GREAT BARRIER REEF

Great Barrier Reef

Great Barrier Reef

Introduction and Geographic Location

The Great Barrier Reef is a 1,200-mile long coral reef running along the Queensland coast of northeast Australia. Coral is created from masses of small marine animals called polyps. As polyps die, they leave their skeletons behind, which form the mass of the reef. New polyps grow on the old, creating a rainbow of colors. The Great Barrier Reef is the largest structure created by living organisms in the world. Parts of it are millions of years old. The reef is home to hundreds of species of fish, mollusks, and other marine life (Worrell, 2006).

Stromatolites are the oldest known fossils in the world, dating back more than 3 billion years. They are even more unusual in that the fossil form was found years before scientists found live specimens still developing. Stromatolites are formed by photosynthesizing cyannobacteria and other microbes that build “reefs” in the same way that coral grows. It is believed that cyannobacteria were most likely responsible for creating our oxygen atmosphere billions of years ago.

These bacteria were the dominant life form on the planet for over 2 billion years (Maxwell, 2008). Today, they are almost extinct and live in very few locations around the world. One place living Stromatolites can be found currently is in the Shark Bay World Heritage Area on Australia's west coast. The extreme salinity of the seawater, limited water circulation, warm temperatures, and presence of calcium carbonate create an environment ideal for the growth of stromatolites. Predators of the microbes cannot survive in this environment, because it has twice the salinity of regular seawater, so the cyannobacteria can grow unchecked.

Discussion

Ecological systems are changing, upset, and modified as a result of climate change. About 20-30 percent of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 2.7-4.5 degrees F (1.5-2.5 degrees C). Significant loss of biodiversity is projected to occur by 2020 in some ecologically rich sites, including the Great Barrier Reef and Queensland Wet Tropics. Other sites at risk include the Kakadu wetlands, southwest Australia, sub-Antarctic islands, and the alpine areas of both countries (Frankel, 2007).

In Latin America, by mid-century, increases in temperature and associated decreases in ground water are projected to lead to gradual replacement of tropical forest by savanna in eastern Amazonia. semiarid vegetation will tend to be replaced by arid-land vegetation. There is a risk of significant biodiversity loss through species extinction in many areas of tropical Latin America.

A typical example of the effect of climate change is the coral reef ecosystem. Coral bleaching, resulting from the breakdown of the symbiotic relationship between corals and unicellular algae (zooxanthellae) is often caused by the warming of sea temperatures. Reef coral are very sensitive to temperatures outside of their acceptable range; a rise of just 1 degree above long-term averages is enough to cause coral stress and bleaching. If these temperatures exceed average levels for a long period of ...