§ Norman BakerTo ask the Secretary of State for Environment, Food and Rural Affairs if she will make a statement on the incidence of oxygen-free zones in the oceans. [165590]
§ Mr. MorleyA recent report by the United Nations Environment programme drew attention to a number of cases across the world where there are regular instances of oxygen deficiency, often caused by excessive inputs of nutrients from land based sources. This underlines the need for action to limit the input of nutrients, and the UK has supported the UNEP Global Plan of Action on land-based sources of pollution which is seeking to address this.
There have been no cases of oxygen levels in UK coastal waters falling so low as a result of anthropogenic nutrient inputs as to be a cause for concern, e.g. through fish kills. Historically, there have been oxygen depletion problems affecting the passage of migratory fish in certain estuaries due to the direct discharge of sewage. The problems no longer exist due to the effective management of the discharges.
There are some areas where nutrient levels are high as a result of anthropogenic nutrient inputs, and in a few cases this has resulted in undesirable changes to the water environment. We have taken action to reduce nutrient inputs in these cases, through improved treatment of sewage and through designating Nitrate Vulnerable Zones o control the use of fertilisers and slurry on farmland.
The Department is committed to take further action to address diffuse water pollution. Officials are undertaking a range of work to identify diffuse pollution problems and the best ways to tackle them across all activities and a formal consultation on a range of options to tackle water pollution from agriculture will be issued shortly.
In some places, for example systems with limited water exchange, it is natural for there to be areas where oxygen levels are low without anthropogenic nutrient input.