Encyclopedia of Astrobiology

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


  • Daniele L. Pinti
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_5157-2


The chemocline is the vertical chemical gradient (cline) which is produced in a mass of water having restricted circulation (for example, deep lakes). The local conditions favor the formation of bottom anoxic waters, where only anaerobic forms of life exist, overlain by oxygenated waters, where aerobic photosynthetic life flourishes. At the contact between these two zones, photosynthetic communities of anaerobic purple sulfur bacteria develop, taking advantage of both the sunlight from above and the hydrogen sulfide (H2S) produced below. In astrobiology, this zone of the chemocline is studied because it could be an analog of Archean niches of life where limited oxygenated waters developed over an anoxic Archean ocean.

See Also


Local Condition Bioorganic Chemistry Hydrogen Sulfide Deep Lake Chemical Gradient 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.GEOTOP Research Center for Geochemistry and GeodynamicsUniversité du Québec à MontréalMontréalCanada