Fog controls biological cycling of soil phosphorus in the Coastal Cordillera of the Atacama Desert

Author(s)

Xiaolei Sun, Wulf Amelung, Erwin Klumpp, Janek Walk, Ramona Mörchen, Christoph Böhm, Ghazal Moradi, Simon Matthias May, Federica Tamburini, Ye Wang, Roland Bol

Abstract

Soils in hyper-arid climates, such as the Chilean Atacama Desert, show indications of past and present forms of life despite extreme water limitations. We hypothesize that fog plays a key role in sustaining life. In particular, we assume that fog water is incorporated into soil nutrient cycles, with the inland limit of fog penetration corresponding to the threshold for biological cycling of soil phosphorus (P). We collected topsoil samples (0–10 cm) from each of 54 subsites, including sites in direct adjacency (<10 cm) and in 1 m distance to plants, along an aridity gradient across the Coastal Cordillera. Satellite-based fog detection revealed that Pacific fog penetrates up to 10 km inland, while inland sites at 10–23 km from the coast rely solely on sporadic rainfall for water supply. To assess biological P cycling we performed sequential P fractionation and determined oxygen isotope of HCl-extractable inorganic (Formula presented.). Total P (P

_t) concentration exponentially increased from 336 mg kg

⁻¹ to a maximum of 1021 mg kg

⁻¹ in inland areas ≥10 km. With increasing distance from the coast, soil (Formula presented.) values declined exponentially from 16.6‰ to a constant 9.9‰ for locations ≥10 km inland. Biological cycling of HCl-P

_i near the coast reached a maximum of 76%–100%, which could only be explained by the fact that fog water predominately drives biological P cycling. In inland regions, with minimal rainfall (<5 mm) as single water source, only 24 ± 14% of HCl-P

_i was biologically cycled. We conclude that biological P cycling in the hyper-arid Atacama Desert is not exclusively but mainly mediated by fog, which thus controls apatite dissolution rates and related occurrence and spread of microbial life in this extreme environment.

Organisation(s)

Department of Geography and Regional Research

External organisation(s)

Forschungszentrum Jülich, Rheinisch-Westfälische Technische Hochschule Aachen, Rheinische Friedrich-Wilhelms-Universität Bonn, Universität zu Köln, Eidgenössische Technische Hochschule Zürich, Bangor University

Journal

Global Change Biology

Volume

30

No. of pages

19

ISSN

1354-1013

DOI

https://doi.org/10.1111/gcb.17068

Publication date

01-2024

Peer reviewed

Yes

Austrian Fields of Science 2012

106058 Soil biology, 401902 Soil science

Keywords

ASJC Scopus subject areas

General Environmental Science, Global and Planetary Change, Ecology, Environmental Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/6597f45d-1591-4472-a343-2d063bc052e9