|
|||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||
 |
|
 |
 |
 |
|
|
Coral Reefs Coral reefs are among the most beautiful natural phenomena of this planet. They contain such a diversity of life forms, they have often been called the "rainforests of the sea". Corals, plants, sponges, sea anemones, sea urchins, star fish, sea horses and exotic colourful fish make their home in the underwater world of the reefs. Millions of people live on islands built by or surrounded by coral reef systems and depend upon these reefs for food and prosperity. Alarmingly, considerable degradation of the coral reef systems has been observed in recent years. In 1992 scientists at the seventh International Coral Reef Symposium in Guam estimated that 10% of the world's coral reefs were effectively lost, and another 30% are likely to suffer a significant decline over the next twenty years. To focus the world's attention on the plight of coral reefs, governments, organizations, and individuals around the world recognised 1997 as the International Year of the Coral Reef (IYOR). Because coral reefs are highly complex ecosystems, only recently have major studies begun to unravel the causes of this degradation. Both natural and human-related disturbances affect coral reef ecosystems, but recent evidence suggests that it is mainly the unrelenting barrage of human-induced stresses that is causing the damage. These include steady increases in sediment runoff onto reefs; excessive mining of coral sand and rock for building; increases in pollution, particularly from agriculture and domestic sewage; and chronic overexploitation of reef resources that have resulted in widespread reef damage and, in some cases, ecological collapse. The most endangered reefs are located along some of the world's most heavily populated coastlines--Asia, East Africa, and the Caribbean, including the Florida Keys (see Map). Coral reefs also suffer from the forces of nature such as severe storms, flooding, temperature extremes, events linked to El Nino and disease/ While some species of reef-building corals are known to have survived previous episodes of natural global warming, future man-caused global warming could take a heavy toll on existing coral reefs. Increases in sea temperature of only one or two degrees over five to ten weeks during the summer can stress corals, causing them to expel the symbiotic single-celled algae known as zooxanthellae that live within the thin layer of live coral tissue. The algae not only give corals their brilliant colours (without them corals appear white or "bleached") but also supply them with the energy and nutrients they need to build reefs. Corals cannot survive without these algae, but if the stress is short lived, bleached corals may recover, with, however, reduced growth and weakened reproductive capabilities. In a warming environment, the frequency of sea-warming episodes such as those observed during El Nino-related episodes will likely increase, resulting in more frequent bleaching events. Slow sea level rise, expected in a warming atmosphere, would encourage vertical coral growth, provided other factors do not kill off new growth. Although WMO does not have a specific programme or project upon coral reefs, the causes of the degradation of coral reefs do come under the purview of WMO. WMO is monitoring climate change and, with other agencies, analysing its actual and potential effects globally. The WMO/UNEP Intergovernmental Panel on Climate Change is preparing a comprehensive assessment of the socio-economic impacts of climate change and an evaluation of current scenarios of greenhouse gas emissions. A key strategy for protecting the world's coral reefs lies in educating the public to the devastating effects that their actions can have on these beautiful formations. Over-fishing, careless tourism and the use of the sea as a dumping ground must be stopped. Individuals are encouraged to put pressure on their local, regional and national governments to promote the preservation of the world's coral reefs. There is a clear need to develop a new paradigm for the administration of coral reefs, a new perspective that might also be a framework for our management of the Earth as a whole. Follow these links to find out more. • San José State University • World Resources Institute • Action Atlas - Trouble in Paradise - The National Oceanographic and Atmospheric Administration - The Intergovernmental Panel on Climate Change - The World-Wide Fund for Nature |