Most studies in the literature have focused on studying coral-microbe interactions at larger spatial scales

The gap

Evidence profile

Sourced from the future work and abstract of the source papers, classified as general, drawn from work published between 2025 and 2026, spanning 3 journals. Those papers have been cited 4 times in total.

Supporting evidence — 3 representative gaps

• Insights into the role of crustose coralline algae microbiomes on coral larval settlement in the Great Barrier Reef (2026) · Environmental Microbiome · doi

  Specific microorganisms associated with high or low larval settlement were identified for 14 different GBR coral species. These candidate inducers and inhibitors belonged to a diverse range of microbial taxa and repre- sent important targets for future research to distinguish the role of the algal host versus microbiome. Nonethe- less, further experimental validation will be needed to confirm the causality between these identified micro- organisms and settlement success. These taxa can be tested in validation experiments using isolated mono- or mixed-species biofilms or through manipulation of CCA microbiomes by enriching potential inducers or lowering inhibitor abundance. Building on these findings, we also suggest that future research focus on the functional char- acterisation of the CCA microbiome and the interactions with the CCA tissue-associated metabolomes to better interrogate whether common functions or biochemical pathways, rather than taxa, are the source of microbial settlement cues. While coral larvae are responding to different combinations of microbial taxa, these may rep- resent complementary functional pathways that trigger larval settlement. The identification of microbial induc- ers and inhibitors for larval settlement is critically impor- tant for our understanding of coral settlement behaviour, which would in turn inform recruitment and coral popu- lations dynamics as microbial communities shifts under anthropogenic stressors such as human-induced climate change [7, 108]. Furthermore, this study significantly adds to our knowledge and capability to guide the devel- opment of attractive substrates for coral larval settlement to optimise large-scale reef restoration. Turnlund et al. Environmental Microbiome (2026) 21:63 Supplementary Information The online version contains supplementary material available at h t t p s : / / d o i . o r g / 1 0 . 1 1 8 6 / s 4 0 7 9 3 - 0 2 6 - 0 0 9 0 7 - 6 . Supplementary Material 1. Supplementary Material 2.

  generalfuture work
  Keywords: settlement coral microbial larval taxa supplementary microbiome material associated identified different species inducers inhibitors future
• Nitrogen isotope ratios across the Bermuda coral reef: implications for coral nitrogen sources and the coral-bound nitrogen isotope proxy (2025) · Frontiers in Marine Science · cited 3× · doi

  Our N isotopic measurements of corals and other organisms and N pools across the Bermuda platform confirm a previously identified d15N increase toward the Bermuda coast and make use of that gradient to gain insights into the N sources of corals and the signals recorded by CS-d15N. The d15N of bulk coral tissue is consistent with corals feeding dominantly on some combination of zooplankton-sized organic matter and smaller PN. Depending on the relative importance of these two sources, the trophic d15N elevation of the corals is between 0 and 0.5-1.5‰. This range of values is well below the typical trophic d15N elevation of a heterotroph (of ~3-4‰; Post, 2002), consistent with the recycling and retention of low-d15N metabolic N by symbiont-bearing corals. Comparison of the coral data with d15N data from benthic macroalgae argues against corals’ significant reliance on the DIN. We consider these data as strong support for the dominance of coral feeding over DIN assimilation in this and other nutrient-poor reef settings, despite recent arguments to the contrary (Wiedenmann et al., 2023). In our view, these results conform with the adaptive benefits of the coral-zooxanthellae symbiosis. The coral host is a benthic animal typically occurring in sunlit and nutrient-depleted low latitude surface waters in which phytoplankton growth is limited by the “major” nutrients, nitrogen and phosphorus. Its feeding and metabolism naturally concentrate these nutrients within their tissues, as is true for all heterotrophic organisms, in which the net reaction is respiration. Mutual benefit can be found in harboring algal symbionts that use this concentrated stream of metabolically produced nutrients to fuel photosynthetic growth, with a portion of the resulting organic matter returning to the coral host. Thus, from the perspective of the coral host, their feeding provides chemical energy more than once, as the metabolic production of inorganic nutrients fuels symbiont growth. In contrast, dissolved inorganic nutrient uptake in nutrient-poor tropical and subtropical waters is challenging for phytoplankton, and it should be even more challenging for corals, in which the symbiont requiring these nutrients is isolated by multiple membranes, their own and their hosts, from the external nutrients. There are nutrient-rich surface waters over some coral reefs (e.g., those in the eastern equatorial Pacific as well as in human-impacted coastal regions), where DIN acquisition would be easier, and corals might assimilate DIN under these conditions. However, these environments are also often highly productive and characterized by relatively higher POM and zooplankton concentrations. Consequently, corals inhabiting these environments would have access to abundant organic nitrogen through feeding. In any case, we find the morphological and

  generalfuture work
  Keywords: corals coral nutrients feeding nutrient organic symbiont host waters growth organisms bermuda sources consistent zooplankton
• Heterotrophic feeding and symbiotic state shape the chemical microenvironment, microbiome composition, and activity in the coral gastrovascular cavity (2026) · Applied and Environmental Microbiology · cited 1× · doi

  However, most studies in the literature have focused on studying coral-microbe interactions at larger spatial scales, and especially the gastrovascular cavity (GVC) of corals remains underexplored despite its key role in coral processes, such as prey digestion, circulation of resources between polyps, sexual reproduction, and as the pathway for algal symbiont expulsion and colonization.

  generalabstractevidence 5/5
  Keywords: coral literature focused studying microbe interactions larger spatial scales especially gastrovascular cavity corals remains underexplored

Questions about this gap