PRJNA540908
Environmental DNA metabarcoding of hydrothermal vent sediment
Deep ocean hydrothermal vent ecosystems face physical disturbances from natural tectonic activities and are at increasing risk of mineral resource exploitation, raising concerns about the resilience of endemic biological communities. Following destructive events, efficient and rapidly applicable surveys of organisms are required to monitor a possible return of communities to baseline status. In the present study, we tracked the passive recolonization of benthic metazoan communities living on the Montségur edifice within the Lucky Strike vent field (Mid-Atlantic Ridge), after an induced disturbance. Sediment samples were collected during the disturbance and one year later, for environmental DNA (eDNA) screening using metabarcoding of four genetic markers, including mitochondrial gene Cytochrome Oxidase I (COI) and nuclear 18S ribosomal RNA, V1V2 region (18S-V1V2). Informatic evaluation of the environmental datasets allowed us to examine the influence of time, predator presence and habitat types (active vent, periphery and inactive) on the community recolonization efforts. We also generated a DNA barcoding inventory consisting of taxa collected from Montségur, whose genetic information was used for taxonomic assignment of the eDNA datasets. The marker dataset produced a maximum of 560 OTUs, which included species common to Lucky Strike such as Bathymodiolus azoricus, Amphisamytha lutzi, Lepetodrilus atlanticus and Protolira valvatoides, as well as less common taxa. Baseline data collected at the start of the experiment identified higher species richness at sites peripheric to the active edifice, as well as inactive sites farther off. Taxonomic compositions of biological communities were found to be dissimilar among the habitats in relation to differing environmental conditions. One year following the initial disturbance, analysis of recolonization data found no statistical difference from baseline communities, nor communities with or without the cages used to limit access to predators. Our technical protocols provide a reproducible and sensitive strategy for improved understanding of the biotic and abiotic variables influencing benthic habitat restoration at Lucky Strike. Continued monitoring of these sites is currently ongoing, with the purpose of informing conservation and management decisions relating to the protection of hydrothermal vent ecosystems.