Losing the Pristine: Coral Bleaching strikes in North Great Barrier Reef

Unfortunately, the predictions raised in my blog post last month about the fate of the Great Barrier Reef (GBR) in response to the ongoing mass global bleaching event have come true. Throughout March, coral reefs located on the far north section of the GBR have suffered variable but widespread bleaching.

In particular, the area north of Cairns has been affected the most severely, such as Lizard Island.

Dr. Russell Reichlet, Chairman of the Great Barrier Reef Marine Park Authority (GBRMPA), says that surveys conducted in February indicate Sea Surface Temperatures as high as 33˚C in the area¹. If you recall from my previous post, high temperatures are one of the primary contributors to coral bleaching. Dr. Reichlet also reported that there is severe bleaching on the inshore reefs and moderate bleaching on the mid-shelf reefs of this Lizard Island area. He also cites that reports of the mid-shelf and outer reefs surveyed further south showed only minor to moderate bleaching, which is typical during this time of the year for that area. The main concern is the north.

While coral bleaching in any case is a tragedy, it is especially devastating right now for Australia. The northern GBR has been established as the most pristine section of the entire 300 km (1800 miles) of coastline it covers. Due to it’s isolation up north, farther from the heavy tourism that hits the southern GBR, this area is home to previously very healthy reefs. In contrast, reports of high cloud cover and heavy rainfall have mitigated the effects of the bleaching event in the central and southern GBR¹. These factors do so by keeping sea surface temperature (SST) down, thus providing some relief from the heat stresses that cause corals to bleach¹.

It appears that right now the far north GBR is experiencing the worse part of the bleaching event. The National Oceanic and Atmospheric Administration (NOAA) uses satellites and modeling to create Regional Coral Bleaching Thermal Stress Gauges, which provide current and future predictions of the severity of bleaching in a given area². The most recent data on the Far Northern GBR is pictured below.

The 4 maps show the current conditions and projections for 1-4, 5-8, and 9-12 weeks out. It is evident from this visual representation that the reef is undergoing the most severe bleaching currently. There are mixed levels of severity projected for the next 1- 4 weeks, with some areas still in Alert Levels 1 and 2, while the majority of the area appears to reduce to a Watch level. The purpose of these different levels are to assist the overseeing authorities of the reefs in how to respond to this event.

NOAA also utilized its data to create a timescale graph of the SST of the reef, pictured below.

It is apparent from this graph that the Far Northern GBR is currently exceeding its bleaching threshold SST, as well as its Maximum Monthly Mean SST and Monthly Mean Climatology.

While I have not been able to find any current research papers regarding what is happening, the World Wildlife Fund (WWF) in Australia posted a video and photographs on March 1^st showing the current state of a reef on Lizard Island. These are included below.

Fortunately, a National Coral Bleaching Taskforce composed of 10 research institutions and over 300 scientists has been established to coordinate research on this event³. Additionally, on March 14^th the WWF-Australia called for an urgent federal funding of $1 million in order to monitor the bleaching in the Far Northern GBR. As mentioned above, this area is moderately isolated and thus requires significant effort to get scientists and divers to the area (hence the $1 million asking price).

Time will tell what happens next in the GBR. Hopefully, the bleaching will diminish over the next few weeks and more reports will be available quantifying the severity of damage in the northern reefs. Until then, stay tuned.

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References:

1. “Reef coral bleaching intensifies in far north.” Great Barrier Reef Marine Park Authority. N.p. 03 March 2016. Web. http://www.gbrmpa.gov.au/media-room/latest-news/coral-bleaching/2016/reef-coral-bleaching-intensifies-in-far-north
2. “Far Northern GBR 5-km Bleaching Thermal Stress Gauges.” NOAA Satellite and Information Service Coral Reef Watch.p. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
3. “Coral-List Great Barrier Reef bleaching update.” Hughes, Terry. N.p. 1 March 2016. Web. http://coral.aoml.noaa.gov/pipermail/coral-list/2016-March/016625.html

Images:

4. Great Barrier Reef Basin. Image. Web. N.d. http://www.mappery.com/map-of/Great-Barrier-Reef-Basin-Map
5. Lizard Island, Australia. Image. Vacationstogo. Web. 2016. http://www.vacationstogo.com/cruise_port/Lizard_Island__Australia.cfm
6. Lizard Island. Photograph. LizardIsland. Web. 2012. http://www.lizardisland.com.au
7. Far Northern GBR Satellite Coral Bleaching Alert Area and Outlook. Image. NOAA Satellite and Information Service Coral Reef Watch. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
8. Far Northern GBR. Image. NOAA Satellite and Information Service Coral Reef Watch. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
9. Coral Bleaching, Lizard Island, Great Barrier Reef. Photograph. WWF-Australia. Web. 1 March 2016. http://www.wwf.org.au/?15680/Worst-coral-bleaching-on-Lizard-Island-since-2002-a-cause-for-concern

Video:

10. WWF-Australia. “Coral Bleaching, Lizard Island, Great Barrier Reef.” Video. Web. 1 March 2016. https://youtu.be/isRIlXNY1Jc?list=PLtVYm_50W1qdlMhnRumj9qPovRaGPE3C8