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201630Mar16:16

Most severe coral bleach­ing ever of Great Bar­rier Reef documented

Infor­ma­tion
pub­lished 30 March 2016 | mod­i­fied 30 March 2016
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Coral bleachingAer­ial sur­veys of more than 500 coral reefs from Cairns to Papua New Guinea reveal that the most pris­tine sec­tion of the Great Bar­rier Reef is cur­rently expe­ri­enc­ing the worst, mass bleach­ing event in its his­tory, with the over­whelm­ing major­ity of reefs being ranked in the most severe bleach­ing category.

Helicopter aerialsurvey reefsThis has been the sad­dest research trip of my life,” says Prof. Terry Hughes, con­venor of the National Coral Bleach­ing Task­force. “Almost with­out excep­tion, every reef we flew across showed con­sis­tently high lev­els of bleach­ing, from the reef slope right up onto the top of the reef. We flew for 4000km in the most pris­tine parts of the Great Bar­rier Reef and saw only four reefs that had no bleach­ing. The sever­ity is much greater than in ear­lier bleach­ing events in 2002 or 1998.”

What causes coral to bleach?
Coral bleach­ing occurs when abnor­mal envi­ron­men­tal con­di­tions, like height­ened sea tem­per­a­tures cause corals to expel tiny pho­to­syn­thetic algae, called ‘zoox­an­thel­lae’. The loss of these colour­ful algae causes the corals to turn white, and ‘bleach’. Bleached corals can recover if the tem­per­a­ture drops and zoox­an­thel­lae are able to recolonise them, oth­er­wise the coral may die. Read more about coral bleach­ing.

Even more con­cern­ing, we haven’t yet found the south­ern limit of the bleaching
Prof. Terry Hughes, Direc­tor ARC Cen­tre of Excel­lence for Coral Reef Stud­ies, James Cook Uni­ver­sity, Australia »

We’ll be con­duct­ing fur­ther aer­ial sur­veys this week in the cen­tral Great Bar­rier Reef to iden­tify where it stops. Thank­fully, the south­ern Reef has dodged a bul­let due to cloudy weather that cooled the water tem­per­a­tures down,” said Hughes.

Mul­ti­ple research ves­sels and island research sta­tions are also doc­u­ment­ing the coral bleach­ing, with in-​water research con­firm­ing what is clearly seen from the air, that the major­ity of reefs north of Cairns are under­go­ing bleach­ing and that vir­tu­ally all species of corals are being affected.

We could see exten­sive bleach­ing even among the most robust ‘mas­sive’ corals,” says James Kerry, Project Man­ager of the National Coral Bleach­ing Task­force, who also par­tic­i­pated in the aer­ial sur­veys. “The fact that these hardy species have also turned white shows just how severe sum­mer con­di­tions have become on the north­ern Great Bar­rier Reef.

Res­i­dents we spoke to in Cape York were shocked by what they are see­ing, telling us that they had never expe­ri­enced any­thing like this before.”

Sci­en­tists in the water are already report­ing up to 50% mor­tal­ity of bleached corals,” says Prof. Hughes, “but it’s still too early to tell just what the over­all out­come will be. We will con­tinue to con­duct under­wa­ter sur­veys along the Great Bar­rier Reef in the com­ing months as the full impact of this mass bleach­ing event unfolds.”

Footage of the aer­ial sur­veys con­ducted early March 2016:


(Video credit: ARC Cen­tre of Excel­lence for Coral Reef Stud­ies /​James Kerry, 2016)

The Aus­tralian Gov­ern­ment has said in the past that the reef’s World Her­itage val­ues are safe. But if there are mass coral deaths from this event, what does that mean for the reef’s ongo­ing World Her­itage status?
« Der­mot O’Gorman, CEO of WWF-​Australia

Whether in Aus­tralia or else­where around the world, gov­ern­ments can­not con­tinue com­pla­cency on cli­mate change,” added O’Gorman. Local action against pol­lu­tion is also essen­tial to pro­tect the Great Bar­rier Reef.

If we don’t start to see some real lead­er­ship on the reef, it will be gone,” O’Gorman said.


(Source: ARC Cen­tre of Excel­lence Coral Reef Stud­ies media release, 29.03.2016; WWF Global news release, 29.03.2016)


UN Biodiversity decade

Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
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