Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Oxic Sediments

  • Rosalie TostevinEmail author
  • Simon W. Poulton
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_5414-1

Definition

Pore waters within oxic sediments contain measureable amounts of dissolved oxygen. In general, pore water oxygen concentrations decline with depth due to organic matter degradation. The depth of oxygen penetration varies depending on the sedimentation rate, mixing processes, the flux and type of organic carbon, and the oxygen content of bottom waters.

Overview

Sediments at the seafloor are porous and poorly consolidated and thus readily allow diffusion of bottom waters and the dissolved gases that they contain into the sediment. With depth, sediments undergo compaction and eventually lose contact with overlying seawater. While sediment pore waters at or close to the sediment-water interface in the global ocean commonly contain dissolved oxygen, the concentration of oxygen declines with depth due to organic matter degradation.

Deposited organic matter is degraded at the seafloor and during burial in the sediments, with less than 1% surviving to become part of the rock record...

Keywords

Oxygen Redox Diagenesis Organic carbon Microbes Respiration Pore waters 
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References and Further Reading

  1. Bender ML, Heggie DT (1984) Fate of organic carbon reaching the deep sea floor: a status report. Geochim Cosmochim Acta 48:977–986ADSCrossRefGoogle Scholar
  2. Emerson S, Hedges J (1988) Processes controlling the organic carbon content of open ocean sediments. Paleoceanography 3:621–634ADSCrossRefGoogle Scholar
  3. Kristensen E (2000) Organic matter diagenesis at the oxic/anoxic interface in coastal marine sediments, with emphasis on the role of burrowing animals. In: Liebezeit G, Dittmann S, Kröncke I (eds) Life at interfaces and under extreme conditions, developments in hydrobiology. Springer, Dordrecht, pp 1–24Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2020

Authors and Affiliations

  1. 1.Department of Geological SciencesUniversity of Cape TownRondeboschSouth Africa
  2. 2.School of Earth and EnvironmentUniversity of LeedsLeedsUK