“…Over three decades of experiments and observations have developed and refined the central bleaching paradigm (e.g., Cziesielski et al, ) whereby accumulation of reactive oxygen species (ROS), and/or reactive nitrogen species (RNS), leads to signaling cascades and in turn expulsion or xenophagy of the algal endosymbionts (Family: Symbiodiniaceae) from the coral host (Davy et al, ; Smith et al, ; Tchernov et al, ; Weis, ). An overwhelming body of evidence has repeatedly demonstrated that perturbations to environmental factors underpinning optimum metabolic functioning can all result in bleaching; notably, temperature (Levin et al, ; Tchernov et al, ; Tolleter et al, ), light (Downs et al, ; Lesser & Farrell, ), salinity (Aquilar et al, 2019; Gardner et al, ; Ochsenkühn, Röthig, D'Angelo, Wiedenmann, & Voolstra, ) as well as inorganic nutrients including CO 2 (Anthony, Kline, Diaz‐Pulido, Dove, & Hoegh‐Guldberg, ; Crawley et al, ), iron and other trace metals (Biscéré, Ferrier‐Pagès, Gilbert, Pichler, & Houlbrèque, ; Ferrier‐Pagès et al, ; Shick et al, ), and the nitrogen‐to‐phosphate ratio (Fabricius, Cséke, Humphrey, & De'ath, ; Pogoreutz et al, ; Wiedenmann et al, ). Stability of the symbiosis rests on fine‐tuned resource exchange of primary metabolic currencies—C, N, P, electron carriers, etc.—among the algal symbionts, host, and/or broader associated microbiome (Suggett, Warner, & Leggat, ).…”