Biogeochemical investigation of sediments at the Hakon Mosby Mud Volcano (Barents Sea), supplement to: Lichtschlag, Anna; Felden, Janine; Brüchert, Volker; Boetius, Antje; de Beer, Dirk (2010): Geochemical processes and chemosynthetic primary production in different thiotrophic mats of the Hakon Mosby Mud Volcano (Barents Sea). Limnology and Oceanography, 55(2), 931-949

• Main Authors: Lichtschlag, Anna, Felden, Janine, Brüchert, Volker, Boetius, Antje, de Beer, Dirk
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2009
• Subjects: Push corer; Microsensor profiler; MultiCorer; VICKING; Pourquoi Pas ? 2005; Hotspot Ecosystem Research on the Margins of European Seas HERMES; Barents Sea; Pourquoi Pas; Pourquoi-Pas; Pourquoi-Pas?
• Online Access: https://dx.doi.org/10.1594/pangaea.715022; https://doi.pangaea.de/10.1594/PANGAEA.715022

We have investigated if in a cold seep methane or sulfide is used for chemosynthetic primary production and if significant amounts of the sulfide produced by anaerobic oxidation of methane are oxidized geochemically and hence are not available for chemosynthetic production. Geochemically controlled redox reactions and biological turnover were compared in different habitats of the Håkon Mosby Mud Volcano. The center of the mud volcano is characterized by the highest fluid flow, and most primary production by the microbial community depends on oxidation of methane. The small amount of sulfide produced is oxidized geochemically with oxygen or is precipitated with dissolved iron. In the medium flow peripheral Beggiatoa habitat sulfide is largely oxidized biologically. The oxygen and nitrate supply is high enough that Beggiatoa can oxidize the sulfide completely, and chemical sulfide oxidation or precipitation is not important. An internally stored nitrate reservoir with average concentrations of 110 mmol L-1 enables the Beggiatoa to oxidize sulfide anaerobically. The pH profile indicates sequential sulfide oxidation with elemental sulfur as intermediate. Gray thiotrophic mats associated with perturbed sediments showed a high heterogeneity in sulfate turnover and high sulfide fluxes, balanced by the opposing oxygen and nitrate fluxes so that biological oxidation dominates over geochemical sulfide removal processes. The three habitats indicate substantial small-scale variability in carbon fixation pathways either through direct biological use of methane or through indirect carbon fixation of methane-derived carbon dioxide by chemolithotrophic sulfide oxidation.