Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to prokaryotes such as bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon...

Anoxic nitrification in marine sediments

Nitrate peaks are found in pore-water profiles in marine sediments at depths considerably below the conventional zone of oxic nitrification. These have been interpreted to represent nonsteady-state effects produced by the activity of nitrifying bacteria, and suggest that nitrification occurs throughout the anoxic sediment region. In this study, ΣNO3 peaks and molecular analysis of DNA and RNA e...

Uranium(IV) adsorption by natural organic matter in anoxic sediments.

Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV...

Silicate weathering in anoxic marine sediments

K. WALLMANN*, G. ALOISI, M. HAECKEL, P. TISHCHENKO, G. PAVLOVA, J. GREINERT, S. KUTTEROLF AND A. EISENHAUER 1 IFM-GEOMAR Leibniz Institute of Marine Sciences, Wischhofstrasse 1-3, 24148 Kiel, Germany 2 Laboratoire de Paléoenvironnements et Paléobiosphère, Université Claude Bernard Lyon I, 2, rue Dubois, F69622 Villeurbanne cedex, France 3 Pacific Oceanological Institute (POI), 43, Baltiyskaya S...

DyNAMICS AbOvE AND WIthIN PErMEAbLE SEDIMENtS