Coral bleaching hits critical point: 95pc of US reefs at risk

8 Oct 2015

The third global coral bleaching event on record is upon us, with the spread of warming waters damaging the underwater ecosystems, starting in the north Pacific in the summer of 2014 and hitting the south Pacific and Indian oceans this year.

It seems that the US coast is being hit particularly hard, with 95pc of its coral reefs becoming exposed to bleaching conditions before the end of this year, according to scientists.

The latest base to come under threat is coral off the Hawaiian Islands, where bleaching is intensifying and is expected to continue for at least another month.

Areas at risk in the Caribbean over the coming weeks include Haiti, the Dominican Republic and Puerto Rico, and from the US Virgin Islands south into the Leeward and Windward islands.

Corals can recover from mild bleaching, however this global spread could prove lethal.

Coral reef bleaching

“Last year’s bleaching at Lisianski Atoll [pictured above] was the worst our scientists have seen,” said Randy Kosaki of the US National Oceanic and Atmospheric Administration (NOAA).

“Almost one-and-a-half square miles of reef bleached last year and are now completely dead.”

After corals die, reefs quickly degrade and the structures corals build erode. Considering it is these environments where many of the world’s fish species live and prosper, this can only be bad news.

Bleaching happens when corals are exposed to stressful environmental conditions, with warming waters an obvious concern.

Warming waters cause the expulsion of the symbiotic algae living in coral tissues, causing corals to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease.

“The coral bleaching and disease, brought on by climate change and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world,” said Mark Eakin, coral reef watch coordinator at NOAA.

“As a result, we are losing huge areas of coral across the US, as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”

Global bleaching events are a modern phenomenon, with the first occurring in 1998, driven by strong El Niño and La Niña storms – the second was only five years ago.

Main image via Shutterstock, body image via NOAA

Gordon Hunt was a journalist with Silicon Republic