The ecological and economic importance of coral reefs has long been recognized. Corals form part of the ecosystem that benefits more than 200 million people worldwide living in coastal areas by supporting jobs, providing fish harvests and attracting tourists. While corals are considered flowers of the sea and are admired for their exquisite beauty, coral reefs provide a natural form of defense for coastal communities from erosions and surging waves during storms.

In a new study on changing sea depths by the United States Geological Study (USGS) and published in the Biogeosciences, a journal of the European Geosciences Union, researchers reported that corals cannot keep pace with the rising sea level, reports Independent.

The study was conducted at five large coral reef sites: two in the Florida Keys, two Virgin Islands in the Caribbean and around the waters of Maui Island in Hawaii. The research showed that all the five sites had lost large amounts of coral, sand and other sea floor materials to erosion. The sea floor was found to be lower in all five areas from nine to 80 centimeters, reports Science News Line.

The sea floor is increasingly eroding in these five reef sites resulting in water depths not predicted to occur until 2100. With the rate the sea water is rising, seafloor erosion could increase water depths by two to eight times more than what has been predicted for 2100. The USGS researchers calculated that the seafloor losses around the waters of Maui amounting to 81 million cubic meters of sand, rock and other material, would be equivalent to 81 times of what would be needed to fill up the Empire State Building, or 32,000 times of an Olympic swimming pool.

The researchers warned that the coastal communities protected by the reefs are now facing increased risks from coastal erosion, storms, and tsunami. According to the researchers, coral reefs worldwide are declining due to a number of forces including rising temperature, coastal development, overfishing, pollution, coral bleaching, diseases and ocean acidification - a change in seawater chemistry due to the ocean's' absorption of large volumes of carbon dioxide from the atmosphere.