Habitat Destruction Due To Climate Change

Question: How habitat destruction (Great Barrier Reef) occur due to climate change? Answer: The grate barrier reef is located along the coast of Queensland in northeast of Australia. When water temperatures rises due to climate change corals experience stress because of its sensitivity to small changes in temperature. In an event that this rise in water temperature persists for a number of weeks the zooxanthellae that the corals depend for some of its food leaves the corals which consequently turn white in color in a process called bleaching. The bleached coral is weak and vulnerable and can be easily attacked and destroyed by disease. (Hall McNiven, 1999) Climate change also brings about ocean acidification. When Carbon (IV) oxide / carbon dioxide (CO2 ) gas emitted to the atmosphere finds its way to the ocean the PH of the ocean water reduces in a process called ocean acidification. The CO2 reacts with water to form weak carbonic acid that reduces alkalinity of water. With reduced water PH the corals can not absorb the calcium carbonate that they need for strong skeletons. The skeletons that support corals and reefs will be weak and dissolves in water thus destroying corals. (McGregor, 1974) Sea level rise due to climate change cause damage to the corals. The rise in sea level is occasioned by high water temperatures that cause water to expand occupying more space and meting of glaciers. This increased volume of water leads to intrusion of salty waters from mangrove and salty water habitats to fresh water habitats where corals are located; since most of the Great Barrier Reef coastline is low-lying the fresh water habitat around it will start being salty and acidic thus destroying the corals. Graph below shows GBR calcification rate from around 16th century to 20th century. (Adopted from Reef Resilience) From the graph it can be depicted that the rate of calcification of corals has reduced from around 18th century when global warming increasingly become an issue and the same trend is expected continue due to persistent rise in sea level associated with climate change. Calcification is an important process that enables strong coral skeleton formation. (Great Barrier Reef Marine Park Capricornia Section, 1980) Graph below shows Global mean sea level rise verses Time. (Adopted from Reef Resilience) From the graph its evident that sea level will continue rising thus corals are in more danger from the effects of climate change. (Dash, 2007) From the recent studies it is estimated that third of the Great Barrier Reef has been lost due to the process called bleaching associated with climate change. Measures put in place to mitigate rise in sea level has been slow in producing results due to unequal commitment of countries of the world to stop or reduce carbon dioxide emission which is the major course of global warming that brings about rise in sea levels. It is estimated that sea level as raised to about 0.68m and by the year 2100 the level of rise will be 0.9 m. Impacts of habitat destruction to the threatened species The coral habitat is relied by so many species. Starting with the microscopic organisms such as bacteria fungi and virus that depend on the corals for protection and food to bigger living creatures like fish, the coral reef is home to many species. These living things create a balanced food web that each and every species depends on. The threatened species that depends majorly on the corals will be adversely affected in an event of the coral distraction. One of the food chain within coral habitat is that of larger planktons being food for bait fish which in turn are feed on by seabirds, predatory fish and dolphins. Some of the protected species in Great Barrier Reef include; green sawfish, birds, pipefish, helmet shells, great white shark, marine turtles and seals. The animals that depend on coral reef for food and habitats like fish will definitely reduce in number when corals are destroyed. This type of fish faces greater challenges in terms of adapting to the new environment because its ecological niche is very narrow. Many larger fish such as sharks, sea birds and marine animals depend on smaller fish for food. In an event that the population of the small fish that depend on coral for food and shelter has significantly reduced there would be food scarcity for bigger fish and other sea mammals. This is therefore a long food chain that is balanced and once one part of the chain is disturbed the rest of the species in the chain will be affected more so the endangered species because of their fragile food niche. (SaÃÅ' nchez-Arcilla, 2006). References Dash, S. (2007). Climate change. New Delhi: Cambridge University Press, India. Great Barrier Reef Marine Park Capricornia Section. (1980). [Townsville, Q.]. Hall, J. McNiven, I. (1999). Australian coastal archaeology. Canberra, Australia: ANH Publications, Dept. of Archaeology and Natural History, RSPAS, Australian National University. McGregor, C. (1974). The Great Barrier Reef. Amsterdam: Time-Life Books. SaÃÅ' nchez-Arcilla, A. (2006). Coastal Dynamics 2005. Reston, VA: American Society of Civil Engineers.