Mass coral bleaching of P. versipora in Sydney Harbour driven by the 2015–2016 heatwave

摘要: High-latitude coral communities are distinct from their tropical counterparts, and how they respond to recent heat wave events that have decimated reefs remains unknown. In Australia, the 2016 El Nino resulted in the largest global mass bleaching event date, reaching as far south as Sydney Harbour (~ 34°S). Coral was observed for first time (affecting ca., 60% of all corals) sea surface temperatures in remained > 2 °C above long-term mean summer maxima, enabling us examine whether high-latitude corals bleached a manner described corals. Responses the geographically cosmopolitan Plesiastrea versipora southerly restricted Coscinaraea mcneilli were contrasted across two harbour sites, both situ among samples-maintained ex aquaria continually supplied with seawater. While taxa hosted same species microalgal endosymbiont (Breviolum spp; formerly clade B), only P. bleached both via pronounced losses cells. Both displayed very different metabolic responses (growth, photosynthesis, respiration calcification) susceptibilities under elevated temperatures. Bacterial microbiome profiling, however, revealed convergence bacterial community composition throughout bleaching. Corals found temperate regions, including generalist versipora, will therefore likely be highly susceptible future change waves grow frequency severity unless thermal thresholds increase. Our observations provide further evidence systems reorganisation climate change.