Reef in Bermuda.
Healthy coral reefs have declined by about 50% in the past 40 years

Many of the Caribbean's coral reefs could vanish in the next 20 years, according to a report published by the International Union for the Conservation of Nature (IUCN).

Data from more than 35,000 surveys suggests that habitats have declined by more than 50% since the 1970s.

The report's authors believe that over-fishing and disease is mainly to blame.

They say the trend could continue if nothing is done, but with protection the reefs could bounce back.

Carl Gustaf Lundin, director of IUCN's Global Marine and Polar Programme, said the findings were alarming.

"The reefs support a number of different countries and populations," he said.

"Tourism is one of the biggest industries, and the health of the reef is essential to the well-being of many of the people living there. And of course they are immensely beautiful and wonderful places as well."

Reef overrun with algae The reefs are becoming over-run with algae, which suffocates the coral.

Ocean Acidification destroying Antarctic marine life

 
The research took place in the Southern Ocean
 

Marine snails in seas around Antarctica are being

affected by ocean acidification, scientists have found.

An international team of researchers found that the snails' shells are being

corroded.

Experts says the findings are significant for predicting the future impact of

ocean acidification on marine life.

The results of the study are published in the journal Nature Geoscience.

The marine snails, called "pteropods", are an important link in the oceanic

food chain as well as a good indicator of ecosystem health.
 

"They are a major grazer of phytoplankton and... a key

prey item of a number of higher predators - larger plankton, fish, seabirds,

whales," said Dr Geraint Tarling, Head of Ocean Ecosystems at the British

Antarctic Survey (BAS) and co-author of the report.

The study was a combined project involving researchers from the BAS, the

National Oceanic and Atmospheric Administration (NOAA), the US Woods Hole

Oceanographic Institution and the University of East Anglia's school of

Environmental Sciences.

Ocean acidification is a result of burning fossil fuels: some of the