Limitations of microbial hydrocarbon degradation at the Amon Mud Volcano (Nile Deep Sea Fan), supplement to: Felden, Janine; Lichtschlag, Anna; Wenzhöfer, Frank; de Beer, Dirk; Feseker, Tomas; Pop Ristova, Petra; de Lange, Gert J; Boetius, Antje (2013): Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan). Biogeosciences, 10, 3269-3283

DOI

The Amon mud volcano (MV), located at 1250 m water depth on the Nile Deep Sea Fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulphate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition and microbial activities over three years, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulphide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. Furthermore, within three years, cell numbers and hydrocarbon degrading activity increased at the gas-seeping sites. The low microbial activity in the hydrocarbon-vented areas of Amon mud volcano is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer mud volcano area is limited by hydrocarbon transport.

Identifier
DOI https://doi.org/10.1594/PANGAEA.804779
Related Identifier https://doi.org/10.5194/bg-10-3269-2013
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.804779
Provenance
Creator Felden, Janine; Lichtschlag, Anna; Wenzhöfer, Frank; de Beer, Dirk; Feseker, Tomas; Pop Ristova, Petra; de Lange, Gert J; Boetius, Antje
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2013
Funding Reference Sixth Framework Programme; Seventh Framework Programme
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Representation
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 58 datasets
Discipline Earth System Research
Spatial Coverage (31.541W, 32.357S, 31.711E, 32.370N)
Temporal Coverage Begin 2006-10-24T04:58:00Z
Temporal Coverage End 2009-11-13T15:22:27Z