UN Warns Ocean Dead Zones on the Rise, ENS 10/19/06
Source: Environmental News Service
BEIJING, CHINA - The number of dead zones in the world's oceans and seas has increased dramatically in the past two years, endangering fish stocks and the people who depend on them for food and livelihoods, the United Nations Environment Program (UNEP) warned Thursday. The latest study finds at least 200 dead zones across the world, up from an estimated 149 only two years ago.
The new scientific estimates of dead zones, areas where algal blooms remove oxygen from the water, were released at a UNEP marine pollution meeting in Beijing.
The conference, which began Monday and extends through Friday, is reviewing the UNEP global program of action for protection of the marine environment. Delegates from 115 countries are attending the intergovernmental review of the 10 year-old initiative.
The Gulf of Mexico dead zone grows to more than an 18,000 square-kilometers each year. (Photo courtesy Carleton College)
The algal blooms that cause dead zones are triggered by nutrients from agricultural runoff, sewage and animal wastes, and pollutions from the burning of fossil fuels.
The low levels of oxygen in the water make it difficult for fish, oysters and other marine creatures to survive as well as important habitats such as sea grass beds.
Some of the earliest recorded dead zones were in places like Chesapeake Bay in the United States, the Baltic Sea, the Kattegat, the Black Sea and the northern Adriatic Sea.
The most well-known area of depleted oxygen is in the Gulf of Mexico - directly linked to nutrients or fertilizers brought to the Gulf by the Mississippi River.
The report identifies new dead zones in the Finland's Archipelago Sea, the Fosu Lagoon in Ghana, the Mersey Estuary in the United Kingdom and Uruguay's Montevideo Bay. Others have been appearing off South America, China, Japan, south-east Australia and New Zealand.
The report warns that the pollution that contributes to dead zones shows few signs of decreasing. Nitrogen exports to the marine environment from rivers, for example, are expected to rise globally by 14 per cent by 2030 when compared with the mid 1990s.
"There are numerous compelling reasons for combating pollution to the marine environment," said UNEP Executive Director Achim Steiner. "These range from public health concerns to the economic damage such pollution can cause to tourism and fisheries.
Scientists fear climate change could decimate coral reefs. (Photo courtesy Carleton College)
UNEP released another report Thursday that warned that coral reefs worldwide are facing major threats from pollution and climate change. The ability of coral reefs to survive warming waters may "crucially depend" on the levels of pollution to which they are exposed, the report said.
"If we fail to protect the coastlines from unchecked piecemeal development, or protect the water sheds from deforestation, huge amounts of sewage and sediment loads will reduce the ability of reefs to recover dramatically," said Christian Nellemann, a researcher with UNEP's rapid response team. "Once they are overgrown, it is difficult for them to recover, and over time they change or even die entirely."
The study is based on surveys carried out between 2004 and 2006 following damage caused to reefs world-wide in 1997-1998 when surface sea temperatures reached up to 34 degrees Celsius.
Corals in an estimated 16 per cent of the world's coral reefs suffered up to 90 per cent mortality as a result of mass bleaching, with reefs across the Indian Ocean, including around the Comoros, La Reunion, Madagascar, Mauritius and Seychelles, among those severely damaged.
But soft coral cover and stony coral increased rapidly in areas least affected by coastal development.