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Institucional

Oeser, Ralf A.

Stroncik, Nicole#Moskwa, Lisa-Marie#Bernhard, Nadine#Schaller, Mirjam#Canessa, Rafaella#van den Brink, Liesbeth#Koester, Moritz#Brucker, Emanuel#Stock, Svenja#Pablo Fuentes, Juan#Godoy, Roberto#Javier Matus, Francisco#Oses Pedraza, Romulo#Osses McIntyre, Pablo#Paulino, Leandro#Seguel, Oscar#Bader, Maaike Y.#Boy, Jens#Dippold, Michaela A.#Ehlers, Todd A.#Kuehn, Peter#Kuzyakov, Yakov#Leinweber, Peter#Scholten, Thomas#Spielvogel, Sandra#Spohn, Marie#Ubernickel, Kirstin#Tielboerger, Katja#Wagner, Dirk#von Blanckenburg, Friedhelm

Chemistry and microbiology of the Critical Zone along a steep climate and vegetation gradient in the Chilean Coastal Cordillera

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"The Chilean Coastal Cordillera features a spectacular climate and vegetation gradient, ranging from arid and unvegetated areas in the north to humid and forested areas in the south. The EarthShape project (""Earth Surface Shaping by Biota"") uses this natural gradient to investigate how climate and biological processes shape the Earth's surface. We explored the Critical Zone, the Earth's uppermost layer, in four key sites located in desert, semidesert, Mediterranean, and temperate climate zones of the Coastal Cordillera, with the focus on weathering of granitic rock. Here, we present first results from 16 approximately 2 m-deep regolith profiles to document: (1) architecture of weathering zone, (2) degree and rate of rock weathering, thus the release of mineral-derived nutrients to the terrestrial ecosystems, (3) denudation rates, and (4) microbial abundances of bacteria and archaea in the saprolite. From north to south, denudation rates from cosmogenic nuclides are similar to 10 t km(-2) yr(-1) at the arid Pan de Aziicar site, similar to 20 t km(2) yr(-1) at the semi-arid site of Santa Gracia, -60 t km(-2) yr(-1) at the Mediterranean climate site of La Campana, and similar to 30 t km(-2) yr(-1) at the humid site of Nahuelbuta. A and B horizons increase in thickness and elemental depletion or enrichment increases from north (similar to 26 degrees S) to south (similar to 38 degrees S) in these horizons. Differences in the degree of chemical weathering, quantified by the chemical depletion fraction (CDF), are significant only between the arid and sparsely vegetated site and the other three sites. Differences in the CDF between the sites, and elemental depletion within the sites are sometimes smaller than the variations induced by the bedrock heterogeneity. Microbial abundances (bacteria and archaea) in saprolite substantially increase from the arid to the semi-arid sites. With this study, we provide a comprehensive dataset characterizing the Critical Zone geochemistry in the Chilean Coastal Cordillera. This dataset confirms climatic controls on weathering and denudation rates and provides prerequisites to quantify the role of biota in future studies."

Artículo original

Special thanks to CONAF for giving us the opportunity to work in the national parks of Pan de Azucar, La Campana, and Nahuelbuta. We also thank CEAZA for facilitating access to the Reserva Natural Santa Gracia. We thank Anja Schleicher at GFZ Section 3.1 Inorganic and Isotope Geochemistry for support of XRF analyses. We are grateful for the comments of two anonymous reviewers that helped to improve this paper. This project is funded by the German Science Foundation DFG-SPP 1803 (EarthShape, www.earthshape.net).

10.1016/j.catena.2018.06.002

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Weathering# Denudation# Microbial abundance# Climate# Chile

Weathering# Denudation# Microbial abundance# Climate# Chile

http://dx.doi.org/10.1016/j.catena.2018.06.002

Geosciences, Multidisciplinary# Soil Science# Water Resources

Desgaste# Denudación# Abundancia microbiana# Clima# Chile

Desgaste# Denudación# Abundancia microbiana# Clima# Chile

WOS:000441681500017

Chemistry and microbiology of the Critical Zone along a steep climate and vegetation gradient in the Chilean Coastal Cordillera

Artículo original

version publicada

ELSEVIER

CATENA

Geociencias, Multidisciplinaria# ciencia del suelo# Recursos hídricos

0341-8162

en

DFG SPP 1803

Special thanks to CONAF for giving us the opportunity to work in the national parks of Pan de Azucar, La Campana, and Nahuelbuta. We also thank CEAZA for facilitating access to the Reserva Natural Santa Gracia. We thank Anja Schleicher at GFZ Section 3.1 Inorganic and Isotope Geochemistry for support of XRF analyses. We are grateful for the comments of two anonymous reviewers that helped to improve this paper. This project is funded by the German Science Foundation DFG-SPP 1803 (EarthShape, www.earthshape.net).

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