New research led by a team from the Australian Institute of Marine Science (AIMS) has uncovered a complex picture of both loss and gain within the microalgal communities of corals after the 2016 Great Barrier Reef mass coral bleaching.
Comparing the effects of accumulated heat stress across more than 1,600 symbiotic microalgal communities of corals before and after the 2016 event, the scientists found the diversity present within the environment greatly increased following mass bleaching. They also found the diversity of more heat resistant microalgal types increased in one of the three coral species studied.
Co-author Dr. Patrick Laffy said it was important to understand how individual corals can modify their symbiont composition in bleaching events. “We found the heat-tolerant microalgae Durusdinium increased in abundance in the coral species Acropora millepora after bleaching, but this trend was not observed in the two other Acropora species. After bleaching, we also discovered the overall diversity of algal symbionts in some of the coral species had reduced. This new balance can have mixed consequences for how coral species grow and survive”.