Das Projekt "Does traditional Alpine farming alter greenhouse gas emissions and C-turnover in remote mountain streams? (Marie Heim-Voegtlin Beiträge)" wird vom Umweltbundesamt gefördert und von Ecole Polytechnique Federale de Lausanne (EPFL), Faculte de l'Evironnement Naturel, Architectural et Construit (ENAC), IIE, Stream Biofilm and Ecosystem Research Laboratory (SBER) durchgeführt. Because inland waters only cover a small portion (6-15%) of the terrestrial surface they are often not regarded as an important component of the global carbon (C) cycle. However, as part of the terrestrial landscape these active, rather than passive, conduits receive and transform substantial amounts of organic C. In fact, the global carbon dioxide (CO2) emissions from inland waters was estimated to be about 1.4 Gt C year-1 corresponding to about 50 % of the terrestrial C sink. Together with methane (CH4) this results in C emissions from inland waters that correspond to about 75 % of the terrestrial sink. However, there is a large degree of uncertainty in these estimates as most studies on rivers and streams have focused on CO2 emissions, with little research performed on CH4 emissions and turnover processes. Furthermore, studies on C-fluxes and turnover processes in small streams are highly under-represented. Thus, the overall objective of this proposal is to study the dynamics of C fluxes (CO2 and CH4), and the pathways of CH4 production in Alpine streams influenced by managed Alpine pastures, thereby adding another puzzle piece to the understanding of C-cycling in small streams It is still common in Switzerland to drive livestock up into the Alps for summer farming and grazing. However, the associated fecal and urine deposits may strongly influence the species composition of the vegetation in mountain meadows, the quality of soil organic matter and thus dissolved organic matter quality entering adjacent streams. Once the organic matter enters the stream in particulate and/or dissolved form, it will be degraded by microbes either aerobically or anaerobically (or both) while producing CO2 and CH4. CH4 can be produced via acetate fermentation or CO2 reduction. Which of these two pathway used for CH4 production depends on the quality and age of the organic matter. The effect of Alpine summer farming on C emissions (CO2 and CH4) and C turnover processes will be investigated in headwaters draining intensely farmed Alpine/subalpine pastures. A field study will be performed based on 1) a stable isotope approach, 2) resolving CH4 and CO2 fluxes, 3) investigating the CH4 production pathways and 4) changes in microbial communities.
Das Projekt "Can community transcription profiles be used to predict environmental biotransformation of organic contaminants?" wird vom Umweltbundesamt gefördert und von Eidgenössische Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz durchgeführt. Rapid introduction of new synthetic chemicals into commerce as well as the tens of thousands of legacy chemicals with no appropriate environmental fate information have created the need for tools that predict the fate of these chemicals in the environment. Biodegradation is a primary mechanism potentially reducing the risk of exposure to these chemicals, but incomplete biodegradation may result in an accumulation of biotransformation products that may have similar detrimental effects as their parent chemicals to both human and ecosystem health. Structure-biodegradation relationships have been developed as tools to predict biotransformation half-lives and pathways, but lack specificity for individual environmental compartments, leading to large uncertainties in the prediction of half-lives and over-prediction of biotransformation products that may be formed. In this proposal, we propose to investigate the possibility to improve the specificity of biotransformation prediction by considering not only chemical structure, but also the metabolic potential of the microbial communities residing in the environment in which the compound may undergo biotransformation. The aim of this work is to test the hypothesis that gene transcription levels in microbial communities can be used to predict the extent of specific biotransformation reactions. We will do this by simultaneous characterization of microbial communities in terms of their biotransformation capacity and their gene transcription profile using metatranscriptome sequencing. We will test the hypothesis at the level of well-established enzyme-compound pairs to investigate the utility of the metatranscriptomic approach in an environmental system setting. The results of this inherently interdisciplinary project are expected to significantly contribute to the fields of environmental chemistry and environmental microbiology. Most directly, the results will facilitate more accurate and community-specific predictions of biotransformation of synthetic organic chemicals. Further, we envision contributions to improving accuracy in environmental fate and persistence modeling, development of bioremediation/bioaugmentation strategies, and shedding light on fundamental questions about microbial community formation and structure and how that relates to community function.