Why do corals turn white? Mass coral bleaching around the world
US scientists have reported that the fourth global coral bleaching event is taking place, causing coral to turn white in all oceans across the world.
Record-breaking ocean temperatures are wreaking havoc on coral reefs around the world, with devastating consequences.
According to the U.S. National Oceanic and Atmospheric Administration (NOAA), the fourth global mass coral bleaching event has been triggered by higher temperatures.
READ ALSO: Dubai floods cause havoc
READ ALSO: Videos show Copenhagen’s Old Stock Exchange up in flames, spire collapsing
Bleaching occurs when coral becomes stressed and turns white because the water it lives in is too warm. Coral reefs turn white because the stress caused by the heat makes them expel the algae living in their tissues, which are called zooxanthellae. These algae provide corals with essential nutrients through photosynthesis and give them their vibrant colors.
This bleaching phenomenon, in addition to being a worrying spectacle because it indicates the coral is ill or dying, is also seriously affecting marine life and ocean ecosystems.
Scientists in the U.S., Australia, Kenya and Brazil have expressed dismay at seeing coral being threatened or killed by warming oceans. From the Caribbean to the Great Barrier Reef in Australia, passing through the coasts of Tanzania, Mauritius, Brazil, Pacific islands, the Red Sea and the Persian Gulf, more than half of the world’s coral reefs have been affected.
READ ALSO: FBI launches criminal probe of Baltimore bridge collapse
El Niño has also contributed to this phenomenon
Global warming is driving rising sea surface temperatures as greenhouse gases emitted by burning oil, coal and gas are absorbed by the oceans. On top of this, the El Niño phenomenon has contributed to warmer temperatures since last year, although there are signs it is weakening.
Scientists warn that if global greenhouse gas emissions are not rapidly reduced, only a drastic, global shift in this direction will ensure that at least some coral remains. Coral reefs are not only necessary for marine biodiversity, they are also an early warning system that show the impacts of a warming planet on nature.