Thursday, October 6, 2011

Climate Change and Biodiversity Hotspots

Coral reefs are very productive marine ecosystems that provide habitat for many organisms and support extremely high levels of biodiversity. They also provide many ecosystem services that benefit tourism industries and fisheries. However, coral reefs are very sensitive systems and they are seriously affected by small changes in Earth’s climate. Global warming, and the subsequent rise in sea surface temperatures, is one of the main threats to coral reefs. Coral reefs can only tolerate a narrow range in ocean temperature. As ocean temperatures continue to rise, more coral reefs are becoming “bleached” and eventually become destroyed if the zooxanthellae don’t recolonize the coral. Ocean acidification is also a major threat to coral reefs. Due to the increase in atmospheric CO2, more CO2 is dissolving into the ocean. The increase in dissolved CO2 has caused the pH of seawater to decrease which means the oceans are becoming more acidic. The decrease in ocean pH makes it harder for marine organisms to form structures made of calcium carbonate (like coral). The increase in ocean acidity also erodes coral and makes it more prone to damage. Also the rising sea level associated with climate change has caused severe damage to many coral reef systems. Coral reefs require high amounts of light in order to grow and survive. As sea levels continue to rise, less light will reach coral reefs and many reefs may suffer. Intense conservation effort should be focused on coral reefs because they are very productive systems that support high biodiversity and provide many ecosystem services. It is estimated that coral reefs occupy less than one tenth of one percent of the world’s ocean but provide habitat for nearly 25% of marine organisms. Because coral reefs occupy a very small area and support extremely diverse communities, it would be extremely beneficial to direct even more focus and resources towards their conservation.

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