Scientists Fear The Worst As Surveys Start on Southern Section of the Great Barrier Reef
The big question of how the corals of the Great Barrier Reef survived the southern hemisphere's summer temperatures will be answered this week as a series of aerial survey's will be completed.
The world's largest barrier reef has already suffered its worst-ever recorded coral bleaching and subsequent mortalities in 2016 and 2017 with as much as half the corals killed.
A round of aerial surveys started on Monday (23 March) on the southern two-thirds of the reef. Surveys carried out on the northern section last week between the Torres Strait and Cairns on more than 500 reefs showed mixed results with outer reefs faring well but with some severe bleaching closer to shore.
But scientists fear the southern section may not have done as well as in previous years where it escaped most of the bleaching, as the highest water temperatures since 1900 have been recorded in the area this year - more than 1.5ºC up on normal. In previous years freak cloud cover protected the southern sections of the reef from the full impact of the summer temperatures.
The chief scientist at the Great Barrier Reef Marine Park Authority, Dave Wachenfeld, told Guardian Australia that whatever the survey concluded, the current bleaching should sound 'a very loud alarm bell' on the plight of the reef under global heating.
The authority said the full picture would only come clear once the aerial surveys were completed at the end of this week, and the data had been analysed.
Prof Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, spent 17 hours across four days in the air last week scoring bleaching on reefs with a staff member from the authority.
After completing the first four of nine days of aerial surveys, Hughes told Guardian Australia most of the severe bleaching had been seen at coastal reefs.
Townsville-based Dr William Skirving, of the US government’s Coral Reef Watch programme at the National Oceanic and Atmospheric Administration, said the agency’s initial research showed the heat stress in the south appears to have been localised but said the aerial surveys will reveal the full picture and extent of the bleaching.