@article{RudolphMohrGottfriedLamshoeftetal.2015,
  author    = {Rudolph-Mohr, Nicole and Gottfried, Sebastian and Lamsh{\"o}ft, Marc and Z{\"u}hlke, Sebastian and Oswald, Sascha and Spiteller, Michael},
  title     = {Non-invasive imaging techniques to study O-2 micro-patterns around pesticide treated lupine roots},
  series = {Geoderma : an international journal of soil science},
  volume    = {239},
  journal   = {Geoderma : an international journal of soil science},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0016-7061},
  doi       = {10.1016/j.geoderma.2014.10.022},
  pages     = {257 -- 264},
  year      = {2015},
  abstract  = {The soil root interface is a highly heterogeneous system, e.g. in terms of O-2 and pH distribution. The destructive character of conventional methods disturbs the natural conditions of those biogeochemical gradients. Therefore, experiments aiming to control these influences and study pesticide kinetics under given O-2 and pH conditions suffer from a large uncertainty of the "real" O-2/pH at a certain position. Our approach with two different imaging techniques will examine the soil-root interface as well as the dissipation of the applied pesticide at a high spatial resolution. The obtained outcomes show directly that the pH has an influence on enantioselective dissipation of the acetanilide fungicide metalaxyl. In areas with high pH from an applied racemic mixture, the R-enantiomer dissipates faster than the S-enantiomer. Moreover, we found significantly reduced oxygen values in the bulk soil and vicinity of metalaxyl treated roots compared to control plant roots. The combination of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) and fluorescence imaging indicated the oxygen-dependent behavior of metalaxyl at the root surface. The results presented here underline the great potential of combining different imaging methods to examine the soil-root interfaces as well as the dissipation of organic pollutants in small soil compartments. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@phdthesis{RudolphMohr2013,
  author    = {Rudolph-Mohr, Nicole},
  title     = {A novel non-invasive optical method for quantitative visualization of pH and oxygen dynamics in soils},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66993},
  school      = {Universit{\"a}t Potsdam},
  year      = {2013},
  abstract  = {In soils and sediments there is a strong coupling between local biogeochemical processes and the distribution of water, electron acceptors, acids and nutrients. Both sides are closely related and affect each other from small scale to larger scales. Soil structures such as aggregates, roots, layers or macropores enhance the patchiness of these distributions. At the same time it is difficult to access the spatial distribution and temporal dynamics of these parameter. Noninvasive imaging techniques with high spatial and temporal resolution overcome these limitations. And new non-invasive techniques are needed to study the dynamic interaction of plant roots with the surrounding soil, but also the complex physical and chemical processes in structured soils. In this study we developed an efficient non-destructive in-situ method to determine biogeochemical parameters relevant to plant roots growing in soil. This is a quantitative fluorescence imaging method suitable for visualizing the spatial and temporal pH changes around roots. We adapted the fluorescence imaging set-up and coupled it with neutron radiography to study simultaneously root growth, oxygen depletion by respiration activity and root water uptake. The combined set up was subsequently applied to a structured soil system to map the patchy structure of oxic and anoxic zones induced by a chemical oxygen consumption reaction for spatially varying water contents. Moreover, results from a similar fluorescence imaging technique for nitrate detection were complemented by a numerical modeling study where we used imaging data, aiming to simulate biodegradation under anaerobic, nitrate reducing conditions.},
  language  = {en}
}
@article{RezaRottlerHerklotzetal.2015,
  author    = {Reza, M. Toufiq and Rottler, Erwin and Herklotz, Laureen and Wirth, Benjamin},
  title     = {Hydrothermal carbonization (HTC) of wheat straw: Influence of feedwater pH prepared by acetic acid and potassium hydroxide},
  series = {Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformation, production technologies},
  volume    = {182},
  journal   = {Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformation, production technologies},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0960-8524},
  doi       = {10.1016/j.biortech.2015.02.024},
  pages     = {336 -- 344},
  year      = {2015},
  abstract  = {In this study, influence of feedwater pH (2-12) was studied for hydrothermal carbonization (HTC) of wheat straw at 200 and 260 degrees C. Acetic acid and KOH were used as acidic and basic medium, respectively. Hydrochars were characterized by elemental and fiber analyses, SEM, surface area, pore volume and size, and ATR-FTIR, while HTC process liquids were analyzed by HPLC and GC. Both hydrochar and HTC process liquid qualities vary with feedwater pH. At acidic pH, cellulose and elemental carbon increase in hydrochar, while hemicellulose and pseudo-lignin decrease. Hydrochars produced at pH 2 feedwater has 2.7 times larger surface area than that produced at pH 12. It also has the largest pore volume (1.1 x 10(-1) ml g(-1)) and pore size (20.2 nm). Organic acids were increasing, while sugars were decreasing in case of basic feedwater, however, phenolic compounds were present only at 260 degrees C and their concentrations were increasing in basic feedwater. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{PestryakovaHerzschuhGorodnichevetal.2018,
  author    = {Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike and Gorodnichev, Ruslan and Wetterich, Sebastian},
  title     = {The sensitivity of diatom taxa from Yakutian lakes (north-eastern Siberia) to electrical conductivity and other environmental variables},
  series = {Polar research : a Norwegian journal of Polar research},
  volume    = {37},
  journal   = {Polar research : a Norwegian journal of Polar research},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0800-0395},
  doi       = {10.1080/17518369.2018.1485625},
  pages     = {16},
  year      = {2018},
  abstract  = {Relative abundances of 157 diatom taxa from Yakutian lake surface-sediments were investigated for their potential to indicate certain environmental conditions. Data from 206 sites from Arctic, sub-Arctic and boreal environments were included. Redundancy analyses were performed to assess the explanatory power of mean July temperature (T-July), conductivity, pH, dissolved silica concentration, phosphate concentration, lake depth and vegetation type on diatom species composition. Boosted regression tree analyses were performed to infer the most relevant environmental variables for abundances of individual taxa and weighted average regression was applied to infer their respective optimum and tolerance. Electrical conductivity was best indicated by diatom taxa. In contrast, only few taxa were indicative of Si and water depth. Few taxa were related to specific pH values. Although T-July, explained the highest proportion of variance in the diatom spectra and was, after conductivity, the second-most selected splitting variable, we a priori decided not to present indicator taxa because of the poorly understood relationship between diatom occurrences and T-July. In total, 92 diatom taxa were reliable indicators of a certain vegetation type or a combination of several types. The high numbers of indicative species for open vegetation sites and for forested sites suggest that the principal turnover is the transition from forest-tundra to northern taiga. Overall, our results reveal that preference ranges of diatom taxa for environmental variables are mostly broad, and the use of indicator taxa for the purposes of environmental reconstruction or environmental monitoring is therefore restricted to marked rather than subtle environmental transitions.},
  language  = {en}
}