This Year's Bleaching Event Biggest Ever For GBR; Extends 2,000 Kilometers; 3rd Bleaching In 5 Years
When Terry Hughes peered through the window of a small plane gliding over the Great Barrier Reef in Australia, what he saw troubled him greatly. Instead of healthy reef systems, there was mile upon mile of bleached white coral. “It’s very confronting to see the scale of the bleaching, and to know that you’re going to lose a lot of corals on the heavily bleached reefs,” Hughes, a professor and director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, told Mongabay.
This year, the Great Barrier Reef — the world’s largest reef system, spanning more than 344,400 square kilometers (133,000 square miles) — suffered its third major bleaching event in the last five years. Previous ones took place in 2016 and 2017, with the 2016 event considered the most severe. However, this year’s bleaching is proving to be the most extensive, Hughes said. “We have coastal bleaching this year all the way along the Great Barrier Reef — from the Torres Straits in the north to the southern boundary of the marine park near Bundaberg,” Hughes said. “That’s a distance of more than 2,000 kilometers,” or about 1,250 miles.
Warming water temperatures, induced by climate change, are to blame for this year’s bleaching. The Australian Bureau of Meteorology (BOM) recorded its highest ever sea temperature on the Great Barrier Reef in February.
While 40% of the reef remained untouched, 25% experienced severe bleaching, and 35% was moderately bleached. The southern section of the Great Barrier Reef, which stayed mostly intact during the events of 2016 and 2017, got hit very hard this year.
A map showing which areas were severely bleached, and which remained untouched. Image by ARC Centre of Excellence for Coral Reef Studies.
EDIT
https://news.mongabay.com/2020/04/great-barrier-reef-suffers-biggest-bleaching-event-yet/
