Upper-mesophotic and shallow reef corals exhibit similar thermal tolerance, sensitivity and optima

The physiology of ectotherms living in marine environments is strongly influenced by their local thermal experience. Scleractinian corals near optimums are increasingly vulnerable to bleaching and mortality as oceanic heat waves increase globally. Mesophotic coral ecosystems (MCEs) below 30 m depths characteristically cooler than adjacent shallow water reefs, which according theory should result differential metabolic responses temperature between depths. How temperatures influence physiological mesophotic poorly understood. We compared sensitivities four species a (5–10 m) upper-mesophotic (30?35 reef Bermuda. Thermal performance curves (TPC) were measured laboratory mesocosms for common (Diploria labyrinthiformis, Orbicella franksi, Montastraea cavernosa Porites astreoides) across wide range (19?36). Our results indicate that the maximum rate gross photosynthetic (GP) (GP-Pmax) mean overall rates (GP-lnc) varied significantly among species. In contrast, sensitivity (Pmax, Topt, lnc, E, Eh, or Th) did not vary conspecifics except deactivation energy (GP-Eh) D. labyrinthiformis. Additionally, respiration (R) differ any metric. Similar suggest adaptation and/or acclimatization different conditions likely occurring. Instead, Bermuda do have lower thresholds conspecifics, but similar supporting potential MCEs function refuge.