Yes algae is taking over the oceans..the excessive carbon in the atmosphere is being converted to algae blooms throughout the ocean. It's the earth's way of cleansing itself and is an argument against whether the earth is unaturally heating.
Incidents like these occur constantly...even though this reef has never been touched, others have even before industrialization. The current weather cycle is the catalyst with these increased water temps. The same patterns that are causing catastrophic hurricanes in the gulf and carib are the culprit here. Does global warming amplify the effect??? IMO yes, however, science has yet to fully substantiate this theory.
There are other factors outside of global warming which are contributring to the proliferation and acceleration of reef degradation. It will be a culmination of all of these factors that lead to the decimation of the majority of the world's reefs. Not just global warming...