This article total and utter scaremongering nonsense. The Australian Government has split the 2300 km long Great Barrier Reef into 4 sections. The most northerly one has been stressed by one or more factors that might possibly include increased sea temperature. The two most southerly sections are seen as healthy and growing.
http://www.gbrmpa.gov.au/media-room/coral-bleaching
What did they use: Controlled nuclear detonations?
Regards,