ORCID Profile
0000-0002-7227-0646
Current Organisation
University of Zurich
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Publisher: Cambridge University Press (CUP)
Date: 17-07-2017
DOI: 10.1017/RDC.2017.44
Abstract: Compound-specific radiocarbon analysis (CSRA) of benzene polycarboxylic acids (BPCAs) yields molecular-level, source-specific information necessary to constrain isotopic signatures of pyrogenic carbon. However, the purification of in idual BPCAs requires a multistep procedure that typically results in only microgram quantities of the target analyte(s). Such small s les are highly susceptible to contamination by extraneous carbon, which needs to be minimized and carefully accounted for in order to yield accurate results. Here, we undertook comprehensive characterization and quantification of contamination associated with molecular radiocarbon ( 14 C) BPCA analyses through systematic processing of multiple authentic standards with both fossil and modern 14 C signatures at various concentrations. Using this approach, we precisely apportion the contribution of extraneous carbon with respect to the four implemented subprocedures. Assuming a constant source and quantity of extraneous carbon we correct and statistically evaluate uncertainties in resulting 14 C data. Subsequently, we examine the results of triplicate analyses of reference materials representing four different environmental matrices (sediment, soil, aerosol, riverine natural organic matter) and apportion their BPCA sources in terms of carbon residues derived from biomass or fossil fuel combustion. This comprehensive approach to CSRA facilitates retrieval of robust 14 C data, with application in environmental studies of the continuum of pyrogenic carbon.
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.CHROMA.2013.06.012
Abstract: The analysis of pyrogenic carbon (PyC) in environmental s les is of great interest, e.g. for carbon cycle assessment, (bio-)char characterization and palaeo-environmental or archeological reconstruction. Here, an HPLC method (HPLC) is presented that reproducibly quantifies benzene polycarboxylic acids (BPCA) as molecular markers for PyC in various kinds of environmental s les. It operates at low pH without requiring an organic modifier and was thoroughly tested with PyC reference materials and a peatland core that served as a feasibility and plausibility check. Compared to the established gas chromatography (GC) method, the HPLC method results in higher BPCA quantification reproducibility by showing a significantly smaller coefficient of variation (HPLC: 5%, GC: 16-23%). It works well with small s le amounts, as for instance from sediment cores and aerosol collectors, and requires less s le preparation work than the GC method. Moreover, the here presented HPLC method facilitates (13)C and (14)C analyses on PyC from environmental s les.
Publisher: American Chemical Society (ACS)
Date: 24-10-2017
Abstract: Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 24-05-2023
DOI: 10.1038/S41586-023-06042-3
Abstract: Soils store more carbon than other terrestrial ecosystems 1,2 . How soil organic carbon (SOC) forms and persists remains uncertain 1,3 , which makes it challenging to understand how it will respond to climatic change 3,4 . It has been suggested that soil microorganisms play an important role in SOC formation, preservation and loss 5–7 . Although microorganisms affect the accumulation and loss of soil organic matter through many pathways 4,6,8–11 , microbial carbon use efficiency (CUE) is an integrative metric that can capture the balance of these processes 12,13 . Although CUE has the potential to act as a predictor of variation in SOC storage, the role of CUE in SOC persistence remains unresolved 7,14,15 . Here we examine the relationship between CUE and the preservation of SOC, and interactions with climate, vegetation and edaphic properties, using a combination of global-scale datasets, a microbial-process explicit model, data assimilation, deep learning and meta-analysis. We find that CUE is at least four times as important as other evaluated factors, such as carbon input, decomposition or vertical transport, in determining SOC storage and its spatial variation across the globe. In addition, CUE shows a positive correlation with SOC content. Our findings point to microbial CUE as a major determinant of global SOC storage. Understanding the microbial processes underlying CUE and their environmental dependence may help the prediction of SOC feedback to a changing climate.
Publisher: Elsevier BV
Date: 10-2016
Publisher: MyJove Corporation
Date: 16-05-2016
DOI: 10.3791/53922
Publisher: Elsevier BV
Date: 11-2011
No related grants have been discovered for Michael W. I. Schmidt.