Coastal waters strangled by green slime, warns WWF

Marine wildlife in Britain's coastal waters is being choked by an insidious form of pollution that starves the habitat of oxygen, environmentalists warned.

The World Wide Fund for Nature said Britain's coasts were being strangled with blankets of green slime that thrived on mineral nutrients from industrial and domestic waste. Although the Government recognised there was a problem with nutrient pollution in freshwater lakes and rivers, it had ignored it as an issue for marine wildlife, the WWF said.

Simon Vowles, the charity's marine pollution officer, said: "Estuaries are some of the UK's most biologically diverse areas and are the interface between fresh and salt water, where land-based pollution becomes highly concentrated. Current government policy is threatening and reducing that diversity."

A build-up of mineral nutrients, notably phosphorus and nitrogen, caused algae to grow so fast that it robbed the surrounding environment of oxygen – a process called marine eutrophication.

The WWF claimed there was evidence to show that some tidal rivers and estuaries had levels of nutrients 100 times greater than the level that the Government recognised as causing eutrophication. "The evidence of the problem is there for all to see – blankets of algal weed, choking the life from our estuaries and coastal waters," Dr Vowles said.

Fish farms in Scotland had been accused of producing nutrient pollution and "toxic blooms" of algae that had affected the local shellfishing industry, the WWF said.

Eelgrass meadows, which are important habitats for marine wildlife, are among the first to suffer from algal blooms. The WWF said only 20 of Britain's 155 estuaries had eelgrass meadows bigger than one hectare in size, a decline of 85 per cent in the past 80 years.

"This problem will not go away unless the Government changes its policy and tackles nutrient pollution at source. The main sources of nutrients – nitrogen and phosphorus – are agriculture, sewage, aquaculture and industrial discharges," the WWF said.

Matthew Davis, a campaign director, said that the current policy of designating a Marine Protected Area was not enough and that the Government should consider an Oceans Act to protect marine areas and control the amount of pollutants that could be released into the sea.

The charity said that cutting down on the release of nutrients could help the recovery of natural habitats, such as underwater meadows of eelgrass.