Washington, Nov 3 : The diversity of organisms living on the world's coral reefs is seriously underestimated, a new study has revealed.

Smithsonian scientists and colleagues conducted the first DNA barcoding survey of crustaceans living on samples of dead coral taken from the Indian, Pacific and Caribbean oceans.

The results suggest that the diversity of organisms living on the world''s coral reefs is seriously underestimated.

At depths of 26 to 39 feet, the scientists collected dead coral from five different locations.

At two sites where removing coral is prohibited, the scientists collected man-made sampling devices that had been left in the water for one year.

Combined, the coral and devices had a surface area of just 6.3 square meters (20.6 square feet), yet 525 different species of crustaceans were found living on them.

"So much diversity in such a small, limited sample area shows that the diversity of crustaceans in the world's coral reefs -- and by implication the diversity of reefs overall -- is seriously under-detected and underestimated," said Nancy Knowlton, co-author of the survey.

"We found almost as many crabs in 6.3-square meters of coral as can be found in all of the seas of Europe. Compared to the results of much longer and labor-intensive surveys, we found a surprisingly large percentage of species with a fraction of the effort."

"Given the complexity and extent of the world's coral reefs, the survey covered only a very limited depth and habitat range."

"And yet we have so many more species than we ever expected," Plaisance added.

Present estimates of species diversity in reefs are 600,000 to more than 9 million species worldwide.

The research was recently published in the journal PLoS ONE. (ANI)