A recent study shows that the world’s coral reefs have been showing signs of strong bleaching due to global warming. In the 1980s bleaching was rare, occurring about once every 25 years. Now the rate has risen to about once every five years. Environmentalists predict that by 2050 bleaching will happen every year or two.
Bleaching is caused when warm water breaks down the algae inside the reefs. They provide food for the corals and keep them healthy. When algae fall off, corals lose their colour and can die within a short period of time. Even if the water surrounding the reefs gets colder again it may take years for the damaged reefs to recover completely.
While bleaching is especially a problem in the waters of the Carribean Sea and Western Atlantic, reefs around Australia and South Africa have hardly been hit. In addition to the warming temperatures of the oceans, coral reefs are also endangered by pollution and overfishing.
Coral reefs are an important ecosystem. They are home to 25% of all marine species and provide a habitat for countless types of fish. Reefs protect coastal regions from flooding and tidal waves. In addition, coral reefs are tourist attractions that lure millions of people every year. The tourist industry around the Great Barrier Reef in Australia, for example, is worth about 5 billion dollars a year.
- billion = a thousand million
- bleaching = to make something pale or white; when an object loses its colour
- break down = to change its structure
- Carribean Sea = sea between North and South America
- cause = the reason for something; why something happens
- countless = too many to be counted
- due to = because of
- ecosystem = all the animals and plants in a certain area and the way they live together
- endangered = to be in danger
- environmentalist = a person who cares about the world around us
- especially = above all
- global warming = when the temperatures in the atmosphere get higher because of increased amounts of carbon dioxide
- habitat = place to live
- in addition = also
- lure = attract; here: bring people to the area
- marine species = animals and plants that live in the oceans
- occur = happen
- overfishing = when you take too many fish from the sea so that the overall number of fish becomes too low
- pollution = when water becomes dirty so that it cannot be used anymore
- predict = to say that something will happen in the future
- protect = keep safe
- provide = give
- rare = not very often
- recent = a short time ago
- recover = to become as healthy as they were before
- sign = to show that something is happening
- study = a piece of work that is done to find out more about a certain topic
- surrounding = around
- tidal wave = very large ocean wave that flows over land and destroys things