Managing and manipulating coral microbes for coral health under climate change

Despite the early coral reef bleaching warning system (NOAA/USA), there is no feasible treatment option that can minimize temperature bleaching and/or disease impacts on corals in the field at reef scale. I here present the... [ view full abstract ]

Despite the early coral reef bleaching warning system (NOAA/USA), there is no feasible treatment option that can minimize temperature bleaching and/or disease impacts on corals in the field at reef scale. I here present the first attempts to extrapolate the widespread and well established use of bacterial consortia to protect or improve health in other organisms (e.g., humans and plants) to corals. The results from a controlled and replicated aquarium experiment demonstrated the ability of a selected putative beneficial microorganisms for corals (pBMC) consortium to delay coral bleaching induced through both temperature and pathogen challenge. The improvements in coral bleaching metrics were observed in pBMC inoculated corals, even when also challenged with V. coralliilyticus, at 30^°C, in contrast to controls without pBMC addition, which displayed strong bleaching signs as indicated by significantly lower photopigments and F_v/F_m ratios. Differences in the coral microbiome community structures were also observed between treatments with and without pBMC addition with specific bacterial groups correlated with bleached and non-bleached corals. Delaying the effects of bleaching might buy time for the corals allowing for dissipation of the stress, thereby reducing levels of mortality across the duration of a bleaching event. Strategies currently used for the remediation of oil spills could be adapted for the delivery of coral "probiotics". In addition, the development of protective management or treatments to boost the resilience of native and diverse populations of corals in the field can also represent a useful and complementary strategy to be applied in restoration efforts.