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Quantification of environmental effects on the weathering state of rock surfaces

Gesuchsteller/in Müller Beat
Nummer 137715
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Eawag
Hochschule Eidg. Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz - EAWAG
Hauptdisziplin Hydrologie, Limnologie, Glaziologie
Beginn/Ende 01.11.2011 - 31.03.2015
Bewilligter Betrag 171'689.00
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Alle Disziplinen (2)

Disziplin
Hydrologie, Limnologie, Glaziologie
Geochemie

Keywords (4)

Rock weathering; capillary electrophoresis; biofilm; weathering index

Lay Summary (Englisch)

Lead
Lay summary

The availability of elements that serve as nutrients for a subaerial biofilm and initial soil formation depends critically on the weathering state of rock surfaces. This project aims at the development of a weathering index using a new protocol for sampling and analysis of directly releasable cations from granite. The effects of metabolic activities by microorganisms, temperature, radiation, and precipitation will be validated with experiments in the lab and tested in several field campaigns.

Studies on rock weathering are often focused either on the degradation and dissolution of primary minerals or on catchment studies, where weathering rates are calculated from concentrations of dissolved mineral constituents in the runoff. In contrast, the method we propose to develop aims at the quantification of readily available elements, which emerge from biotic or abiotic weathering processes. The determination of such a weathering index provides a direct measure for the rock surfaces’ reactivities. It allows the investigation of the effects of different environmental factors. Most of the weathering indices defined in the literature are based on the elemental composition of the weathered surface layers in comparison to the parent rock. In contrast, we propose an operational weathering index that reflects the chemical availability of mineral-derived elements. The proposed weathering index is empirically based on the quantitative measurement of mineral-derived elements in a drop of aqueous solution that has been spread onto the investigated rock surface (“drop-on-stone”). Such a protocol requires analytical equipment that is suitable for analyzing very small sample volumes, and that is portable and applicable under field conditions. For this we intend to adapt capillary electrophoreses with capacitatively coupled contactless conductivity detection.

The new method will provide a fast, easy to use and inexpensive tool to quantify the mobilization of ions from rock surfaces due to environmental forcing factors and can be used for related scientific and applied investigations. The weathering index permits the interpretation of the results in a relative scale of the weathering state.

Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Name Institut

Publikationen

Publikation
A novel method to quantify bioavailable elements and mobile ATP on rock surfaces and lichens
Natascha N. Torres, Thomas Chwalek, Helen Droz-Georget, Beat Müller, Helmut Brandl, Peter C. Hauser, Gerhard Furrer (2016), A novel method to quantify bioavailable elements and mobile ATP on rock surfaces and lichens, in Geosciences, 2(3), 245-258.
Early diagenetic processes generate iron and manganese oxide layers in the sediments of Lake Baikal, Siberia
Torres Natascha T., Och Lawrence M., Hauser Peter C., Furrer Gerhard, Brandl Helmut, Vologina Elena, Sturm Michael, Bürgmann Helmut, Müller Beat (2014), Early diagenetic processes generate iron and manganese oxide layers in the sediments of Lake Baikal, Siberia, in Environmental Science - Processes & Impacts, 16, 879-889.
Sediment porewater extraction and analysis combining filter tube samplers and capillary electrophoresis
Torres Natascha T., Hauser Peter C., Furrer Gerhard, Brandl Helmut, Mueller Beat (2013), Sediment porewater extraction and analysis combining filter tube samplers and capillary electrophoresis, in ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS, 15(4), 715-720.

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Goldschmidt Conference Vortrag im Rahmen einer Tagung On-site pore water measurements of Lake Baikal sediments 26.08.2013 Florence, Italien Torres Natascha; Müller Beat; Hauser Peter C.;
Goldschmidt Conference Poster The Influence of Frost Weathering on the Release of Readily Available Ions from Granite Surfaces 26.08.2013 Florence, Italien Furrer Gerhard; Brandl Helmut; Hauser Peter C.; Torres Natascha; Müller Beat;
YES (young environmental scientist meeting) Vortrag im Rahmen einer Tagung Simplify your sediment pore water analysis 11.02.2013 Krakow, Polen Müller Beat; Torres Natascha; Hauser Peter C.;
Eurosoil, 2-6 July 2012, Bari, Italy Poster Drop on stone- a new tool for the quantification of bioavailable elements from weathered rock surfaces 02.07.2012 Bari, Italien Müller Beat; Torres Natascha; Furrer Gerhard;


Verbundene Projekte

Nummer Titel Start Förderungsinstrument
149068 Separation and Detection Methods in the Analytical Sciences 01.10.2013 Projektförderung (Abt. I-III)
140857 Effect of cyanide-mineral interactions on granite weathering in a glacier forefield 01.05.2012 Interdisziplinäre Projekte

Abstract

The availability of elements that serve as nutrients for a subaerial biofilm and initial soil formation depends critically on the weathering state of rock surfaces. This project aims at the development of a weathering index using a new protocol for sampling and analysis of directly releasable cations from granite. The effects of metabolic activities by microorganisms, temperature, radiation, and precipitation will be validated with experiments in the lab and tested in several field campaigns. Studies on rock weathering are often focused either on the degradation and dissolution of primary minerals or on catchment studies, where weathering rates are calculated from concentrations of dissolved mineral constituents in the runoff. In contrast, the method we propose to develop aims at the quantification of readily available elements, which emerge from biotic or abiotic weathering processes. The determination of such a weathering index provides a direct measure for the rock surfaces’ reactivities. It allows the investigation of the effects of different environmental factors. Most of the weathering indices defined in the literature are based on the elemental composition of the weathered surface layers in comparison to the parent rock. In contrast, we propose an operational weathering index that reflects the chemical availability of mineral-derived elements. The proposed weathering index is empirically based on the quantitative measurement of mineral-derived elements in a drop of aqueous solution that has been spread onto the investigated rock surface (“drop-on-stone”). Such a protocol requires analytical equipment that is suitable for analyzing very small sample volumes, and that is portable and applicable under field conditions. For this we intend to adapt capillary electrophoreses (CE) with capacitatively coupled contactless conductivity detection (C4D).The proposed project includes the following objectives: (i) Definition of a standard sampling protocol and adaptation of a CE device for field measurements. (ii) Calibration of the effects of environmental weathering factors (biofilms, temperature, radiation) and their temporal impact on the readily available elements from the surface of granite reference samples. Thereby, the relative contribution of biofilms will be parameterized by ATP measurements. (iii) Tracing of effects from extrinsic factors with freshly broken pieces of granite exposed in an alpine area along environmental gradients. (iv) Application of the method to characterize initial stages of soil formation on rocks along the chronosequence of the Damma Glacier forefield, and (v) establishment of a weathering index using empirical correlations and/or ratios of selected cations and amount of biomass. We apply for the funding of a 3-year PhD position. The new method will provide a fast, easy to use and inexpensive tool to quantify the mobilization of ions from rock surfaces due to environmental forcing factors and can be used for related scientific and applied investigations. The weathering index permits the interpretation of the results in a relative scale of the weathering state.
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