Fig. 2

Potential of reef seawater microbes to inform on reef health status. Successful reef management interventions need to rely on acute and early identification of changes in the reef, before ecosystem ‘tipping points’ are reached (A). However, most reef monitoring programs are based on visual signs to assess ecosystem stress (e.g., coral disease, bleaching and community-level shifts), which become evident only after prolonged environmental disturbances (B). Due to their short generation times, seawater microbes respond rapidly to environmental changes, and it has therefore been well established that marine bacterioplankton allows accurate and early diagnostics of environmental fluctuations in the reef (C, middle). However, the predictive potential of the seawater microbiome has been largely unexplored and it remains unclear how environmental changes will alter microbial functioning of reef bacterioplankton, and how this may translate to reef ecosystem functioning via cascading effects and feedback loops (C, middle). Figure 2C was adjusted from Vanwonterghem and Webster [18] with permission from authors