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"Igarka" - Linking soil architecture formation with changing permafrost regime to carbon turnover in high latitude soils at multiple spatial scales

Supervisor:

Dr. Leopold Sauheitl

Researcher:

Ina Haase

Duration:

2013-2017

Funded by:

Deutsche Forschungsgemeinschaft: DFG-Projekt (SA2521/1-1)

Brief description:

Most soils develop distinct soil architecture during pedogenesis and soil organic carbon (SOC) is sequestered within a hierarchical system of mineral-organic associations and aggregates. Permafrost soils store large amounts of carbon due to their permanently frozen subsoil and a lack of oxygen in the active layer, but they lack complex soil structure. With permafrost thaw more oxidative conditions and increasing soil temperature presumably enhance the build-up of more complex units of soil architecture and may counterbalance, at least partly, SOC mineralization. We aim to explore the development of mineral-organic associations and aggregates under different permafrost impact with respect to SOC stabilization. This information will be linked to environmental control factors relevant for SOC turnover at the pedon and stand scale to bridge processes occurring at the aggregate scale to larger spatial dimensions. We will combine in situ spectroscopic techniques with fractionation approaches and identify mechanisms relevant for SOC turnover at different scales by multivariate statistics and variogram analyses. From this we expect a deeper knowledge about soil architecture formation in the transition of permafrost soils to terrestrial soils and a scale-spanning mechanistic understanding of SOC cycling in permafrost regions.

 

 

A pore network model of soil water repellency: Model implementation and experimental validation

Supervisor:

Prof. Dr. Andrea Carminati (Georg-August-Universität Göttingen) und Prof. Dr. Jörg Bachmann

Duration:

2017-

Brief description:

Soil water repellency has a big impact on soil quality: it reduces the water holding capacity and it enhances overland flow, soil erosion and preferential leaching of agrochemicals. Better understanding of the mechanisms controlling soil water repellency is therefore needed for the sustainable use of water and soil resources. Existing studies demonstrated that soil hydrophobicity is strongly related to two factors: soil organic matter and soil water content. The experiments indicated a threshold behaviour: above a critical water content soils with a given percentage of soil organic matter are wettable (Contact Angle90). The critical water content decreases with increasing soil organic content. Although there are empirical models that are able to effectively mimic this hydraulic behaviour, a mechanistic model that is able to predict occurrence of soil water repellency for varying soil properties is missing. Objective of this project is to implement and experimentally validate a pore-scale model that is capable to predict the occurrence of water repellency in soils of various texture, water content and soil organic content.

 

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Accumulation, transformation, and stabilization of organic nitrogen along a mineralogical soil gradient

Supervisor:

Dr. Robert Mikutta und Prof. Dr. Axel Schippers (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR)

Researcher:

Sandra Meyer-Stüve

Duration:

2012-

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

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Biogeochemical reactivity of Fe-organic matter coprecipitates

Supervisor:

Dr. Robert Mikutta

Duration:

2010-

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

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Biogeochemistry in temperate forest of southern Chile: C and N fluxes in pristine environments versus sites with change in land use

Supervisor:

Prof. Dr. Roberto Godoy, Dr. Jens Boy

Duration:

2011-2013

Funded by:

FONDECYT (Fondo Nacional de Desarollo Cientifico y Tecnologico)

Brief description:

Chilean old-growth forests are relatively unpolluted compared with forest ecosystems of the Northern Hemisphere, so they can act as blueprints for preindustrial deposition regimes in biogeochemical research. The general objective of this project is to provide the scientific baseline information on the biogeochemical cycles in temperate rainforests and the quantification of nutrient fluxes as inputs from - and emissions to - the atmosphere. Furthermore, investigating into the overall nutrient budgets of pristine and land-used microcatchments aims to understand the long-term sustainability of Chilean forest ecosystems by elucidating whether atmospheric nutrient deposition and nutrient yields of mineral weathering taken together can overcome nutrient losses via outgassing and leaching from the ecosystem.

 

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Biological weathering in a soil chronosequence of the glacier retreat in the Antarctican Fildes Peninsula

Supervisor:

Prof. Dr. Roberto Godoy, Dr. Jens Boy

Duration:

2012-2015

Funded by:

Proyecto INACH T_28-11 Instituto Antarctico Chileno

Brief description:

Mineral weathering is of utmost importance for the support of life on earth, as it turns bedrock into soil and delivers nutrients to organisms. Recently, evidence hardened that biogenic weathering, the weathering induced by biota, might contribute more to weathering rates than the physico-chemical weathering, thus turning weathering into an active process fueled by photosynthesis.

 

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BONARES - CATCHY- Catch-cropping as an Agrarian Tool for Continuing Soil Health and Yield increase

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Jens Boy

Researcher:

Norman Gentsch

Duration:

2015-2018

Funded by:

Bundesministerium für Bildung und Forschung (BMBF)

Brief description:

CATCHY will develop innovative farming systems and soil management strategies for preserving and improving soil fertility towards a more sustainable land use through the integration of catch crops, with possible applications in the upgrade of marginal locations.

 

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BONARES - ORDIAMUR- Overcoming replant disease by an integrated approach

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Jens Boy

Researcher:

Jessica Schimmel

Duration:

2015-2018

Funded by:

Bundesministerium für Bildung und Forschung (BMBF)

Brief description:

Replant disease, also described as soil decline, is known for centuries, however, up to now the ultimate causes are unknown. After repeated growing of the same plant species, the soil loses its capacity to produce plants of the respective species. Poor vegetative development, stunted growth and reduced yield are visible plant reactions. In annual plants, crop rotation and change of cultivation sites are strategies to overcome replant disease. But these strategies are usually not available for woody species being produced in nursery and fruit production centers. The replant diseased soils can not be used for up to 20-30 years, unless soil disinfection is applied. But the disinfectants are ecologically harmful, and the development of alternative approaches is absolutely essential to maintain a sustainable soil productivity. Within the project ORDIAmur this shall be achieved by an integrated approach that aims at understanding and controlling the processes in the rhizosphere that are induced by the plant.

 

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Carbiocial: Carbon sequestration, biodiversity and social structures in Southern Amazonia: models and implementation of carbon-optimized land management strategies - Carbon stocks, turnover and nutrient budgets in soil along land-use and climatic gradients

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Jens Boy und Prof. Dr. Wolfgang Wilcke (Universität Bern)

Researcher:

Simone Strey, Robert Strey

Duration:

2011-2016

Funded by:

Bundesministerium für Bildung und Forschung (BMBF)

Brief description:

Our subproject of the integrated project CARBIOCIAL will provide information about the soil organic carbon (SOC) stocks, as well as the quality and function of SOM, how these parameters are influenced by land use and under changing climate and, finally, identify what innovative management tools can be used to increase C storage in stable SOM pools and to improve SOM and quality of soils along the agricultural frontier in Brazil.

 

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CARBO-Extreme - The terrestrial carbon cycle under climate variability and extremes - a Pan-European synthesis

Supervisor:

Markus Reichstein

Duration:

2009-

Funded by:

EU

 

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Carbonatisierung

Carbonatisierung von porösen Gesteinen durch Wechselwirkung mit magmatischen und hydrothermalen Fluiden – eine Fallstudie am Vulkan Unzen, Japan

Supervisor:

Prof. Dr. Harald Behrens, PD Dr. Stefan Dultz

Researcher:

Anna Simonyan

Duration:

2009-

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

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Diffusion and advection with sorption of anions, cations and non-polar molecules in organo-clays at varying thermo-chemical conditions validation by analytical methods and molecular simulation

Supervisor:

Dr. B. Schampera, PD Dr. S. Dultz

Duration:

2012-2015

Funded by:

D-A-C-H (grenzüberschreitende Förderung), Deutsche Forschungsgemeinschaft (DFG), Fond für wissenschaftliche Förderung (Österreich, FWF)

 

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EARTHSHAPE – BIOSOILS: Biogenic weathering: opening the black box with new isotope systems and in situ mineral decomposition experiments

Supervisor:

Dr. Jens Boy, Prof. Dr. Georg Guggenberger, Prof. Dr. Robert Mikutta

Researcher:

NN

Duration:

2015-2018

Funded by:

Deutsche Forschungsgemeinschaft. DFG Projekt BO 3741/ 4-1

Brief description:

This project links the disciplines of Geology/Geochemistry and Environmental Ecology/Soil Sciences to jointly explore the role of biogenic weathering for linking denudation (removal of mass) and soil production (supply of regolith mass from rock or from dust). We hypothesize that such biogenic weathering is controlled by nutrient demand of the photoautotroph community of an ecosystem to maintain the long-term nutritional status-quo. We shall research into the potential biogenic weathering with in situ mineral decomposition experiments and identify the effective mineral sources from which biota obtain their nutrients using novel isotope ratio systems.

 

 

Impact of bacterial biomass on the surface wettability of soil particles under varying moisture conditions

Supervisor:

Dr. Marc-Oliver Göbel, Prof. Dr. Jörg Bachmann

Researcher:

Dr. Marc-Oliver Göbel

Duration:

2016-2019

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

 

Research Unit 1806-2: "SubSOM - The forgotten part of carbon cycling: Organic matter storage and turnover" - Subproject 5: Origin and fate of dissolved organic matter in the subsoil driven by dynamic exchange and remobilization processes.

Supervisor:

Georg Guggenberger, Karsten Kalbitz (TU Dresden), Robert Mikutta (MLU Halle-Wittenberg)

Researcher:

Patrick Liebmann

Duration:

2017-2020

Funded by:

German Research Foundation (DFG)

Brief description:

Results obtained so far from the subsoil observatories and sequential column experiments indicate a cascade of sorption-desorption processes of dissolved organic matter (DOM) on soil minerals while travelling to the subsoil. Further, results suggest that the sorption capacity of the subsoil is limited, possibly due to high C loading of the reactive minerals in the sandy soil. We assume that the microbial activity might depend on the C loading of the minerals controlling remobilization processes, in addition to the composition of organic matter (OM) on mineral surfaces. Consequently, in the second phase we will address the complex interplay of continuous sorption processes combined with microbial processes and subsequent remobilization depending on source and composition of OM and surface characteristics of the mineral phase. We hypothesize that (i) the composition of DOM entering the mineral soil affects exchange/remobilization processes stronger in the upper part of the soil than deeper subsoil due to an increased microbial processing with increasing soil depth, (ii) the exchange/remobilization of sorbed OM increases with increasing C loading of the minerals, and (iii) microbial transformation of mineral-associated OM is an important source of DOM in larger soil depths. We will approach these hypotheses by a set of experiments starting from complex field conditions to controlled laboratory approaches. The field approaches include a DO13C switch-off pulse in the Grinderwald observatories and a DO13C injection experiment at Grinderwald and two regional sites to study the fate of DOM of different source and composition in the subsoil depending on mineralogical properties and microbial activity. In a comparative way, sorption capacity, C loading, spatial C distribution, C exchange, and OM composition and decomposability (the latter determined by P6) on mineral surfaces will be related to source, composition, C exchange, and microbial stability of DOM. A similar analytical approach will be performed in flow cell experiments, where under defined boundary conditions transport, sorption, and mineralization of the applied DO13C will be assessed. Finally, in a laboratory column experiment with 13C-labeled DOM the effects of microbial activity, manipulated by different incubation temperatures, on the translocation of DOM by sorption and exchange/remobilization processes depending on the mineral surface properties will be studied.

 

 

Research group 1806: "SubSOM - The forgotten part of carbon cycling: Organic matter storage and turnover" - Subproject 4: Micro-scaled Hydraulic Heterogeneity in Subsoils

Supervisor:

Prof. Dr. Jörg Bachmann

Researcher:

Jiem Krüger

Duration:

2013-2017

Brief description:

The main subject of this project is to determine if physical constrains could explain low turnover rates of organic carbon in subsoils. Combining the information from physical structure of the soil (local bulk density, macropore strucuture, aggregation, texture gradients) with surface properties of particles or aggregate surfaces should result in a comprehensive set of physical important parameters and its relevance for an enforcing effect on the hydraulic heterogeneity of the subsoil flow system during wetting and drying. Pore space heterogeneity will be measured via x-ray radiography in flow cells. Interdisciplinary cooperation within the research program is realized by using these flow cell samples to match the special patterns of physical, chemical and biological factors like enzyme activities and spatial distribution of texture, organic carbon and iron oxide content using IR mapping.

 

 

Research group 1806: "SubSOM - The forgotten part of carbon cycling: Organic matter storage and turnover" - Subproject 5: Origin and fate of dissolved organic matter in the subsoil

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Robert Mikutta und Prof. Dr. Karsten Kalbitz (University of Amsterdam)

Researcher:

Timo Leinemann

Duration:

2013-2016

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

Dissolved organic matter (DOM) is one major source of subsoil organic matter (OM). P5 aims at quantifying the impact of DOM input, transport, and transformation to the OC storage in the subsoil environment. The central hypotheses of this proposal are that in matric soil the increasing 14C age of organic carbon (OC) with soil depth is due to a cascade effect, thus, leading to old OC in young subsoil, whereas within preferential flowpaths sorptive stabilization is weak, and young and bioavailable DOM is translocated to the subsoil at high quantities. These hypotheses will be tested by a combination of DOC flux measurements with the comparative analysis of the composition and the turnover of DOM and mineral-associated OM. The work programme utilizes a DOM monitoring at the Grinderwald subsoil observatory, supplemented by defined experiments under field and laboratory conditions, and laboratory DOM leaching experiments on soils of regional variability. A central aspect of the experiments is the link of a 13C-leaf litter labelling experiment to the 14C age of DOM and OM. With that P5 contributes to the grand goal of the research unit and addresses the general hypotheses that subsoil OM largely consists of displaced and old OM from overlying horizons, the sorption capacity of DOM and the pool size of mineral-associated OM are controlled by interaction with minerals, and that preferential flowpaths represent 'hot spots' of high substrate availability.

 

 

Research group 2337 "Denitrification in Agricultural Soils: Integrated Control and Modelling at Various Scales (DASIM)" - Subproject P3: Relevance of functional soil organic matter fractions for kinetics and spatiotemporal patterns of denitrification

Supervisor:

Prof. Dr. Jürgen Böttcher und Prof. Dr. Robert Mikutta (Martin-Luther-Universität Halle-Wittenberg)

Researcher:

NN

Duration:

2016-2019

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

[Translate to Englisch:] Denitrification is a key transformations process, which returns nitrogen (N) from soil back into the atmosphere as N2 and N oxides and therefore plays an important role for the closure of the global N cycle. Despite soil organic matter (OM) is known to fuel denitrification by acting as an electron donor, the role of OM quality and its spatial and temporal bioavailability is only poorly understood. Such information is mandatory for understanding and predicting the "hot-spot"─ and "hotmoment"─ behavior of N trace gas emissions from agricultural soils. This project aims to study the effect of OM type and composition on soil denitrification. Particularly, we will link the properties and abundance of different functional OM fractions (dissolved, particulate, and mineral-associated OM) to the onset and extent of soil denitrification and the respective gas products. Controlled incubation experiments utilizing different organic substrates and soil aggregate size-fractions will be conducted to derive rate equations for denitrification as well as threshold oxygen concentrations and to identify the prime locations of soil denitrification activity. The spatial arrangement of OM in soil will be evaluated microscopically using thin sections of aggregates. Based on OM properties, as judged from element analytics, 13C-NMR and X-ray photoelectron spectroscopy, and denitrification data we will develop an OM-specific quality index for implementation and use in denitrification models.

 

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Research Training Group GRK 1798 „Signaling at the Plant-Soil Interface“- Topic 4: Mechanisms of carbon-nutrient trading in mycorrhizal symbioses and consequences for carbon sequestration in soils

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Jens Boy

Researcher:

Cornelia Schneider, Alberto Andrino de la Fuente, Mauricio Aguirre Morales

Duration:

2013-2016 (max. 2022)

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

This topic is based on the new concept that storage and turnover of soil organic carbon is strongly affected by the carbon economy of mycorrhizal symbioses. Our basic hypothesis is that the performance of nutrient acquisition by the mycorrhiza controls the carbon flux belowground. Regulation of carbon flux, depending on nutritional status, shall be studied in microcosm experiments. While strigolactone analysis will inform about the plant's stimulation of hyphal growth, the allocation of carbon in the soil-wide-web will be investigated by IRMS and nanoSIMS following a 13C labeling.

 

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Global comparison of the biogenic weathering rates of mycorrhiza

Supervisor:

Dr. Jens Boy, Dr. Robert Mikutta, Prof. Georg Guggenberger

Researcher:

Annika Dechêne

Duration:

2013-2016

Funded by:

Deutsche Forschungsgemeinschaft: DFG-Projekt (BO 3741 3-1)

Brief description:

Weathering is of utmost importance for the support of life on earth, as it delivers nutrients to organisms. Besides physico-chemical weathering, biogenic weathering might contribute substantially to overall mineral degradation and supply of nutrients to the ecosystem. Mycorrhizal fungi are increasingly identified to be a major player in biogenic weathering, but the underlying processes are still little understood as comparative in situ studies on large scale are lacking. This project aims at elucidating the biogenic weathering functioning of mycorrhizal fungi in a global field study by comparing forest ecosystems dominated by closely related plants either realizing arbuscular mycorrhiza (AM) or ectomycorrhiza (EM). Mesh bags containing minerals with different stability and nutrient contents are buried at 21 biogeochemically monitored sites for up to three years. Using multiple wet chemical, imaging, and spectroscopic methods we will assess (i) the extent of fungal colonization and type of mycorrhiza involved in mineral weathering, (ii) the selectivity, magnitude and rate of mycorrhiza-induced mineral weathering depending on ecosystem properties, and (iii) the contribution of different organism groups to biogenic weathering. This unique data set will largely extend our current understanding of the role of biota in ecosystem functioning and sustainability on global scale.

 

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KULUNDA: Ökologische und Ökonomische Strategien zur nachhaltigen Landnutzung in Russischen Steppen: Ein Beitrag zur Anpassung an den Klimawandel - Teilprojekt: Landnutzungseffekte für die Kohlenstoffsequestrierung in Steppenböden

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Robert Mikutta, Dr. Olga Shibistova

Researcher:

Norbert Bischoff

Duration:

2012-2016

Funded by:

Bundesministerium durch Bildung und Forschung (BMBF)

 

 

Mechanismen und Regulation der Kohlenstoffspeicherung in cryoturbaten Böden der Eurasischen Arktis

Supervisor:

Prof. Dr. Georg Guggenberger und Dr. Robert Mikutta

Researcher:

Dr. Olga Shibistova, Norman Gentsch

Duration:

2010-

Funded by:

European Science Foundation (ESF) / Bundesministerium für Bildung und Forschung (BMBF)

 

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NTH Graduate School GeoFluxes - Microbially-mediated transformation and mobilization of Fe-organic associations in the critical zone

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Robert Mikutta, Prof. Dr. Axel Schippers

Researcher:

Christine Poggenburg

Duration:

2012-2015

Funded by:

Niedersächsisches Ministerium für Wissenschaft und Kultur

 

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NTH Graduate School GeoFluxes - Natural organic matter turnover in peatlands as major driving factor for fluxes of DOM, nutrients, and trace elements

Supervisor:

Prof. Dr. Harald Biester (TU Braunschweig), Prof. Dr. Georg Guggenberger

Researcher:

Tanja Broder

Duration:

2012-2015

Funded by:

Niedersächsisches Ministerium für Wissenschaft und Kultur

 

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Past and present human impact on Kobresia pygmaea ecosystems as deduced from soil organic matter studies

Supervisor:

Prof. Dr. Georg Guggenberger und Prof. Dr. Yakov Kuzyakov (Universität Göttingen)

Researcher:

Lena Becker

Duration:

2009-2014

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

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Phototrophic community succession as driver of mineral weathering and soil formation along chronosequences in maritime Antarctica (SPP 1158 "Antarctic Research")

Supervisor:

Dr. Jens Boy, Dr. Robert Mikutta, Dr. Olga Shibistova, Prof. Dr. Georg Guggenberger, Prof. Dr. Roberto Godoy

Researcher:

Dr. Olga Shibistova, Ning Ning Zhao, Mauricio Aguirre Morales

Duration:

2013-2016

Funded by:

Deutsche Forschungsgemeinschaft: DFG-Projekt (BO 3741 2-1)

Brief description:

Weathering is of utmost importance for the support of life on earth, as it turns bedrock into soil and delivers nutrients to organisms. Vice versa, life itself is heavily engaged in mineral weathering by investment of photosynthates into weathering processes. We aim at investigating the processes and thresholds in biogenic weathering as a function of photoautotrophic community succession from microalgae/cyanobacteria to lichen-dominated stages towards the appearance of higher plants along soil chronosequences built by global-change induced glacier retreat in maritime Antarctica. For this, along the chronosequences weathering agents, organic carbon allocation to the soil, mineral in-situ composition and biogenic weathering on surfaces of introduced and defined, rock forming minerals will be assessed and related to phototrophic community structure. We expect to contribute to the understanding if and how life alters its own habitat in an extreme terrestrial ecosystem, and how this biogeosystem may respond to changes induced by Global Change in an increasingly warmer Antarctica.

 

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Plant-microbe strategies for utilization of mineral-associated P sources

Supervisor:

Prof. Dr. R. Mikutta, Prof. Dr. B. Glaser, Prof. Dr. G. Guggenberger

Duration:

2017-2019

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

[Translate to Englisch:] Depleted resources in easy accessible apatite as well as the sorption of inorganic and organic phosphorus (P) to secondary minerals are the main proposed aspects for P limitation of old weathered forest ecosystems. In spite of that indications exist that sorption of P is not irreversible and that life communities are capable to recycle mineral-associated P. But the underlying processes and controlling factors are still poorly known. In this project we will test the hypothesis that particularly in P-limited ecosystems plant-microbe communities can utilize mineral-bound P. We assume that a higher P use efficiency from secondary minerals, especially of sorbed orthophosphate in comparison to P monoesters, is due to an enhanced investment of photosynthates into weathering-active mycorrhiza and bacteria, with such a strategy being realized for both ectomycorrhized plants as well as for plants living in symbiosis with arbuscular fungi. Therefore, mesocosm experiments with soils varying in P supply and amended with additional P sources, i.e. ferrihydrite with adsorbed orthophosphate and P-monoesters, will be run under Fagus sylvatica (ectomycorrhiza) und Acer pseudoplatanus (arbuscular mycorrhiza). 13CO2 isotope labeling and substance-specific 13C analysis in phospholipid fatty acids and low-molecular weight organic acids as well as enzyme activity measurements will inform about the investment of plants into microbial communites as well as weathering agents as a function of soil P availability and P types present. In a field exposure experiment, P adsorption complexes will be buried and incubated for one year to verify the mesocosms results. Phosphorus losses will be assessed by X-ray fluorescence and photoelectron spectroscopy and the involved microbial communities will be described based on quantitative real-time PCR and 454 pyrosequencing. The obtained data will clarify whether the recycling of P from secondary minerals is a relevant process and which strategies of life are realized.

 

 

Process-based & Resilience-Oriented management of DIversity Generates sustainable Yields (PRODIGY) – a transnational project in the MAP-region (Brazil, Peru, Bolivia)

Supervisor:

Dr. Jens Boy, Prof. Dr. Guggenberger

Researcher:

Alberto Andrino de la Fuente

Duration:

2017-2018 (öpotentiell 2022)

Funded by:

BMBF, Programm: Kipppunkte, Dynamik und Wechselwirkungen von sozialen und ökologischen Systemen (BioTip)

Brief description:

It is widely accepted that biodiversity has to be conserved and thus became a Global Sustainable Development Goal (No. 15). Surprisingly little is known about the processes which are driven by biodiversity, the kinetics of these processes, their scale-dependency, systemic feedbacks as well as potential and already crossed tipping points. The reason for this is simple: biodiversity means complexity, thus many degrees of freedom to be covered for addressing its working principles. Further, impacts on- and consequences of- biodiversity-related processes might often be visible at a scale not investigated in a given study. Approaches of research fields are commonly linked to a certain scale. In order to overcome this system-inherent obstacle, our inter- and transdisciplinary working group commits itself strictly to a multivariate and multi-scale approach, where the steering of biodiversity on processes and their tipping points are likely to be understood at all relevant levels, also by tracking down unforeseen feedback loops overleaping scales We aim at the most crucial aspect of biodiversity in terms of successfully mainstreaming its value as a protectable good in the international decision process: advancing research on the valuation of biodiversity and its ecosystem services by linking social cost-benefit analysis to dynamic ecological-economic models that explicitly represent biodiversity as a functional component of the ecosystem. This will allow us to explore how policies and land(scape) management strategies can operationalize the conservation of biodiversity as a valuable asset for ensuring human livelihood and maintaining socio-ecological system resilience in the face of climate change and economic shocks. With this general understanding of biodiversity-driven processes and their effects on the socio-ecological system and economic value chains at hand, strategies and policies to avoid the crossing of the tipping points on the various scales can be developed. Thus, we understand that biodiversity is driving functional processes and determining tipping points, rather than being solely a victim of exceeded tipping points.

 

 

Skalierung von Sorptionsisothermen und physikochemischen Bodeneigenschaften zur Quantifizierung der Feldskaligen Variabilität der Retardation reaktiver Stoffe in Böden

Supervisor:

Prof. Dr. Jürgen Böttcher

Researcher:

Han Xiao

Duration:

2010-2015

 

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Soil-age driven inverse coupling of biogenic weathering and nutrient recycling on ecosystem level.

Supervisor:

Prof. Dr. Roberto Godoy, Dr. Jens Boy

Researcher:

Cesar Andres Marin Daza

Duration:

2014-2017

Funded by:

Fondo Nacional de Desarollo Cientifico y Tecnologico (FONDECYT)

 

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Spatiotemporal interactions of aggregate-forming agents within soil microaggregates: Consequences for aggregate structure and stability

Supervisor:

Prof. Dr. Georg Guggenberger, Dr. Robert Mikutta

Researcher:

Dr. Stefan Dultz, Dr. Susanne K. Woche

Duration:

2015-2018

Funded by:

DFG Research Unit 2179: MAD Soil - Microaggregates: formation and turnover of the structural building blocks of soils

Brief description:

Aggregation in soil is a very dynamic, multi-cause process, with changes in aggregate architecture having major implications for many soil functions, e.g., water storage and transport, aeration, biological activity, and the storage and cycling of organic carbon. In the project we relate the abundance and interactions of the various aggregate-forming agents (AFA) present in smaller building units (BU) and soil microaggregates (SMA) to the overall structure, mineralogical composition, and pore size distribution of microaggregates. Our basic assumption is that microaggregation is controlled by surface properties of participating AFA such as clay minerals, Fe- and Al-oxides and organic matter. The role of surface charge on the formation of BU and SMA is determined in model experiments. Furthermore we assume that the composition of organic matter at outer particle and aggregate surfaces determines the ability to form mineral-organic-mineral bonds and thus influence the stability of microaggregates. Here our central approach is to utilize X-ray photoelectron spectroscopy (XPS) to characterize the surface chemical composition of model BU and SMA within a 2-10 nm thin surface layer. Changing soil environmental conditions (pH, Eh, ionic strength) might vary in space and in time and can make AFA to lose their aggregating function. Organic matter initiating aggregate formation can be removed by desorption and microbial consumption, resulting in destabilization of aggregates. In summary, our work program addresses four different issues: (1) overall structure, mineralogical composition, and pore size distribution of microaggregates, (2) temporal change and spatial distribution of elements within microaggregates, (3) quality and stability of microaggregate-entrained OM, and (4) stability of microaggregates upon selective removal of AFA.

 

 

SPICE III Indonesia: TIMES – Terrestrial Influences on Mangrove Ecology and Sustainability of their resources - Carbon sequestration as a function of land use change in mangroves

Supervisor:

Dr. Jens Boy, Dr. Robert Mikutta, Prof. Dr. Georg Guggenberger

Researcher:

Christian Weiss, Joanna Weiss

Duration:

2012-2016

Funded by:

Bundesministerium für Bildung und Forschung (BMBF)

Brief description:

This project aims at understanding the processes of carbon (C) sequestration in representative mangrove ecosystems in Indonesia (Segara Anakan Lagoon, Java, Togian Islands, Sulawesi, Berau, Kalimantan) as a function of mangrove conversion, in order to develop and test an easy-to-use tool for pricing of C related environmental services (CRES) in REDD and PES schemes. We will investigate into the C sequestration potential of mangrove by linking C stocks to sources, composition, and turnover of organic matter (OM) species in soil. Furthermore, we aim to clarify to which extent these functions are triggered by plant and microorganisms (bacteria and fungi) species composition in pristine and used (including completely deforested) mangroves. This process-based understanding of utilization thresholds is a prerequisite for successful future management scenarios dealing with C sequestration in mangrove ecosystems. Moreover, it will be tested whether identification of aboveground species composition could act as a valid indicator for CRES, both in economically based decision making on broader scale and local cost-efficient monitoring of the consecutive provision of CRES.

 

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Untersuchung der physikochemischen und mechanischen Eigenschaften von vulkanischen Ascheböden in Südchile und der Konsequenzen für die daraus resultierende Erodibilität

Supervisor:

Prof. Dr. Jörg Bachmann

Researcher:

Jiem Krüger

Duration:

2010-2013

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

 

 

Untersuchungen zur Rolle unterschiedlicher Agroforstbäume für Produktion von Coffea arabica L. in der Gedeo Zone Süd-Äthiopiens

Supervisor:

Prof. Dr. Georg Guggenberger

Duration:

2007-

 

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When nano-scale meets biodiversity: retention and recycling mechanisms of organic phosphorus in soil (SPP 1685 "Ecosystem Nutrition: Forest Strategies for limited Phosphorus Resources")

Supervisor:

Dr. Robert Mikutta, Dr. Jens Boy, Prof. Dr. Georg Guggenberger

Researcher:

Dennis Lorenz

Duration:

2013-2016

Funded by:

Deutsche Forschungsgemeinschaft: DFG-Projekt (MI 1377/7-1)

Brief description:

Soil organic matter is considered to become an increasingly important source of bioavailable phosphorus (P) with depletion of inorganic P within primary minerals. Current concepts on P cycling and mobilization of organic P largely ignore the formation of mineral-organic associations. This project aims to link processes occurring at the nanoscale on mineral surfaces with the bioavailability of organic P, with particular focus on the influence of biodiversity and establishment of functional niches by microbial communities on P recycling in soils. Along a soil P availability gradient the proportion of mineral-associated P as well as its composition (31P NMR and X-ray absorption near edge structure spectroscopy) will be determined and related to mineralogical soil properties. Based on adsorption and desorption experiments using both, monomeric and polymeric P sources, the recycling potential of mineral-bound organic P by various biotic communities (plants, mycorrhiza, bacteria) will be determined in mesocosm and field experiments. We expect to assess the relevance of mineral-associated organic P for the P recycling of forest ecosystems and to identify the major controlling abiotic and biotic variables.

 

 

„Peat substitutes in growing media“ – Development of a tool for the decision making process in identifying peat substitutes for growing media warranting high quality standards in horticultural crop production

Supervisor:

Prof. Dr. Jürgen Böttcher, Prof. Dr. Heike Bohne

Researcher:

Dr. Katharina Leiber-Sauheitl

Duration:

2016-2019

Funded by:

Deutsche Bundestiftung Umwelt (DBU)

Brief description:

Mining of peat as a raw material for the production of growing media and potting soil is associated with major ecological problems: greenhouse gas emissions, alteration of the landscape, loss of biological diversity, changes of the water supply on a landscape scale. Peat substitutes in growing media such as e.g. composted bark, wood and coconut fibres are added only in small proportions so far since they have different properties as peat and therefore, they can cause risks in crop production. Moreover, they are not available in sufficient amounts so far and can also result in ecological problems (e.g. energy-consuming transportation of coconut fibre). Therefore, the main objective of this project is the development of a tool for the decision making process by which new raw materials as peat substitutes in growing media and their potential risks in crop production can be identified as well as provisions for a safe cultivation can be suggested. For this, analytical methods for the characterization of the chemical, physical and microbiological properties of raw materials and potential new growing media components are further developed in cooperation with the processing industry (processing of raw materials / composting, production of growing media). Obtained results are verified by experiments with horticultural crops in companies of different sections of commercial horticulture.