SYDNEY, March 12 (Xinhua) -- Scientists in Australia have found that coral bleaching on the Great Barrier Reef is influenced not only by extreme summer heat, but also by winter conditions months earlier.
The study, published in Coral Reefs, shows sustained high winter temperatures worsen bleaching the following summer. In contrast, moderate levels of winter heat may actually reduce bleaching impacts, said a statement from Australia's James Cook University (JCU) on Wednesday.
"It's a Goldilocks range -- it's not too hot, not too cold, it's just right," said JCU Professor Scott Heron, who supervised the study.
"We think that corals living in these conditions might be better prepared for a stressful summer because they are exposed to a little bit of prior heat," Heron said.
Researchers explained that moderate winter heat can stimulate corals to produce heat-shock proteins, boosting cellular repair, metabolic activity, and shifting symbiotic algae to heat-tolerant types, while sustained high winter temperatures deplete energy reserves, damage tissues, and weaken symbiosis, increasing summer bleaching vulnerability.
The research analyzed bleaching observations and sea surface temperatures across the central Great Barrier Reef during the severe back-to-back bleaching events of 2016 and 2017.
The findings could enhance early-warning systems by incorporating pre-summer conditions into prediction models, the authors said. ■
