.

By measuring the growth of coral up to 100 years old, the journal PLoS One suggests that the creatures furthest from shore are more sensitive to environmental threats than shoreside creatures.

Justin Ries, an assistant professor of marine science and co-author of the study, said: "One hundred years ago, they had one of the highest rates of extension. Now it's the lowest. It's not like it's always been low and they just got hit harder."

Castillo is hoping that these findings will help scientists understand factors such as climate change, pollution caused by fishing boats and charter boats which bring tourists on scuba diving holidays, and the distress of coral in different areas of the reef, so that conservation groups can find ways to protect it.

Image thanks to richard ling and Flickr

Castillo added: "If they find what we're seeing is true, I think the important thing is we can make recommendations to marine protected area managers.

"They have limited resources, so they can allocate their available resources to maybe more rangers out there to minimize additional stresses on forereef coral."

The Mesoamerican Barrier Reef is the western hemisphere's largest coral reef which stretches 1000 km from Isla Contoy on the Yucatán Peninsula down to the Bay Islands of Honduras.

The reef is a playground for professional divers and tourists taking scuba diving holidays in the Caribbean, with an array of spectacular diving sites and beautiful marine species including sea turtles, whale sharks, manatees, Morelet's crocodiles, American crocodiles, Splendid Toadfish, black coral, stony coral and over 500 species of fish.

The reef features many protected areas and parks which allow limited access to tourists taking holidays for scuba diving, and both recreational and professional scuba divers, in order to allow the coral and the marine environment to replenish.