Universität zu Köln

Wang, Ye, Moradi, Ghazal, Klumpp, Erwin ORCID: 0000-0002-4810-9414, von Sperber, Christian, Tamburini, Federica, Ritter, Benedikt ORCID: 0000-0002-5652-1169, Fuentes, Barbara, Amelung, Wulf ORCID: 0000-0002-4920-4667 and Bol, Roland (2021). Phosphate oxygen isotope fingerprints of past biological activity in the Atacama Desert. Geochim. Cosmochim. Acta, 311. S. 1 - 12. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1872-9533

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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 (delta(OHHCl-P)-O-18) 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 delta(OHHCl-P)-O-18 values were constant with depth and deviated from biologically-driven isotopic equilibrium. In contrast, we observed a considerable increase of delta(OHHCl-P)-O-18 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 delta(OHHCl-P)-O-18 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. (C) 2021 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wang, Ye UNSPECIFIED UNSPECIFIED UNSPECIFIED Moradi, Ghazal UNSPECIFIED UNSPECIFIED UNSPECIFIED Klumpp, Erwin UNSPECIFIED orcid.org/0000-0002-4810-9414 UNSPECIFIED von Sperber, Christian UNSPECIFIED UNSPECIFIED UNSPECIFIED Tamburini, Federica UNSPECIFIED UNSPECIFIED UNSPECIFIED Ritter, Benedikt UNSPECIFIED orcid.org/0000-0002-5652-1169 UNSPECIFIED Fuentes, Barbara UNSPECIFIED UNSPECIFIED UNSPECIFIED Amelung, Wulf UNSPECIFIED orcid.org/0000-0002-4920-4667 UNSPECIFIED Bol, Roland UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-596889
DOI:	10.1016/j.gca.2021.07.027
Journal or Publication Title:	Geochim. Cosmochim. Acta
Volume:	311
Page Range:	S. 1 - 12
Date:	2021
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1872-9533
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MICROBIAL COMMUNITIES; SOIL-PHOSPHORUS; NORTHERN CHILE; CLIMATE-CHANGE; ALLUVIAL-FAN; MIOCENE AGE; WATER; ARIDITY; PHOSPHOMONOESTERASES; FRACTIONATION Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59688