TY - JOUR A1 - Sommer, Michael A1 - Jochheim, H. A1 - Höhn, Axel A1 - Breuer, Jörn A1 - Zagorski, Z. A1 - Busse, J. A1 - Barkusky, Dietmar A1 - Meier, K. A1 - Puppe, D. A1 - Wanner, Manfred A1 - Kaczorek, Danuta T1 - Si cycling in a forest biogeosystem - the importance of transient state biogenic Si pools JF - Biogeosciences N2 - The relevance of biological Si cycling for dissolved silica (DSi) export from terrestrial biogeosystems is still in debate. Even in systems showing a high content of weatherable minerals, like Cambisols on volcanic tuff, biogenic Si (BSi) might contribute > 50% to DSi (Gerard et al., 2008). However, the number of biogeosystem studies is rather limited for generalized conclusions. To cover one end of controlling factors on DSi, i.e., weatherable minerals content, we studied a forested site with absolute quartz dominance (> 95 %). Here we hypothesise minimal effects of chemical weathering of silicates on DSi. During a four year observation period (05/2007-04/2011), we quantified (i) internal and external Si fluxes of a temperate-humid biogeosystem (beech, 120 yr) by BIOME-BGC (version ZALF), (ii) related Si budgets, and (iii) Si pools in soil and beech, chemically as well as by SEM-EDX. For the first time two compartments of biogenic Si in soils were analysed, i.e., phytogenic and zoogenic Si pool (testate amoebae). We quantified an average Si plant uptake of 35 kg Si ha(-1) yr(-1) - most of which is recycled to the soil by litterfall - and calculated an annual biosilicification from idiosomic testate amoebae of 17 kg Si ha(-1). The comparatively high DSi concentrations (6 mg L-1) and DSi exports (12 kg Si ha(-1) yr(-1)) could not be explained by chemical weathering of feldspars or quartz dissolution. Instead, dissolution of a relictic, phytogenic Si pool seems to be the main process for the DSi observed. We identified canopy closure accompanied by a disappearance of grasses as well as the selective extraction of pine trees 30 yr ago as the most probable control for the phenomena observed. From our results we concluded the biogeosystem to be in a transient state in terms of Si cycling. Y1 - 2013 U6 - https://doi.org/10.5194/bg-10-4991-2013 SN - 1726-4170 VL - 10 IS - 7 SP - 4991 EP - 5007 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Sommer, Michael A1 - Augustin, Jürgen A1 - Kleber, M. T1 - Feedbacks of soil erosion on SOC patterns and carbon dynamics in agricultural landscapes-The CarboZALF experiment T2 - Journal of real-time image processing Y1 - 2016 U6 - https://doi.org/10.1016/j.still.2015.09.015 SN - 0167-1987 SN - 1879-3444 VL - 156 SP - 182 EP - 184 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Sommer, Michael T1 - Nicht-invasive Methoden in der Bodenlandschaftsforschung BT - Konzeption und Projekte N2 - Der Referent ist Leiter des Institutes für Bodenlandschaftsforschung am Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e. V. in Müncheberg. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7117 N1 - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 ER - TY - JOUR A1 - Sommer, C. A1 - Garbusow, Maria A1 - Juenger, E. A1 - Pooseh, S. A1 - Bernhardt, Nadine A1 - Birkenstock, J. A1 - Schad, Daniel A1 - Jabs, B. A1 - Gloeckler, T. A1 - Huys, Quentin J. M. A1 - Heinz, A. A1 - Smolka, Michael N. A1 - Zimmermann, Ulrich S. T1 - Strong seduction: impulsivity and the impact of contextual cues on instrumental behavior in alcohol dependence JF - Translational Psychiatry N2 - Alcohol-related cues acquire incentive salience through Pavlovian conditioning and then can markedly affect instrumental behavior of alcohol-dependent patients to promote relapse. However, it is unclear whether similar effects occur with alcohol-unrelated cues. We tested 116 early-abstinent alcohol-dependent patients and 91 healthy controls who completed a delay discounting task to assess choice impulsivity, and a Pavlovian-to-instrumental transfer (PIT) paradigm employing both alcohol-unrelated and alcohol-related stimuli. To modify instrumental choice behavior, we tiled the background of the computer screen either with conditioned stimuli (CS) previously generated by pairing abstract pictures with pictures indicating monetary gains or losses, or with pictures displaying alcohol or water beverages. CS paired to money gains and losses affected instrumental choices differently. This PIT effect was significantly more pronounced in patients compared to controls, and the group difference was mainly driven by highly impulsive patients. The PIT effect was particularly strong in trials in which the instrumental stimulus required inhibition of instrumental response behavior and the background CS was associated to monetary gains. Under that condition, patients performed inappropriate approach behavior, contrary to their previously formed behavioral intention. Surprisingly, the effect of alcohol and water pictures as background stimuli resembled that of aversive and appetitive CS, respectively. These findings suggest that positively valenced background CS can provoke dysfunctional instrumental approach behavior in impulsive alcohol-dependent patients. Consequently, in real life they might be easily seduced by environmental cues to engage in actions thwarting their long-term goals. Such behaviors may include, but are not limited to, approaching alcohol. Y1 - 2017 U6 - https://doi.org/10.1038/tp.2017.158 SN - 2158-3188 VL - 7 SP - 1209 EP - 1222 PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Singhal, Puja A1 - Pahle, Michael A1 - Kalkuhl, Matthias A1 - Sommer, Stephan A1 - Levesque, Antoine A1 - Berneiser, Jessica T1 - Beyond good faith BT - why evidence-based policy is necessary to decarbonize buildings cost-effectively JF - SSRN eLibrary / Social Science Research Network N2 - The ambitious climate targets set by industrialized nations worldwide cannot be met without decarbonizing the building stock. Using Germany as a case study, this paper takes stock of the extensive set of energy efficiency policies that are already in place and clarifies that they have been designed “in good faith” but lack in overall effectiveness as well as cost-efficiency in achieving these climate targets. We map out the market failures and behavioural considerations that are potential reasons for why realized energy savings fall below expectations and why the household adoption of energy-efficient and low-carbon technologies has remained low. We highlight the pressing need for data and modern empirical research to develop targeted and cost-effective policies seeking to correct these market failures. To this end, we identify some key research questions and identify gaps in the data required for evidence-based policy. KW - energy efficiency KW - decarbonization KW - housing sector KW - heat demand KW - evidence-based policy Y1 - 2021 U6 - https://doi.org/10.2139/ssrn.3947800 SN - 1556-5068 PB - SSRN - Elsevier CY - Rochester, NY ER - TY - JOUR A1 - Siegmund, Nicole A1 - Panebianco, Juan E. A1 - Avecilla, Fernando A1 - Iturri, Laura Antonela A1 - Sommer, Michael A1 - Buschiazzo, Daniel A1 - Funk, Roger T1 - From gustiness to dustiness BT - the impact of wind gusts on particulate matter emissions in field experiments in La Pampa, Argentina JF - Atmosphere N2 - This study delivers the first empirical data-driven analysis of the impact of turbulence induced gustiness on the fine dust emissions from a measuring field. For quantification of the gust impact, a new measure, the Gust uptake Efficiency (GuE) is introduced. GuE provides a percentage of over- or under-proportional dust uptake due to gust activity during a wind event. For the three analyzed wind events, GuE values of up to 150% could be found, yet they significantly differed per particle size class with a tendency for lower values for smaller particles. In addition, a high-resolution correlation analysis among 31 particle size classes and wind speed was conducted; it revealed strong negative correlation coefficients for very small particles and positive correlations for bigger particles, where 5 mu m appears to be an empirical threshold dividing both directions. We conclude with a number of suggestions for further investigations: an optimized field experiment setup, a new particle size ratio (PM1/PM0.5 in addition to PM10/PM2.5), as well as a comprehensive data-driven search for an optimal wind gust definition in terms of soil erosivity. KW - wind gusts KW - wind erosion KW - particle uptake KW - dust plumes Y1 - 2022 U6 - https://doi.org/10.3390/atmos13081173 SN - 2073-4433 VL - 13 IS - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Siegmund, Nicole A1 - Funk, Roger A1 - Sommer, Michael A1 - Avecilla, Fernando A1 - Esteban Panebianco, Juan A1 - Iturri, Laura Antonela A1 - Buschiazzo, Daniel T1 - Horizontal and vertical fluxes of particulate matter during wind erosion on arable land in the province La Pampa, Argentina JF - International journal of sediment research N2 - A detailed analysis of horizontal and vertical particulate matter (PM) fluxes during wind erosion has been done, based on measurements of PM smaller than 10, 2.5, and 1.0 mu mm, at windward and leeward positions on a measuring field. The three fractions of PM measurement are differently influenced by the increasing wind and shear velocities of the wind. The measured concentrations of the coarser fractions of the fine dust, PM10, and PM2.5, increase with wind and shear velocity, whereas the PM1.0 concentrations show no clear correlation to the shear velocity. The share of PM2.5 on PM10 depends on the measurement height and wind speed and varies between 4 and 12 m/s at the 1 m height ranging from 25% to 7% (average 10%), and at the 4 m height from 39% to 23% (average 30%). Although general relationships between wind speed, PM concentration, and horizontal and vertical fluxes could be found, the contribution of the measuring field was very low, as balances of incoming and outgoing fluxes show. Consequently, the measured PM concentrations are determined from a variety of sources, such as traffic on unpaved roads, cattle drives, tillage operations, and wind erosion, and thus, represent all components of land use and landscape structure in the near and far surroundings of the measuring field. The current results may reflect factors from the landscape scale rather than the influence of field-related variables. The measuring devices used to monitor PM concentrations showed differences of up to 20%, which led to considerable deviations when determining total balances. Differences up to 67% between the calculated fluxes prove the necessity of a previous calibration of the devices used. (c) 2022 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. KW - PM10, PM2.5 and PM1.0 concentrations KW - Field measurements KW - Horizontal KW - flux KW - Vertical flux KW - PM balances Y1 - 2022 U6 - https://doi.org/10.1016/j.ijsrc.2022.01.004 SN - 1001-6279 SN - 2589-7284 VL - 37 IS - 5 SP - 539 EP - 552 PB - IRTCES CY - Beijing ER - TY - JOUR A1 - Siegmund, Nicole A1 - Funk, Roger A1 - Koszinsky, Sylvia A1 - Buschiazzo, Daniel A1 - Sommer, Michael T1 - Effects of low-scale landscape structures on aeolian transport processes on arable land JF - Aeolian Research N2 - The landscape of the semiarid Pampa in central Argentina is characterized by late Pleistocene aeolian deposits, covering large plains with sporadic dune structures. Since the current land use changed from extensive livestock production within the Caldenal forest ecosystem to arable land, the wind erosion risk increased distinctly. We measured wind erosion and deposition patterns at the plot scale and investigated the spatial variability of the erosion processes. The wind-induced mass-transport was measured with 18 Modified Wilson and Cooke samplers (MWAC), installed on a 1.44 ha large field in a 20 x 40 m grid. Physical and chemical soil properties from the upper soil as well as a digital elevation model were recorded in a 20 x 20 m grid. In a 5-month measuring campaign data from seven storms with three different wind directions was obtained. Results show very heterogeneous patterns of erosion and deposition for each storm and indicate favoured erosion on windward and deposits on leeward terrain positions. Furthermore, a multiple regression model was build, explaining up to 70% of the spatial variance of erosion by just using four predictors: topsoil thickness, relative elevation, soil organic carbon content and slope direction. Our findings suggest a structure-process-structure complex where the landscape structure determines the effects of recent wind erosion processes which again slowly influence the structure, leading to a gradual increase of soil heterogeneity. KW - Argentina KW - La Pampa KW - Wind erosion KW - Deposition KW - Topography KW - Mass transport KW - MWAC KW - Multiple regression Y1 - 2018 U6 - https://doi.org/10.1016/j.aeolia.2018.03.003 SN - 1875-9637 SN - 2212-1684 VL - 32 SP - 181 EP - 191 PB - Elsevier CY - Oxford ER - TY - GEN A1 - Sebold, Miriam Hannah A1 - Nebe, Stephan A1 - Garbusow, Maria A1 - Schad, Daniel A1 - Sommer, Christian A1 - Rapp, Michael Armin A1 - Smolka, Michael N. A1 - Huys, Quentin J. M. A1 - Schlagenhauf, Florian A1 - Heinz, Andreas T1 - Neurobiological correlates of learning and decision-making in alcohol dependence T2 - European psychiatry : the journal of the Association of European Psychiatrists Y1 - 2017 U6 - https://doi.org/10.1016/j.eurpsy.2017.01.084 SN - 0924-9338 SN - 1778-3585 VL - 41 SP - S11 EP - S11 PB - Elsevier CY - Paris ER - TY - JOUR A1 - Sebold, Miriam Hannah A1 - Nebe, Stephan A1 - Garbusow, Maria A1 - Guggenmos, Matthias A1 - Schad, Daniel A1 - Beck, Anne A1 - Kuitunen-Paul, Sören A1 - Sommer, Christian A1 - Frank, Robin A1 - Neu, Peter A1 - Zimmermann, Ulrich S. A1 - Rapp, Michael Armin A1 - Smolka, Michael N. A1 - Huys, Quentin J. M. A1 - Schlagenhauf, Florian A1 - Heinz, Andreas T1 - When Habits Are Dangerous: Alcohol Expectancies and Habitual Decision Making Predict Relapse in Alcohol Dependence JF - Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry N2 - BACKGROUND: Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS: Ninety detoxified, medication-free, alcohol-dependent patients and 96 age-and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS: Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS: These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies. KW - Alcohol dependence KW - Alcohol expectancy KW - Goal-directed control KW - Medial prefrontal cortex KW - Reinforcement learning KW - Treatment outcome Y1 - 2017 U6 - https://doi.org/10.1016/j.biopsych.2017.04.019 SN - 0006-3223 SN - 1873-2402 VL - 82 SP - 847 EP - 856 PB - Elsevier CY - New York ER -