Kai Uwe Totsche

Kai Uwe Totsche
Friedrich Schiller University Jena | FSU · Institute of Geoscience, Department of Hydrogeology

University-Professor Dr.

About

258
Publications
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Introduction
Kai Uwe Totsche is Professor and head of the Department of Hydrogeology at the Institute of Geoscience, Friedrich Schiller University Jena, Germany. Kai and his group does research in Nanobiogeochemistry, Environmental Chemistry, Subsurface Critical Zone Research and (Ground-) Water Science. The research approach comprises field (in-situ), lab (in-vitro) and numerical (in-silico) methods. Focus is on structure-function relationships, interaction and reaction at biogeochemical interfaces in natural porous media, origin and fate of mobile (organic) matter including microorganimsms. Special emphasis is put on the vastly ignored colloidal and suspended particle fraction of organic, mineral and biotic origin. Current projects are among others 'AquaDiva' and 'MAD Soil'

Publications

Publications (258)
Article
Full-text available
Earthworms and (tap-)roots impact the soil structure by creating large biopores, affecting infiltration capacity, seepage, nutrient cycling, and soil aeration. Despite the importance of biopores for the functions of soils and the fact that several hundreds of biopores >2 mm in diameter may occur on one square meter of soil, knowledge on the interde...
Preprint
Full-text available
Analysis of 5 years metabolomics data for groundwater, at 7 sampling sites across a hillslope aquifer system. The study uses particularly principal component analysis (PCA) of LCMS-data to show that the highly variable metabolome is driven by water flows, and traces those in inter-well comparisons.
Article
Microaggregates are hot spots of microbial activity at a scale that frequently poses a severe experimental challenge or defies a direct observation. Mathematical models that combine the mechanisms of spatially resolved organic matter transport with the processes of organic matter turnover can facilitate the understanding of soil microbial dynamics...
Preprint
3-hourly Net Ecosystem Exchange (NEE) is estimated at spatial scales of 0.25 degrees over the European continent, based on the pre-operational inverse modelling framework CarboScope Regional (CSR) for the years 2006 to 2019. To assess the uncertainty originating from the choice of a-priori flux models and observational data, ensembles of inversions...
Article
Full-text available
Soil organisms are recognized as ecosystem engineers and key for aggregation in soil due to bioturbation, organic matter (OM) decomposition, and excretion of biogenic OM. The activity of soil organisms is beneficial for soil quality, functions, and nutrient cycling. These attributions are based on field-scale observations that link the presence and...
Article
Full-text available
Temporal evolution of element ratios in the catchment of the River Thuringian Saale A literature retrieval was performed for a total of about 5491 datasets of whole rock geochemical analyses of sedimentary, magmatic and metamorphic rocks in the catchment of River Thuringian Saale for the past 600 Ma. Considering availability and coincidence with p...
Article
Full-text available
Engineered humic acid-coated goethite (HA-Goe) colloids find increasing application in in situ remediation of metal(loid)-polluted groundwater. Once introduced into the subsurface, the colloids interact with groundwater altering their physicochemical properties. In comparison to freshly synthesized, unreacted HA-Goe colloids, such alterations could...
Article
Time series analyses are a crucial tool for uncovering the patterns and processes shaping microbial communities and their functions, especially in aquatic ecosystems. Subsurface aquatic environments are perceived to be more stable than surface oceans and lakes, due to the lack of sunlight, the absence of photosysnthetically-driven primary productio...
Preprint
Full-text available
Mathematical models that combine the mechanisms of organic matter transport in a pore space with the processes of organic matter turnover can facilitate the understanding of soil microbial dynamics and function of soils at scales still inaccessible for experiments. In this study, we investigate microbial population dynamics and the turnover of par...
Preprint
Full-text available
Time series analyses are a crucial tool for uncovering the patterns and processes shaping microbial communities and their functions, especially in aquatic ecosystems. Subsurface aquatic environments are perceived to be more stable than oceans and lakes, due to the lack of sunlight, the absence of photosysnthetically-driven primary production, low t...
Article
Full-text available
Colloidal settlement in natural aqueous suspensions is effectively compensated by diffusive movement if particles resist aggregation – a state known as colloidal stability. However, if the settling velocity increases upon aggregation, complex structural features emerge from the directional movement induced by gravity. We present a comprehensive mod...
Article
Full-text available
Surface-sourced organic compounds in infiltrating waters and percolates are transformed during their belowground passage. Biotic and abiotic processes thereby lead to continuously changing chemical environments in subsurface compartments. The investigation of such transformations of organic compounds aims for tracing subsurface fluxes as well as bi...
Article
Full-text available
Hypothesis A prominent fraction of mobile organic matter in natural aqueous soil solutions is formed by molecules in sizes that seamlessly exceed the lower end of what is defined as a colloid. The hydrodynamics and the functional diversity of these molecules result in a transport behavior that is fundamentally different from smaller compounds. Howe...
Article
Full-text available
Considerable portions of the total mobile inventory of soil seepage are the diverse colloidal and larger suspended materials that essentially contribute to pedogenesis, soil functioning, and nutritional supply of subsurface ecosystems. However, the size- and material-spectra of the total mobile inventory, and field-scale factors controlling its lon...
Article
Full-text available
Forecasting atmospheric CO2 concentrations on synoptic timescales (∼ days) can benefit the planning of field campaigns by better predicting the location of important gradients. One aspect of this, accurately predicting the day-to-day variation in biospheric fluxes, poses a major challenge. This study aims to investigate the feasibility of using a d...
Article
Full-text available
Earthworms are considered as “ecosystem engineers” impacting soil properties as well as nutrient and element cycles. As they move through soil, earthworms secrete cutaneous mucus which is metabolized by soil microorganisms and a source of plant-available nutrients. Earthworm-processed soil contains carbon enriched, earthworm-specific soil aggregate...
Article
High inputs of easily available organic matter to the subsurface may quickly activate the native microbial communities, thereby changing soil engineering properties. We studied the effect of glucose addition, an easily available carbon source, on stress-strain properties, mineralogy, and microstructure of several loamy and sandy soils over 30 days...
Poster
Full-text available
Anthropogenic inputs of nitrate into groundwater pose a considerable risk to drinking water quality. However, groundwater chemistry is also affected by continued in situ microbial nitrate formation and nitrate reduction to gaseous nitrogen. Here, we investigated nitrogen transformation processes and their microbial key players in oligotrophic karst...
Article
Full-text available
Soil functions are closely related to the structure of soil microaggregates. Yet, the mechanisms controlling the establishment of soil structure are diverse and partly unknown. Hence, the understanding of soil processes and functions requires the connection of the concepts on the formation and consolidation of soil structural elements across scales...
Article
Full-text available
Surface ecosystems are rapidly changing on a global scale and it is important to understand how this influences aquifers in the subsurface, as groundwater quality is a major concern for future generations. Dissolved organic matter (DOM) contains molecular and isotopic signals from surface-derived inputs as well as from the biotic and abiotic subsur...
Article
Full-text available
Groundwater ecosystems face the challenge of energy limitation due to the absence of light-driven primary production. Lack of space and low oxygen availability might further contribute to generally assumed low food web complexity. Chemolithoautotrophy provides additional input of carbon within the subsurface, however, we still do not understand how...
Article
Hydrodynamics drives both stochastic and deterministic community assembly in aquatic habitats, by translocating microbes across geographic barriers and generating changes in selective pressures. Thus, heterogeneity of hydrogeological settings and episodic surface inputs from recharge areas might play important roles in shaping and maintaining groun...
Article
Multi-directional fluid flow and transport dynamics as intrinsic characteristics of hillslope flow regimes can strongly contribute to the quality evolution of groundwater resources and compartmentalization of subsurface ecosystems. However, their extent and importance in topographic highs (groundwater recharge areas) is typically less investigated,...
Article
Full-text available
Forecasting atmospheric CO2 concentrations on synoptic time scales (~ days) can benefit the planning of field campaigns by better predicting the location of important gradients. One aspect of this, accurately predicting the day-to-day variation in biospheric fluxes poses a major challenge. This research aims to investigate the feasibility of using...
Article
Full-text available
Despite the widely observed predominance of Cand. Patescibacteria in subsurface communities, their input source and ecophysiology are poorly understood. Here we study mechanisms of the formation of a groundwater microbiome and the subsequent differentiation of Cand. Patescibacteria. In the Hainich Critical Zone Exploratory, Germany, we trace the in...
Article
Full-text available
Across a landscape, aquatic-terrestrial interfaces within and between ecosystems are hotspots of organic matter (OM) mineralization. These interfaces are characterized by sharp spatio-temporal changes in environmental conditions, which affect OM properties and thus control OM mineralization and other transformation processes. Consequently, the exte...
Article
Vein mineralization observed in boreholes, quarries and outcrops of Upper Permian and Mesozoic sediments in the Thuringian Syncline, Germany, was investigated for the first time by petrography, electron microprobe analysis and stable isotope analysis. The objective was a characterization of paleo-fluid systems within this basin. Veins are mostly re...
Conference Paper
Full-text available
Finding interlinkages between soil chemistry, microstructure and microbial communities in the contaminated soils is a fundamental requirement to assess their remediation strategy. We studied composition, microstructure and microbial communities of an aged tar oil contaminated technosol on a former manufactured gas plant site in Germany. The soil co...
Article
Terrestrial subsurface microbial communities are not restricted to the fluid-filled void system commonly targeted during groundwater sampling but are able to inhabit and dwell in rocks. However, compared to the exploration of the deep biosphere, endolithic niches in shallow sedimentary bedrock have received little interest so far. Despite the poten...
Article
Full-text available
Despite the global significance of the subsurface biosphere, the degree to which it depends on surface organic carbon (OC) is still poorly understood. Here, we compare stable and radiogenic carbon isotope compositions of microbial phospholipid fatty acids (PLFAs) with those of in situ potential microbial C sources to assess the major C sources for...
Article
Full-text available
Determining the biogeochemical pathways utilized by microbes living in groundwater is essential for understanding the subsurface C cycle and the fate of organic compounds, including pollutants. The radiocarbon signature (Δ ¹⁴ C) of fatty acid methyl esters derived from microbial phospholipids (PLFA) provides useful information for differentiating m...
Article
Full-text available
The functions of soils are intimately linked to its aggregated structure. Microaggregates formed during pedogenesis from a vast variety of mineral, organic, and biotic materials are the smallest conceivable compounds at the basis of soil structural hierarchy. Qualitative hypotheses and concepts on how aggregates form are quite elaborate, but the co...
Conference Paper
An intensive flight campaign, CoMet (Carbon dioxide and Methane Mission), was conducted during May and June 2018, with the aim to better understand important sources of carbon dioxide (CO2) and methane (CH4) in Europe as well as to test and validate the newly developed Integrated Path Differential Absorption (IPDA) Lidar CHARM-F operated by DLR. On...
Article
Full-text available
Structures of colloidal compounds in soil, including organo–mineral and mineral–mineral associations, are considered as composite building units (CBUs) that may combine into soil microaggregates. Despite the ubiquitous occurrence of CBUs, the major formation mechanisms are rather obscure and little is known about whether they form primarily during...
Article
Structural hierarchy is a fundamental characteristic of natural porous media. Yet it provokes one of the grand challenges for the modeling of fluid flow and transport since pore‐scale structures and continuum‐scale domains often coincide independent of the observation scale. Common approaches to represent structural hierarchy build, for example, on...
Article
Groundwater ecosystems host diverse and complex microbial communities that play important roles in the biogeochemical processing of organic matter and in the maintenance of drinking water quality. Here we investigated the microbial community in suspended particulate matter (SPM) of biogeochemically distinct groundwaters (Hainich Critical Zone Explo...
Article
Full-text available
Structure formation and self organization in soils determine soil functions and regulate soil processes. Mathematically based modeling can facilitate the understanding of organizing mechanisms at different scales, provided that the major driving forces are taken into account. In this research we present an extension of the mechanistic model for tra...
Article
Organic particles including microorganisms are a significant fraction of the mobile organic matter (MOM) pool that contributes to initial pedogenesis. Still, the dynamics and the interplay of the multitude of processes that control the mobilization, transport, and retention of MOM are vastly unclear. We studied this interplay using an ‘artificial s...
Article
Substantial amounts of organic matter are mobilized from upper soil layers during extreme precipitation events. This results in considerable fluxes of carbon from plant-associated topsoil to deeper mineral soil and to groundwater. Microbes constitute an important part of this mobile organic matter (MOM) pool. Previous work has shown that specific b...
Article
Fourier-transform infrared (FTIR) spectra of environmental samples usually comprise superposed pure component spectra of the individual constituents present. Thus, evaluation of band intensities and reconstruction of FTIR spectra by inverse techniques is often prone to ambiguity. Frequently applied multivariate curve resolution techniques (PCA, PCR...
Article
Full-text available
Airborne measurements of CO2, CO, and CH4 proposed in the context of IAGOS (In-service Aircraft for a Global Observing System) will provide profiles from take-off and landing of airliners in the vicinity of major metropolitan areas useful for constraining sources and sinks. A proposed improvement of the top-down method to constrain sources and sink...
Article
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Although fungi play important roles in biogeochemical cycling in aquatic ecosystems and have received a great deal of attention, much remains unknown about the living fractions of fungal communities in aquifers of the terrestrial subsurface in terms of diversity, community dynamics, functional roles, the impact of environmental factors and presence...
Article
A combined study of facies and diagenesis variations was carried out with the aim to understand small-scale heterogeneities in porosity and permeability of sandstones within a 219 m completely cored Middle Buntsandstein succession from central Germany. The well Erfurt 1/12 (EF-FB 1/12) allows studying aquifer quality variations by taking 49 plug sa...
Article
Full-text available
The quality of near-surface groundwater reservoirs is controlled, but also threatened, by manifold surface–subsurface interactions. Vulnerability studies typically evaluate the variable interplay of surface factors (land management, infiltration patterns) and subsurface factors (hydrostratigraphy, flow properties) in a thorough way, but disregard t...
Article
Full-text available
Despite the high relevance of anaerobic ammonium oxidation (anammox) for nitrogen loss from marine systems, its relative importance compared to denitrification has less been studied in freshwater ecosystems, and our knowledge is especially scarce for groundwater. Surprisingly, phospholipid fatty acids (PLFA)-based studies identified zones with pote...
Conference Paper
Full-text available
Tar-oil is a waste product of coal carbonization on manufactured gas plants. It is one of the main hydrocarbon soil contaminant in Europe and North America. We studied the soil on one of the former plant"s basin. On the macroscale, the contaminant seemed to be evenly distributed. On the microscale, tar-oil was heterogeneously concentrated in some o...
Article
Full-text available
Isotopes of dissolved inorganic carbon (DIC) are used to indicate both transit times and biogeochemical evolution of groundwaters. These signals can be complicated in carbonate aquifers, as both abiotic (i.e., carbonate equilibria) and biotic factors influence the δ¹³C and ¹⁴C of DIC. We applied a novel graphical method for tracking changes in the...
Article
Full-text available
All soils harbor microaggregates, i.e., compound soil structures smaller than 250 µm. These microaggregates are composed of diverse mineral, organic and biotic materials that are bound together during pedogenesis by various physical, chemical and biological processes. Consequently, microaggregates can withstand strong mechanical and physicochemical...
Article
Full-text available
Oxygen and nitrate availability as well as the presence of suitable organic or inorganic electron donors are strong drivers of denitrification; however, the factors influencing denitrifier abundance and community composition in pristine aquifers are not well understood. We explored the denitrifier community structure of suspended and attached groun...