Landscape approach to evaluating microbial genetic resources associated with seafloor massive sulphide deposits

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Microbes are often overlooked in environmental impact assessments despite their critical role in ecosystem function and mostly unexplored potential as a source of genetic novelty for pharmaceutical and biotechnological applications. Funds are requested to pioneer landscape-scale evaluations of the genetic resource potential of microbes associated with seafloor massive sulphide (SMS) deposits in the deep ocean. Results will help build a broader view of the environmental and societal consequences of deep-sea mining. The current debate opposes mining interests against the legitimate concerns of biodiversity conservation that mostly focus on benthic fauna. Our research will inform discussions that weigh the value to society of the potential microbial genetic resources associated with SMS deposits, against the market value of the contained metals. SMS deposits, which have horizontal dimensions of 10s to 100s of metres, are formed by the precipitation of sulphide minerals at seafloor hydrothermal vents, and occur in association with seafloor volcanism on mid-ocean ridges. These deposits host a hitherto unquantified diversity of microorganisms, many of them extremophiles, many certainly unique, that are of high potential interest for the biotechnology and pharmaceutical sectors. Microbial diversity and novelty at active vents vary with habitat conditions such as temperature and rates of fluid discharge. When hydrothermally activity ceases, the deposited minerals themselves become the chemosynthetic energy source for microbial growth. Microbes colonizing inactive and weathering SMS deposits are less studied but appear taxonomically distinct from those at active vents and the surrounding deep sea, and may represent a separate genetic resource. Inactive deposits are the favoured target for future mining operations. Single purpose exploitation of SMS deposits for their metals would severely impact or even eliminate associated genetic resources. We will combine microbial biodiversity surveys, metagenomics and genome mining, with 3D modelling and geospatial mapping to develop quantitative, landscape-scale assessments of the genetic resource potential of entire SMS deposits. We will begin by using results of meta-barcoding (16S rRNA genes) for an initial assessment of the taxonomic diversity and novelty of samples collected from individual SMS deposits. We will then use genome mining tools to document the novelty of reconstructed microbial genomes from these deposits, and then evaluate the number and novelty of biosynthetic gene clusters (BGCs) at each site. BGCs encode the biosynthetic assembly of secondary metabolites that often have anti-microbial and anti-tumour properties, of great interest to the pharmaceutical industry.  Understanding relationships between 'biosprospecting metrics' and habitat types will enable future researchers and environmental managers to use habitat maps to evaluate the genetic resource potential of entire SMS deposits.