Microbial communities of the deep seafloor sediment and manganese nodules from the Clarion-Clipperton Zone of the Eastern Pacific Ocean

Julia M. Otte, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany; Max Planck Institute for Marine Microbiology, Bremen, Germany
Julia M. Otte1,2, Massimiliano Molari2, Bathuan Cagri Yapan2, Jessica Volz3, Felix Janßen1,2, Frank Wenzhöfer1,2

(1) HGF MPG Group on Deep Sea Ecology and Technology, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Germany

(2) Max-Planck-Institute for Marine Microbiology, Germany

(3) Marine Geochemistry, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Germany

jotte@mpi-bremen.de, mamolari@mpi-bremen.de, byapan@mpi-bremen.de, jessica.volz@awi.de, fjanssen@mpi-bremen.de, fwenzhoe@mpi-bremen.de


Rising demand for minerals and metals is encouraging the search for alternative source in the oceans. Fields of deep-sea manganese (Mn) nodules attracted the attention for a long time because they contain important elements like nickel, copper, cobalt, manganese, iron, and rare earth elements. The environmental impacts of large-scale mining of Mn nodules are currently unknown. From February to May 2019 the Belgian and German licence area in the Clarion-Clipperton Zone (Eastern Pacific) were studied (Cruise SO268) to obtain baseline characteristics of the 4000 m deep Mn nodule fields. We aim to explore five main aspects: i) quantification of the present & active microbial and viral communities of bottom water, 5 m deep seafloor sediment, and ≤ 100 Mn nodules, ii) diversity and distribution of potential deep-sea cable bacteria and relevant metal-cycling microorganisms, iii) enrichment of potential Mn/Fe-cycling bacteria, iv) investigation of deep-sea microbial metabolisms by metagenomic/-transcriptomic, and v) quantification of microbial extracellular enzyme activity. In summary, our study helps to understand the composition of the microbial community and mediated biogeochemical processes in nodules fields and potential consequences associated with removal of nodules and resuspension of sediments. New regulations are required to protect these areas from irreversible anthropogenic impacts.