Enhancing the Blue Economy through Metagenomic Characterization of Hydrothermal Vent and Methane Seep Communities
Hydrothermal vents and hydrocarbon seeps along U.S. continental margins are slated to become a key component of the "blue economy" due to the potential of recovering their oil and gas reserves and their unique chemosynthetic biological communities, which enhance fisheries resources and hold pharmaceutical promise. Vents often house abundant precious metals (e.g., silver, gold, copper, manganese, cobalt, zinc), which are in high demand as electronics components and whose availability on land is dwindling, raising interest in international deep-sea mining. Several countries have invested in specialized deep-sea mining equipment and are gearing towards large-scale deployment; the U.S. is behind. Ecological risks to vent and methane seep communities are escalating due to this increased mining, oil and gas drilling, and bottom trawl fishing. The PMEL 'Omics Program currently employs new metagenomic biotechnology to help characterize these unique biological communities, whose species compositions, population relationships, and connectivity and exchanges with nearby communities are poorly understood.
This research is important to NOAA due to the high economic potential of vents and seeps, meeting the NOAA Research (OAR) and NOAA Ocean Exploration Program (OE) missions to explore, conserve, and manage our ocean's natural resources. The work specifically addresses critical knowledge gaps to discover, identify, and describe the unique biological assemblages of vents and seeps and discern their inter-connectivity relationships, including those with biopharmaceutical, biotechnical, and fishery potential, acquiring baseline ocean environmental information to help inform decision-making about exploitation of their resources. Several hundred hydrothermal vent fields and seeps have been discovered, with hundreds more predicted, including abundant seeps off the Cascadia margin. Yet, their biological communities are underexplored and understudied, and many vents and seeps remain undiscovered. Furthermore, we have limited knowledge about how to ensure that our vent and seep resources are used sustainably as the mining, drilling, and trawling industries likely grow.
The specific research aims are to develop and apply new, cutting edge metagenomics to (1) identify and quantify the living communities of fishes, invertebrates, and microbes to species and population levels, in relation to their physical and chemical oceanic parameters, and (2) analyze their connectivity, relationships, and exchanges, horizontally and vertically, with surrounding ecosystems. Metagenomics harnesses the power of targeted high throughput sequencing (HTS) assays to rapidly and simultaneously sequence billions of environmental (e)DNA fragments and eRNA (indicating metabolic activity) shed by entire communities of living organisms (in their mucus, cells, waste products, etc.) into water. The water is collected remotely using CTD Niskin bottles and/or ROVs at vent and seep sites. Targeted metabarcoding assays designed for multiple genes and gene regions are used to identify many microbes, invertebrates, and fishes to either species or nearest operational taxonomic unit (OTU) and some to site-specific population. In addition, for two select key taxa, tissue samples will be used to explore using RADSeq (Restriction site Associated DNA Sequencing) and mitogenome sequencing to assess their genetic and genomic variability, as well as connectivity among populations. This collective approach aims to provide much greater efficiency in both time and cost, as well as information, than traditional video surveys and morphological analysis of specimens.
We are presently collaborating with several research expeditions in the Pacific, and as a result participated in both the 2021 West Coast Ocean Acidification Cruise and the 2021 E/V Nautilus's Cascadia Margin Seep Exploration. Further research at the Axial Seamounts in continuation of work completed in Summer 2020 is planned for Summer 2022.