[Coral-List] Bleaching in Australia

Hughes, Terry terry.hughes at jcu.edu.au
Fri Jun 17 00:00:59 EDT 2016


Dear Coral-List,

The Australian coral reef community have now undertaken bleaching and bleaching-mortality surveys around both the east and west coasts, and our focus has turned in the past few weeks to analysing large amounts of data collected at the peak of the bleaching, mostly in February to April. The corals are now are dead, still slowly dying or gradually recovering their colour. Further fieldwork will be undertaken in coming months to estimate the final mortality of corals from the 2016 bleaching and the shift in species composition.

On the east coast, we have conducted aerial surveys of more than 1100 reefs, from the northern Torres Strait adjoining PNG to the southern boundary of the Great Barrier Reef. Only 7% of these reefs had no bleaching, and 55% were severely bleached (affecting 30-60% or >60% of corals). We found a strong north-south gradient. The most remote part of the GBR,  the northern 800km stretch, has been very severely damaged. On the west coast, aerial surveys paint a similar picture, with little or no bleaching on Ningaloo Reef and further south compared to widespread damage on fringing reefs further north.

Underwater, research groups from many universities and government agencies have surveyed >200 reefs; (on the east coast) in the Torres Strait, along the GBR, in the northern and southern Coral Sea, and on subtropical reefs near Brisbane and in northern NSW, and (on the west) at all major fringing reef systems, and on offshore atolls in the Indian Ocean. There is a similar north-south gradient on both coasts.

The ARC Centre has examined "winner-loser" patterns of differential bleaching and mortality on 83 reefs along the GBR, from Townsville to the Torres Strait. In the north, even the hardiest corals have severely bleached. Across all taxa, our estimate of mortality in the northern and central regions combined is close to 35% - higher in the north, significantly lower in the middle. Further south there was little or no bleaching.

This is the third major bleaching of the GBR, and by far the worst in terms of the small proportion of unbleached reefs (7% versus close to 35% in 1998 and 2002), and the high proportion of severely bleached locations (55% of reefs surveyed in 2016 vs 18% before). We also expect the final death toll to be roughly 4 times greater this time. Bleaching in the northern GBR and Coral Sea is extensive down to 40m.

The footprint of the three GBR bleachings has varied each time, depending on where the water was hottest in each year. The cumulative footprints of the 1998, 2002 and 2016 events indicates that only a small fraction of the GBR has not yet been impacted by global warming, and many reefs have been affected twice or three times in just 18 years.

I will present a brief overview of these findings in a multi-authored talk at ICRS2016, on Tuesday at 11.15am in room 314.

Cheers,

Terry Hughes

From: Hughes, Terry
Sent: Tuesday, 12 April 2016 6:51 AM
To: coral-list at coral.aoml.noaa.gov
Subject: Bleaching in Australia

Dear Coral-List,

I'm writing to briefly update you on some of our research activities around Australia during the current bleaching event. The National Coral Bleaching Network was established last November, convened by the ARC Centre of Excellence for Coral Reef Studies, in partnership with the Great Barrier Reef Marine Park Authority, the Australian Institute of Marine Science, and seven other organisations. Severe bleaching is occurring now in the Torres Strait, northern and central Great Barrier Reef, parts of the Coral Sea, Northern New South Wales and coastal NW Western Australia.

We have nearly completed aerial surveys of the Torres Strait and GBR Marine Park. So far, we have flown seven flights in a chopper and plane, each one about 1000km long, scoring the extent of bleaching on 765 reefs from the northern tip of the Torres Strait to just south of Mackay. A final flight this week will cover the southern offshore tip of the GBR, bringing the sample size to 900 or so reefs. Multiple reefs zones within each reef have been assessed (upper slope, exposed and sheltered crest, inner and outer flat, patch reefs and lagoon). We've used Ray Berkelemans' scoring scheme to allow comparisons to the 650 reefs he scored in 1998 and 2002. The two observers on all flights in 2016 are myself and James Kerry.

In 2016, the proportion of reefs in the top two categories is 3-4 times higher than 1998 or 2002. The northern 1000km of the GBR has been severely damaged from Port Douglas up to PNG, and many corals there are already dying. Reefs from Cairns to Bowen are more "moderately" bleached, closer to the intensity of 1998 and 2002. Minimal or no bleaching is happening on macro-tidal reefs near Mackay, on Lord Howe Island and in the Cap-Bunks. Last week, I briefed the Australian Environment Minister on our preliminary aerial survey scores, and I have also consulted with the GBR tourism sector who understandably are deeply concerned about their natural assets and the way our results are portrayed in the media.

Since mid-February, twelve research vessel trips have been conducted (most are ongoing) by JCU, AIMS and GBRMPA along the GBR. These are providing site-level ground-truthing for the aerial surveys, and detailed information on the severity of bleaching at the colony level (ranging from zero to dying) along the GBR (including the TS) and in the inner Coral Sea. Many of these reefs are long-term sites that are repeatedly surveyed by AIMS and JCU researchers, allowing us to quantify shifts in species composition. In situ transects run last week by Morgan Pratchett show 50-75% bleaching on 14 reefs between Port Douglas and Cairns, matching the aerial survey scores. One underwater component includes measuring bleaching along depth gradients down to mesophotic reefs.

Other Taskforce teams are based primarily at Lizard, Orpheus, Heron and One Tree research stations. A sub-tropical network of researchers is investigation bleaching on the Solitary Islands in NSW and elsewhere on the east coast. Further work (chopper surveys and in situ surveys) is underway by the Torres Strait Regional Authority. GBRMPA's monitoring network of rangers, tour operators, etc. is also measuring bleaching and mortality. Bleaching is now well underway in northern nearshore parts of WA, but not on Ningaloo Reef or further south. The AIMS-UWA-Curtin researchers will shortly head out to census offshore atolls.

The summary above focusses on the initial task of documenting the severity and footprint of the bleaching around Australia, and we are now rapidly moving beyond that on the east and west coast to ask specific research questions. For example, on the GBR, we're now also looking at how many reefs have bleached 0-3 times in 1998, 2002 and 2016, and whether the in situ bleaching patterns we see today diverge on reefs with different histories. Other research areas underway include the molecular, physiological and ecological responses of zooxanthellae, microbes, corals and fish, using data gathered before and during (and soon, after) the bleaching event.

As for shade cloth, can I respectfully remind people that the GBR is >400,000km2 in area.

Best wishes, Terry

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January 6th, 2016

Dear Coral-list,

The Australian coral reef research community has established a National Coral Bleaching Taskforce, in anticipation of a potential bleaching event later this Austral summer. Projections by the Austrian Bureau of Meteorology and by NOAA suggest that bleaching could occur in March, although there is much uncertainty (and we hope it doesn't eventuate).

The purpose of the informal taskforce is to foster collaborative research on bleaching and to coordinate the efforts of over 300 researchers. The geographic scope is Australia wide, including tropical and sub-tropical reefs on the east and west coast. If bleaching occurs in 2-3 months' time, we will combine our efforts and resources to learn as much as we can from it.

Part of our planning includes an ongoing inventory of all of the existing data we collectively have from many locations, especially information on two earlier mass-bleaching events in 1998 and 2002.


Members of Taskforce (and associated organisations):

Terry Hughes (ARC Centre of Excellence for Coral Reef Studies; James Cook University)
Russ Babcock (CSIRO)
Maria Byrne (University of Sydney)
James Gilmour (AIMS Perth)
Scott Heron (NOAA, Townsville)
Ove Hoegh-Guldberg (ARC Centre, University of Queensland)
Janice Lough (AIMS Townsville)
Ryan Lowe (ARC Centre; University of Western Australia)
John Pandolfi (ARC Centre; University of Queensland)
David Wachenfeld (GBRMPA)
Shaun Wilson (DPaW)
James Kerry (ARC Centre; Project Manager)

If bleaching does occur, we will provide further updates. If you'd like to be involved please contact us.

Cheers, Terry


Professor Terry Hughes FAA
ARC Laureate Fellow
Director, ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD 4811
Australia



Professor Terry Hughes FAA
ARC Laureate Fellow
Director, ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD 4811
Australia

Link to Terry Hughes Google Scholar profile<http://scholar.google.com.au/citations?user=MhJ2LfsAAAAJ>

Email: terry.hughes at jcu.edu.au<mailto:terry.hughes at jcu.edu.au>
Phone: 61 (0)7 4781 4000
Website: http://www.coralcoe.org.au/postdocs/terry-hughes

ABC RN Breakfast: Interview on coral bleaching http://www.abc.net.au/radionational/programs/breakfast/widespread-coral-bleaching-detected-on-the/7212760

ABC TV Future Forum: Can coral reefs survive the 21st century (60 minutes)
http://www.abc.net.au/news/2011-08-01/can-coral-reefs-survive-the-21st-century/4121444

ABC TV (Catalyst): Future response of the Great Barrier Reef to climate change (8 minutes)
http://www.abc.net.au/catalyst/stories/3576802.htm




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