% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Wang:903159,
      author       = {Wang, Ye and Moradi, Ghazal and Klumpp, Erwin and von
                      Sperber, Christian and Tamburini, Federica and Ritter,
                      Benedikt and Fuentes, Barbara and Amelung, Wulf and Bol,
                      Roland},
      title        = {{P}hosphate oxygen isotope fingerprints of past biological
                      activity in the {A}tacama {D}esert},
      journal      = {Geochimica et cosmochimica acta},
      volume       = {311},
      issn         = {0016-7037},
      address      = {New York, NY [u.a.]},
      publisher    = {Elsevier},
      reportid     = {FZJ-2021-04882},
      pages        = {1 - 11},
      year         = {2021},
      abstract     = {The Atacama Desert (Chile) is one of driest places on
                      Earth, with a hyper-arid climate and less than 2 mm yr−1
                      precipitation; nevertheless, it has experienced rare periods
                      of sporadic rainfall. These periods shortly enhanced
                      vegetation growth and microbial activity, which must have
                      utilized major nutrients such as phosphorus (P). However,
                      any biological cycling of P involves an oxygen exchange with
                      water, which should now reside in the hyperarid soils as
                      tracer of life. In order to identify such evidences, we
                      performed sequential P fractionation and analyzed the oxygen
                      isotope composition of HCl-extractable phosphate
                      (δ18OHCl–P) in the surface soil (0–15 cm) of a climatic
                      gradient along the rising alluvial fans of the Central
                      Depression to the Precordillera, Chile. At the driest sites,
                      the δ18OHCl-P values were constant with depth and deviated
                      from biologically-driven isotopic equilibrium. In contrast,
                      we observed a considerable increase of δ18OHCl-P values
                      below the soil surface at less arid sites, where some
                      isotope values were even within the range of full isotopic
                      equilibrium with biologically cycled phosphate. For the
                      latter sites, this points to most efficient biological P
                      cycling right below the uppermost surface of the desert.
                      Critically, the absolute concentrations of this biologically
                      cycled P exceeded those of P potentially stored in living
                      microbial cells by at least two orders of magnitude.
                      Therefore, our data provides evidence that δ18OHCl-P values
                      trace not recent but past biological activity, making it a
                      powerful tool for assessing the existence, pathways and
                      evolution of life in such arid ecosystems on Earth and,
                      thus, potentially on other planets such as Mars.},
      cin          = {IBG-3},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217)},
      pid          = {G:(DE-HGF)POF4-2173},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000693337600001},
      doi          = {10.1016/j.gca.2021.07.027},
      url          = {https://juser.fz-juelich.de/record/903159},
}