The microbial and geochemical architecture of Scotian Slope cold seep Site 2A-1, Scotian Slope, Canada

Abstract

Cold seeps occur globally along the seabed of continental margins, expelling reduced fluids, which help to form oasis-like ecosystems in highly redox stratified sediments. In this study, a 600 m long, six push core, transect was collected from cold seep site 2A-1, located on the Scotian Slope of Eastern Canada. Downcore porewater ions and lipidomic profiles were generated. These data were compiled as spatially resolved, two-dimensional heatmaps to examine both vertical and lateral changes in the subsurface geochemical and microbiological architecture. Twenty-three lipid classes, predominantly of archaeal origin, were tentatively identified and quantified. Microbially mediated metabolic zones of targeted processes, were mapped based on ion porewater concentrations, diffusion fluxes, carbon isotope values, lipidomic diversity patters, and biomarker proxy data. The resolved lipidome indicates a zoned archaeal community with diversity increasing as a function of seepage rate that provides insights into the seep’s formation and microbial dynamics.