ENVIRONMENT:FRIENDS OF the Irish Environment has urged farmers and foresters to exercise care in applying nitrogen, following publication of a study which identifies 20 marine "dead zones" off the coastline.
The 20 polluted areas, extending right around the 7,500km (4,660 miles) coastline, are among 400 such "dead zones" named in the academic journal Science last month.
Chemical fertiliser run-off and the burning of fossil fuels have been identified as the main contributors to eutrophication, and depletion of marine life in such "dead zones", due to low oxygen levels.
The study by Robert J Diaz of the Virginia Institute of Marine Science, USA, and Rutger Rosenberg of the University of Gothenburg, Sweden, notes that dead zones have spread "exponentially" since the 1960s. Dead zones reported in more than 400 coastal ocean systems affect a total area of more than 245,000 square kilometres (95,000 square miles), and are "probably a key stressor on marine ecosystems", the scientists state.
The 20 areas identified in Ireland range from Broadmeadow estuary in north Dublin to the Barrow estuary and Dungarvan harbour in the southeast, to the Bandon and Lee (Tralee) estuaries in the southwest and up to Killybegs harbour and Donegal bay in the northwest. Strangford Lough and inner Belfast Lough are also identified in the Irish list.
The authors state that the key to reducing dead zones involves keeping fertilisers on land and ensure no run-off to sea. Even the "smallest stream in the uplands" can transport nitrogen fertiliser into rivers and estuaries, the Friends of the Irish Environment (FIE) organisation warns, responding to the report.
It notes that the authors describe such dead zones as one of the "major global environmental problems", with "no other variable of such ecological importance" having "changed so drastically over such a short time".