Warmer seas are turning Great Barrier Reef turtles female, a study has found A section of highway connecting Sydney and Melbourne started to melt. Bats fell dead from the trees, struck down by the heat. On the northern Great Barrier Reef, 99% of baby green sea turtles, a species whose sex is determined by temperature, were found to be female. In outer suburban Sydney, the heat hit 47.3C (117F) bef