Microbial life in an ultra-deep sulfate-methane transition zone on the Antarctic continental margin ...

• Main Authors: Bauersachs, Thorsten, Kallmeyer, Jens, Jia, Zeyu, Schmidt, Mark, Schwark, Lorenz
• Format: Text
• Language: English
• Published: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV) 2023
• Subjects: Amundsen Sea; Antarctic; The Antarctic; West Antarctic Ice Sheet; Antarc*; Ice Sheet
• Online Access: https://dx.doi.org/10.48380/9mkf-t160; https://www.dggv.de/e-publikationen/microbial-life-in-an-ultra-deep-sulfate-methane-transition-zone-on-the-antarctic-continental-margin

Ocean sediments are considered to contain microbial biomass that equals the stock of organic matter on all the continents combined. Knowledge on the spatiotemporal distribution and abundance of microbial life in marine subsurface sediments, however, is still sparse. A region particularly understudied in this respect is the Antarctic continental margin, in which the deep biosphere is largely terra incognita . A 794 m-long sediment sequence (Site U1532), recovered during IODP Expedition 379: “Amundsen Sea West Antarctic Ice Sheet History” provides the unique opportunity to study the composition and abundance of the deep biosphere in polar regions of the Southern Hemisphere. Porewater profiles of sulfate and methane concentrations indicate that the sulfate-methane transition zone (SMTZ) is located at a depth of ~660 mbsf, making it one of the deepest SMTZ ever encountered. Stable carbon isotope measurements attest to the biological origin of the methane and provide direct evidence for an active deep-dwelling ...