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@ARTICLE{Vuillemin:135226,
      author       = {Vuillemin, A. and Ariztegui, D. and Coninck, A. S. and
                      Lücke, A. and Mayr, C. and Schubert, C. J.},
      title        = {{O}rigin and significance of diagenetic concretions in
                      sediments of {L}aguna {P}otrok {A}ike, southern {A}rgentina},
      journal      = {Journal of paleolimnology},
      volume       = {50},
      number       = {3},
      issn         = {1573-0417},
      address      = {Dordrecht [u.a.]},
      publisher    = {Springer Science + Business Media B.V},
      reportid     = {FZJ-2013-03186},
      pages        = {275-291},
      year         = {2013},
      abstract     = {Authigenic minerals can form in the water column and
                      sediments of lakes, either abiotically or mediated by
                      biological activity. Such minerals have been used as
                      paleosalinity and paleoproductivity indicators and reflect
                      trophic state and early diagenetic conditions. They are also
                      considered potential indicators of past and perhaps ongoing
                      microbial activity within sediments. Authigenic concretions,
                      including vivianite, were described in late glacial
                      sediments of Laguna Potrok Aike, a maar lake in southernmost
                      Argentina. Occurrence of iron phosphate implies specific
                      phosphorus sorption behavior and a reducing environment,
                      with methane present. Because organic matter content in
                      these sediments was generally low during glacial times,
                      there must have been alternative sources of phosphorus and
                      biogenic methane. Identifying these sources can help define
                      past trophic state of the lake and diagenetic processes in
                      the sediments. We used scanning electron microscopy,
                      phosphorus speciation in bulk sediment, pore water analyses,
                      in situ ATP measurements, microbial cell counts, and
                      measurements of methane content and its carbon isotope
                      composition (δ13CCH4) to identify components of and
                      processes in the sediment. The multiple approaches indicated
                      that volcanic materials in the catchment are important
                      suppliers of iron, sulfur and phosphorus. These elements
                      influence primary productivity and play a role in microbial
                      metabolism during early diagenesis. Authigenic processes led
                      to the formation of pyrite framboids and revealed sulfate
                      reduction. Anaerobic oxidation of methane and shifts in pore
                      water ion concentration indicated microbial influence with
                      depth. This study documents the presence of active microbes
                      within the sediments and their relationship to changing
                      environmental conditions. It also illustrates the
                      substantial role played by microbes in the formation of
                      Laguna Potrok Aike concretions. Thus, authigenic minerals
                      can be used as biosignatures in these late Pleistocene maar
                      sediments.},
      cin          = {IBG-3},
      ddc          = {930},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {246 - Modelling and Monitoring Terrestrial Systems: Methods
                      and Technologies (POF2-246)},
      pid          = {G:(DE-HGF)POF2-246},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000324068900002},
      doi          = {10.1007/s10933-013-9723-9},
      url          = {https://juser.fz-juelich.de/record/135226},
}