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Coral Bleaching Due to Climate Change 1Alexis EarlBIOL-41300 Fall 2016November 18,2016Coral Bleaching Due to Climate ChangeCoral reefs are the oldest most biodiverse ecosystems on the planet.They are the breeding ground of tropical oceans.Although they make up less than one percent of the world’s oceans,approximately twenty-five percent of all fish species are dependent on them in one way or another. Corals provide whales,turtles,sharks,and approximately two-hundred other species of fish a home to where they can feed and breed (Thibaut et. al 2012).They harbor complex and vulnerable ecosystems,that are relatively unknown.New research is providing scientists with information that could help corals keep their vibrant colors.Corals are mainly found in warmer shallower water, because they rely on the warm sunlight to grow and produce oxygen.Reefs are formed over a period of time by tiny polyps. Hundreds,even thousands of polyps can make up a coral. Polyps are related to jellyfish and sea anemones.A polyp is mostly stomach, with a mouth on top.It sits in a hard skeleton that is part of the reef.The polyp takes in dissolved minerals from the water and mixes them with proteins.Then it rises from its skeleton,leaving space below.It deposits calcium carbonate,limestone,into the space (McClanhan, et. al., 2007).Over time,each polyp builds its own skeleton and adds to the structure of the reef. What gives the polyp all the energy for all this building? A unique partnership between zooxanthellae and the
Coral Bleaching Due to Climate Change 2polyps is formed.Zooxanthellae use energy from the sun to photosynthesize, and they produce up to ninety-five percent of the food that the coral needs to survive.As animals,the corals emit nutrients valuable to the algae,and they give the zooxanthellae a place to reside which forms a symbiotic relationship between the organisms. The zooxanthellae are also what gives the coral their vibrant colors. Polys have stinging tentacles that they use to paralyze and prey on smaller organisms,plankton.As they grow,they divide and reproduce.Their skeletons connect with each other,forming complex coral layers and colonies.When corals are stressed by conditions inthe environment,such as an increase in the temperature of the ocean water,they discard the zooxanthellae that are living in a symbiotic relationship with the polyps,causing the coral to turncompletely white.This phenomenon is known as coral bleaching.Coral reefs are one of the marine ecosystems that are most greatly affected by climate change because they live in the upper thermal limits where sunlight can reach them.To survive coral need sunlight,warm water temperature,clean and clear water,and salt water.