NOAA Links Third Global Coral Bleaching to El Niño and Warm Oceans

Summary: NOAA links the third global coral bleaching currently afflicting reefs in Earth's three largest oceans to El Niño and warm oceans.

NOAA's Coral Reef Watch Outlook for October 2015 to January 2016 predicts coral bleaching (Alert Level 1) and reef mortality (Alert Level 2) mainly in northern Atlantic and Pacific Oceans: NOAA Satelitte and Information Service, Public Domain, via NOAA

The National Oceanic and Atmospheric Administration (NOAA) is identifying the extensive bleaching now afflicting reefs in Earth’s three largest oceans as the third global coral bleaching since 1998 and is linking the event to a strong El Niño and rising ocean temperatures.

“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,” Mark Eakin, coordinator for NOAA’s Coral Reef Watch program, explains.

NOAA’s Coral Reef Watch monitors physical environmental conditions of coral reef ecosystems and issues predictions for periods of four months to coincide with a bleaching season’s typical length. Bleaching that appeared in August in the Atlantic waters of the Florida Keys and South Florida is now diminishing there but is predicted to hit reefs from the Caribbean to North Africa in the October 2015 to January 2016 quarter. NOAA estimates that almost 95 percent of U.S. coral reefs will experience bleach-causing conditions by the end of 2015.

The strong El Niño that began in March and April is expected to peak in November and December and to trend significantly far into 2016.

Although scientists do not understand fully the triggers for switches between warm ocean water phase El Niño and cool phase El Niña, the effects of El Niño are known: prolonged, 3-month average rises of at least 0.9 degrees Fahrenheit (0.5 degrees Celsius) in sea surface temperatures (SSTs) in the east-central Pacific Ocean.

Alert Level 2, warning of reef mortality, applies mainly to the north Atlantic and Pacific oceans through January 2016 and to the Indian and South Pacific oceans for February to May 2016.

This third cycle of severe, long-term bleaching first appeared in summer 2014 in Hawaii. The remoteness of the well-protected, 140,000-square-mile Papahānaumokuākea Marine National Monument has failed to shield tiny Lisianski Atoll’s 378-square-mile Neva Shoals from the lethal finale of extreme bleaching.

“Last year’s bleaching at Lisianski Atoll was the worst our scientists have seen. Almost one and a half square miles of reef bleached last year and are now completely dead,” Randy Kosaki, NOAA’s deputy superintendent for the monument, notes.

Bleaching occurs as a response to environmental stressors, such as ocean temperature increases. When water temperatures rise, corals expel the microscopic algae, known as zooxanthellae (zo-zan-THELL-ee), that normally live in a beneficial relationship in coral tissues by passing sugar as a by-product of photosynthesis to coral hosts. Rising temperatures cause the algae, which are responsible for the reef’s spectacular colors, to shut down on sugar and to pass harmful free radicals instead. Algal leave-taking results in the stark whiteness known as coral bleaching.

With adequate recovery time, reefs tend to withstand mild bleaching. Severe, long-term bleaching, however, opens the weakened corals to disease and can be lethal. Reef death reduces shoreline protection and marine life habitats, both of which have powerful ecological and economic impacts.

NOAA's Coral Reef Watch Outlook for February to May 2016 predicts coral bleaching (Alert Level 1) and reef mortality (Alert Level 2) mainly in Indian and South Pacific Oceans: NOAA Satellite and Information Service, Public Domain, via NOAA

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

NOAA 2015 Coral Reef Watch Outlook Oct 2015 to Jan 2016: NOAA, Public Domain, via NOAA News @ http://www.noaanews.noaa.gov/stories2015/images/v3_ss_outlook_cfs_rank12_20151004_for_20151018to20160131_45ns_new_text_2500x914_300dpi%20(2).png

NOAA 2016 Coral Reef Watch Outlook Feb to May 2016: NOAA, Public Domain, via NOAA News @ http://www.noaanews.noaa.gov/stories2015/images/v3_ss_outlook_cfs_rank12_lw17-33_ic20151004_f20160201-20160529_45ns_new_text_2500x914_300dpi%20(2).png

For further information:

Byrne, Kevin. "El Nino to Exacerbate Third Global Coral Bleaching Disaster." AccuWeather. Oct. 26, 2015.
Available @ http://www.accuweather.com/en/weather-news/el-nino-to-exacerbate-third-global-coral-bleaching-event-record-hawaii-main-islands/53106387

Langenheim, Johnny. "El Niño would be a disaster for the world's coral reefs."The Guardian. June 5, 2014.
Available @ http://www.theguardian.com/environment/blog/2014/jun/05/el-nino-coral-reef-earth-amazons

"NOAA declares third ever global coral bleaching event." NOAA News. Oct. 8, 2015.
Available @ http://www.noaanews.noaa.gov/stories2015/100815-noaa-declares-third-ever-global-coral-bleaching-event.html