Variation in phenotype and microbiome of three widespread Caribbean corals between mangrove and reef habitats
OA Version
Citation
Abstract
Coral reef ecosystems are increasingly threatened by anthropogenic forces, especially climate change. However, many reef corals also occur in mangrove habitats. For example, in the Caribbean, roughly half of the ~75 coral species found on reefs also inhabit mangroves. The ability to inhabit both reefs and mangroves may promote the survival of these generalist corals, but environmental conditions are quite different on reefs and mangroves, challenging corals to adopt different phenotypes and perhaps assemble distinctive microbiomes in order to survive in different habitats. In Belize’s Turneffe Atoll Marine Reserve, mangrove corals have been found to experience significantly lower light levels, higher peak temperatures, and greater temperature variability than conspecifics living in lagoonal patch reefs. Significant differences in colony morphology, color and corallite dimensions were also found across habitats. To understand whether the differences in phenotype of the same coral species from both habitats were plastic or fixed, fragments of the club finger coral, Porites porites, were subjected to reciprocal transplantation between reef and mangrove habitats. Corallite morphological differences on the transplant samples between two habitats were examined, measuring corallite area, spacing, and density. Regardless of their native habitat (reef or mangrove), corals transplanted to the reef exhibited greater corallite density, smaller corallite area, and reduced corallite spacing. When transplanted to the same habitat, mangrove-sourced corals exhibited greater corallite density, as well as smaller corallite area, and reduced corallite spacing. To understand how the microbiome varies in corals living across habitats, metagenomic approaches were used to compare the bacterial, archaeal, and eukaryotic photosynthetic components of the holobiont in two widespread corals — Porites astreoides and Siderastrea siderea — across mangrove and lagoon habitats. Indicator species analyses revealed many significant bacteria, archaea, and photosynthetic eukaryotes that differed significantly among the four species-by-habitat combinations. Understanding what corallite morphological traits and microbiome components of the corals surviving in mangrove habitats could offer insight into promoting these traits and components and increasing chances of survival in harsh environments for corals in peril.
Description
2024