Jane Luo - Coral Bleaching
Homes to more than 4,000 species of fish, 700 species of coral, and thousands of other animal and plant species, coral reefs play significant roles in the life cycles of at least a quarter of the world’s marine life. Coral reefs can be found in warm, clear, and shallow waters in oceans all around the world, and they are commonly known for their vibrant coloration and capacity to support diverse ecosystems.
Corals have a mutualistic relationship with zooxanthellae, which are microscopic algae that live in their tissues. The coral provides for a protected environment for the algae to photosynthesize in, and the algae provides the coral with essential nutrients and gives the coral its bright color. However, if the relationship between the two species becomes stressed due to external factors-increased ocean temperatures or pollution- the algae is expelled from the coral’s tissue. The coral loses its primary source of nutrients, becomes more vulnerable to disease, and turns white as a result of a process known as coral bleaching.
Coral bleaching has become a critical issue in the past few years due to rising ocean temperatures and the increasing acidification of ocean water. The extraction and burning of fossil fuels by humans has significantly increased greenhouse gas emissions into the atmosphere, leading global warming and heating of the world’s oceans; these temperatures are placing external heat stress on the coral in reefs, leading to bleaching. Additionally, some carbon dioxide emissions are absorbed by the ocean and forms a mild acid when dissolved in water, contributing to a slight increase in the acidity of the ocean and devastating thermally sensitive coral reefs.
The most prominent example of coral bleaching is the extensive damage inflicted on the Great Barrier Reef, which extends for more than 1,400 miles off the northeastern coast of Australia. Thirty percent of the coral in the Great Barrier Reef perished in 2016, and an additional twenty percent followed in 2017 as a consequence of severe consecutive coral bleachings. If we do not take measures to minimize the impact of additional coral bleaching events on coral reefs, our reefs may never recover and continue to support future marine life.
What are other causes contributing to declining coral reefs?
Why is coral reef preservation important?
What can we do to minimize the risk of future bleaching events?
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