Community Composition and Metabolic Diversity of Deep-sea Lophelia pertusa Microbiomes and their Relatedness to the Local Environment

Shallow water corals host complex communities of diverse microorganisms; however, studies have only begun to characterize the microbial communities associated with deep-sea corals. Determining the source of the microorganisms in coral tissue and/or skeleton may aid in defining their biological role in Lophelia pertusa. This study was conducted to evaluate similarities between L. pertusa-associated microbial communities and those in the immediate, surrounding environment. Filtered seawater, sediment, and L. pertusa samples were collected from two deep-water shipwrecks in the northern Gulf of Mexico. Individual coral polyps (n = 6 per colony) were removed and subjected to two DNA extraction techniques (whole polyp crushing or tissue removal from skeleton), and genomic bacterial DNA from samples was amplified and sequenced. Comparison between coral sample extracts may aid in elucidating in which part of the coral (tissues, skeleton, or both) specific microorganisms are located, and their potential functional roles in the coral host. Biological and metabolic diversity of associated microorganisms were characterized and statistical analyses were carried out to test for differences in bacterial communities between sample types and geographic locations, and a Bayesian approach was used to evaluate the sources of bacteria to coral tissue from the surrounding environment. This study may help explain the features that shape L. pertusa microbiomes and provide insight into how local environmental disturbances in deep benthic habitats may impact deep sea corals.