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Amino acid turnover in soil is an important element of terrestrial carbon and nitrogen cycles. This study accounts for their driver - the microbial metabolism - by tracing them via the unique isotopic approach of position-specific labeling. Three 14C isotopomers of alanine at five concentration levels combined with selective sterilization were used to(More)
A positive plant diversity to plant aboveground productivity relation has been shown to alter carbon and nitrogen fluxes in soils. Thus, most investigations focussed on the C- and N-input via litter fall, widely neglecting the importance of root exudation. As microbes, which are known to be important drivers of matter fluxes in soil, feed on these root(More)
The application of biochar (BC) in conjunction with mineral fertilizers is one of the most promising management practices recommended to improve soil quality. However, the interactive mechanisms of BC and mineral fertilizer addition affecting microbial communities and functions associated with soil organic matter (SOM) cycling are poorly understood. We(More)
Faeces incorporation can alter the concentration patterns of stanols, stanones, Δ(5)-sterols and bile acids in soils and terrestrial sediments. A joint quantification of these substances would give robust and specific information about the faecal input. Therefore, a method was developed for their purification and determination via gas chromatography-mass(More)
Natural forests in Ethiopia are frequently replaced by Cupressus lusitanica plantations, but little is known about consequences of this land use change for soil C and N dynamics. The objectives of the study were: (i) quantification of microbial incorporation of litter-derived C and N under field conditions, (ii) identification of forest management effects(More)
Biopores are hotspots of nutrient mobilisation and shortcuts for carbon (C) into subsoils. C processing relies on microbial community composition, which remains unexplored in subsoil biopores. Phospholipid fatty acids (PLFAs; markers for living microbial groups) and amino sugars (microbial necromass markers) were extracted from two subsoil depths (45–75 cm(More)
RATIONALE Amino sugars build up microbial cell walls and are important components of soil organic matter. To evaluate their sources and turnover, δ(13)C analysis of soil-derived amino sugars by liquid chromatography was recently suggested. However, amino sugar δ(13)C determination remains challenging due to (1) a strong matrix effect, (2) CO2 -binding by(More)
CO2 release from soil is commonly used to estimate toxicity of various substances on microorganisms. However, the mechanisms underlying persistent CO2 release from soil exposed to toxicants inhibiting microbial respiration, for example, sodium azide (NaN3) or heavy metals (Cd, Hg, Cu), remain unclear. To unravel these mechanisms, NaN3-amended soil was(More)
Although biogeochemical models designed to simulate carbon (C) and nitrogen (N) dynamics in high-latitude ecosystems incorporate extracellular parameters, molecular and biochemical adaptations of microorganisms to freezing remain unclear. This knowledge gap hampers estimations of the C balance and ecosystem feedback in high-latitude regions. To analyze(More)