Great Barrier Reef devastated againA few weeks ago we reported on the continuation of the catastroph

Great Barrier Reef devastated againA few weeks ago we reported on the continuation of the catastrophic bleaching event that has been killing coral for the last two years (see http://bit.ly/2onrIvb and links therein), commenting that urgent aerial surveys were being undertaken to assess the extent of the damage, and it isn’t reassuring. Much more of the reef has now been affected across a swathe extending several thousand km north to south, and the northwards two thirds of the entire reef has now been affected. The long persistence of the event affects the possibilities of recovery, since such extended stress usually results in death for the corals. This is the worst event to affect this wonder of the world in human memory. Last year the northern stretches were most affected, but this year the central zone (the most critical to the tourist industry that brings in several billion dollars yearly) suffered extensively. Last year’s warm seas were partly driven by the most intense El Nino event since 1998 (see http://bit.ly/2a83bza and links therein for our coverage of its effects), the worrying thing about this year is that El Nino has ended, and the heat persists. Sadly hopes that cyclone Debbie (see http://bit.ly/2p0Yt1r) would bring cooler water have not been borne out. Adding insult to injury many unbleached corals were battered by the cyclone, particularly in the Whitsunday Islands. Runoff from the storm is now pouring out of rivers onto the cyclone bashed corals, setting back large investments in improved water quality.Corals take a decade or so to recover from the worst effects of a bleaching event, but if they start happening with greater frequency then this is impossible, especially is the bleached zones are no longer connected to unbleached ones to speed the process. The sad likelyhood is that all the world’s corals are effectively what is known as zombie ecosystems to ecologists, still there, but doomed as surely as if there were the proverbial cartoon 16 tonne weight falling from above. Some depressed scientists are already referring to it as the reef’s terminal stage.LozImage credit: Ed Roberts/ARChttp://bit.ly/2ofJwFBhttp://bit.ly/2ofTV4hhttp://bit.ly/2nZ7SBS -- source link

More pics about