28 April 2017, Climate News Network, Sea floor erosion causes coral reefs to sink. Five US coral reefs are sinking beneath the waves due to the erosion of the sea floor, robbing coastal communities of their natural storm barrier. The world’s coral reefs are not just in hot water and under threat from acid attack; they may even be getting out of their depth. New research around five US coral reefs shows that even as sea levels rise, the sea floor around the reefs is being eroded. And coral growth simply may not be fast enough to keep up, which means that coastal communities in Florida, the Caribbean and Hawaii could become increasingly at risk from storms, waves and erosion. The news comes close after revelations that great tracts of Australia’s Great Barrier Reef, like other coral colonies, have been devastated by bleaching, as ocean temperatures rise above the levels that corals – animals that live in symbiosis with algae – can tolerate, and researchers have warned that this could soon be happening to reefs almost everywhere, every year. Coral under threat There is already widespread alarm among marine scientists as the seas become measurably more acidic due to an increase in levels of carbon dioxide in the atmosphere, and this too poses a threat to corals everywhere. But while researchers in the tropics had monitored the living reefs of the surface waters, hardly anybody had paid attention to the sea floor around the reefs. Now, scientists of the US Geological Survey report in Biogeosciences that – possibly as a consequence of the degradation of the reefs of the Florida Keys, the US Virgin Islands and the Hawaiian island of Maui – the sea floor is being scoured of sand and sediments, just as sea levels continue to creep to a predicted rise of up to a metre by 2100. Read More here
10 April 2017, The Guardian, Great Barrier Reef at ‘terminal stage’: scientists despair at latest coral bleaching data. ‘Last year was bad enough, this is a disaster,’ says one expert as Australia Research Council finds fresh damage across 8,000km. Back-to-back severe bleaching events have affected two-thirds of Australia’s Great Barrier Reef, new aerial surveys have found. The findings have caused alarm among scientists, who say the proximity of the 2016 and 2017 bleaching events is unprecedented for the reef, and will give damaged coral little chance to recover. Australia’s politicians have betrayed the Great Barrier Reef and only the people can save it | David Ritter Scientists with the Australian Research Council’s Centre of Excellence for Coral Reef Studies last week completed aerial surveys of the world’s largest living structure, scoring bleaching at 800 individual coral reefs across 8,000km. The results show the two consecutive mass bleaching events have affected a 1,500km stretch, leaving only the reef’s southern third unscathed.Where last year’s bleaching was concentrated in the reef’s northern third, the 2017 event spread further south, and was most intense in the middle section of the Great Barrier Reef. This year’s mass bleaching, second in severity only to 2016, has occurred even in the absence of an El Niño event. Mass bleaching – a phenomenon caused by global warming-induced rises to sea surface temperatures – has occurred on the reef four times in recorded history. Prof Terry Hughes, who led the surveys, said the length of time coral needed to recover – about 10 years for fast-growing types – raised serious concerns about the increasing frequency of mass bleaching events. “The significance of bleaching this year is that it’s back to back, so there’s been zero time for recovery,” Hughes told the Guardian. “It’s too early yet to tell what the full death toll will be from this year’s bleaching, but clearly it will extend 500km south of last year’s bleaching.” Read more here