āDestructiveā marine heatwaves driving loss of microalgae that feed coral, says Global Coral Reef Monitoring Network Caribbean reefs have half as much hard coral now as they did in 1980, a study has found.The 48% decrease in coral cover has been driven by climate breakdown, specifically marine heatwaves. They affect the microalgae that feed coral, making them toxic and forcing the coral to expel them. Continue readingā¦