The weathering front is the boundary beneath Earth's surface where pristine rock is converted into weathered rock. It is the base of the "critical zone", in which the lithosphere, biosphere, and atmosphere interact. Typically, this front is located no more than 20 m deep in granitoid rock in humid climate zones. Its depth and the degree of rock weathering are commonly linked to oxygen transport and fluid flow. By drilling into fractured igneous rock in the semi-arid climate zone of the Coastal Cordillera in Chile we found multiple weathering fronts of which the deepest is 76 m beneath the surface. Rock is weathered to varying degrees, contains core stones, and strongly altered zones featuring intensive iron oxidation and high porosity. Geophysical borehole measurements and chemical weathering indicators reveal more intense weathering where fracturing is extensive, and porosity is higher than in bedrock. Only the top 10 m feature a continuous weathering gradient towards the surface. We suggest that tectonic preconditioning by fracturing provided transport pathways for oxygen to greater depths, inducing porosity by oxidation. Porosity was preserved throughout the weathering process, as secondary minerals were barely formed due to the low fluid flow.
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http://dx.doi.org/10.1038/s41598-021-90267-7 | DOI Listing |
Sci Total Environ
October 2024
GFZ German Research Centre for Geosciences, Section Geomicrobiology, 14473 Potsdam, Germany; Institute of Geosciences, University of Potsdam, 14476 Potsdam, Germany. Electronic address:
Front Microbiol
January 2024
GFZ German Research Centre for Geosciences, Section Geomicrobiology, Potsdam, Germany.
The microbiota is attributed to be important for initial soil formation under extreme climate conditions, but experimental evidence for its relevance is scarce. To fill this gap, we investigated the impact of microbial communities and their interrelationship with biocrust and plants compared to abiotic controls on soil formation in initial arid and semiarid soils. Additionally, we assessed the response of bacterial communities to climate change.
View Article and Find Full Text PDFGlob Chang Biol
January 2024
Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich, Jülich, Germany.
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).
View Article and Find Full Text PDFEur J Protistol
October 2023
University of Cologne, Institute of Zoology, General Ecology, 50674 Cologne, Germany. Electronic address:
Cercozoans and heterolobose amoebae are found across terrestrial habitats where they feed on other unicellular microbes, including bacteria, fungi and microalgae. They constitute a significant fraction of soil ecosystems and are integral members of plant microbiota. Here, we present the results on the isolation of protozoans from the rhizosphere and phyllosphere of Browningia candelaris (Meyen) in the Andean Altiplano and Eulychnia taltalensis (F.
View Article and Find Full Text PDFZootaxa
April 2023
Universidade Federal de São Carlos; Campus Sorocaba; CCHB; Departamento de Biologia; Laboratório de Sistemática de Diptera; Rodovia João Leme dos Santos; km 110; Bairro Itinga; Sorocaba-SP; Brazil.
Toxotarsinae is a subfamily of Calliphoridae (Diptera: Calyptratae: Oestroidea) with 11 species currently distributed in three genera: Neta Shannon, 1926, Sarconesia Bigot, 1857, and Toxotarsus Macquart, 1851. All known species are endemic to South America, mostly restricted to areas with cooler temperatures-like high elevation areas of the Andean Cordillera-and lowlands and coastal regions in the subtropical and temperate parts of the continent. The classification of the subfamily has been somewhat controversial, with eleven, mostly monotypic nominal genera established to accommodate its species, mostly due to distinct interpretations of certain controversial characters by different authors.
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