World's oceans in 'shocking' decline
The oceans are in a worse state than previously suspected, according to an expert panel of scientists.
In a new report, they warn that ocean life is "at high risk of entering a phase of extinction of marine species unprecedented in human history".
They conclude that issues such as over-fishing, pollution and climate change are acting together in ways that have not previously been recognised.
The impacts, they say, are already affecting humanity.
The panel was convened by the International Programme on the State of the Ocean (IPSO), and brought together experts from different disciplines, including coral reef ecologists, toxicologists, and fisheries scientists.
Its report will be formally released later this week.
"The findings are shocking," said Alex Rogers, IPSO's scientific director and professor of conservation biology at Oxford University.
"As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised.
"We've sat in one forum and spoken to each other about what we're seeing, and we've ended up with a picture showing that almost right across the board we're seeing changes that are happening faster than we'd thought, or in ways that we didn't expect to see for hundreds of years."
These "accelerated" changes include melting of the Greenland and Antarctic ice sheets, sea level rise, and release of methane trapped in the sea bed.
Fast changes
"The rate of change is vastly exceeding what we were expecting even a couple of years ago," said Ove Hoegh-Guldberg, a coral specialist from the University of Queensland in Australia.
Fish at market Some species are already fished way beyond their limits - and may also be affected by other threats
"So if you look at almost everything, whether it's fisheries in temperate zones or coral reefs or Arctic sea ice, all of this is undergoing changes, but at a much faster rate than we had thought."
But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life.
Some pollutants, for example, stick to the surfaces of tiny plastic particles that are now found in the ocean bed.
This increases the amounts of these pollutants that are consumed by bottom-feeding fish.
Plastic particles also assist the transport of algae from place to place, increasing the occurrence of toxic algal blooms - which are also caused by the influx of nutrient-rich pollution from agricultural land.
In a wider sense, ocean acidification, warming, local pollution and overfishing are acting together to increase the threat to coral reefs - so much so that three-quarters of the world's reefs are at risk of severe decline.
Carbon deposits: for full article see
http://www.bbc.co.uk/news/science-environment-13796479
