Bernhard Steffen's research while affiliated with Forschungszentrum Jülich and other places

Publications (5)

Article
Recent findings on soil organic matter (SOM) revealed that soil microorganisms are not only crucial for SOM formation through plant litter degradation but soil microbial biomass (SMB) may also directly contribute to SOM and its composition. However, the role and interactions of litter quality, microbial turnover and composition of SMB and SOM remai...
Article
Full-text available
Dissolved organic matter (DOM) is part of the biogeochemical cycles of carbon and nutrients, carries pollutants and drives soil formation. The DOM concentration and properties along the water flow path through forest ecosystems depend on its sampling location and transformation processes. To improve our understanding of the effects of forest manage...
Article
Full-text available
Dissolved organic matter (DOM) is part of the biogeochemical cycles of carbon and nutrients, carries pollutants and drives soil formation. The DOM concentration and properties along the water flow path through forest ecosystems depend on its origin and transformation processes. To improve our understanding of the effects of forest management, espec...
Article
Hair-ice is a rather unknown phenomenon. In contrast to generally known frost needles, originating from atmospheric water and expanding e.g. from plant surfaces in all directions, hair ice grows from the basis of wet, rotten hardwood. The hair-like, flexible, linear structures may reach up to 10 cm in length without any ramifications. Hair-ice appe...

Citations

... Products of microbial metabolism are exuded and excreted by active microbes or released after cell death (Hofman and Dušek 2003), and range from low-molecular weight and soluble compounds (such as simple sugars, organic acids, and amino acids), to proteins and storage and structural polysaccharides (such as starch and chitin). In theory, these structures are not particularly "recalcitrant," that is, not complex in their chemical structure (see Section 2.1) (Hopkins and Dungait 2010;Lorenz et al. 2021;Malik et al. 2016). In vitro decomposition experiments under controlled conditions have shown that they may decompose very rapidly (sometimes in less than an hour), probably because they are rich in energy or nutrients, easily accessible to organisms, and rapidly assimilated (Boddy et al. 2007;Hill et al. 2008). ...
... The concentration, composition, and properties of soil DOM in areas of vegetation restoration depend on the sources and transformation processes. DOM has been shown to be mainly released from the decomposition of deciduous leaf litter, deadwood, plant root exudates, microbial primary and secondary metabolites, and degradation products of soil organic matter [28,36]. DOM is described as a continuum with labile, semi-labile, and refractory pools that are decomposed and utilized by microorganisms on time scales from minutes to millennia [28]. ...
... In addition to the classical OM source tracking tools, such as fluorescence spectroscopy and isotope carbon and nitrogen abundance, other advanced analyses have been applied in the past studies, which included size exclusion chromatography with online organic carbon detector (SEC-OCD; Chen et al., 2016a;Quang et al., 2015), and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS; Derrien et al., 2018b;Thieme et al., 2018). In particular, FT-ICR-MS has a strong merit, because it fully resolves the molecular composition of complex DOM mixtures (Stenson et al., 2002) by assigning molecular formulas to thousands of peaks detected in the mass spectrum of the mixtures (Sleighter and Hatcher, 2008). ...