Andreas Kappler

Andreas Kappler
University of Tuebingen | EKU Tübingen · Department of Geosciences

Ph.D.

About

494
Publications
145,676
Reads
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21,019
Citations
Citations since 2016
247 Research Items
14953 Citations
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201620172018201920202021202205001,0001,5002,0002,500
201620172018201920202021202205001,0001,5002,0002,500
201620172018201920202021202205001,0001,5002,0002,500
Additional affiliations
August 2002 - August 2004
California Institute of Technology
Position
  • PostDoc Position
October 2000 - August 2002
Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
Position
  • PostDoc Position
September 1997 - October 2000
Universität Konstanz
Position
  • PhD Student

Publications

Publications (494)
Article
Arsenic (As)-bearing water treatment residuals (WTRs) from household sand filters are usually disposed on top of floodplain soils and may act as a secondary As contamination source. We hypothesized that open disposal of these filter-sands to soils will facilitate As release under reducing conditions. To quantify the mobilization risk of As, we incu...
Preprint
Full-text available
The drinking water quality of millions of people in South and Southeast Asia is at risk due to arsenic (As) contamination of groundwater and insufficient access to water treatment facilities. Intensive use of nitrogen (N) fertilizer increases the possibility of nitrate (NO 3 ⁻ ) leaching into aquifers, yet very little is known about how the N cycle...
Article
Full-text available
elemental sulfur was the dominant product of sulfide oxidation (~ 50 to 75% of oxidized sulfur), thiosul-fate was the second most abundant product accounting for ~ 20% of the oxidized sulfide. The incorporation of S into PPHS' organic structure was revealed by the formation of methylthio, ethylthio, thiol, and aromatic-disulfide/polysulfide moietie...
Conference Paper
Hydrothermal sulfide systems are among the most ancient habitats on Earth and are widely considered potential sites for the emergence of life. Deposits from such settings are thus of great evolutionary significance, but the geobiology of our planet’s most ancient hydrothermal sulfide systems remains largely unexplored. This is mainly due to a limit...
Preprint
Full-text available
Microbial electrosynthesis is an emerging biosynthesis technology that produces value-added chemicals and fuels and, at the same time, reduces the environmental carbon footprint. However, constraints, such as low current densities and high inner resistance, disfavor this technology for industrial-scale purposes. The cathode performance has been str...
Article
Full-text available
Incineration is one of the key technologies in disposal of municipal waste, which produces municipal solid waste incineration (MSWI) residues with high valuable metal contents. The recycling strategy for the MSWI residues is typically focused on the recovery of scrap metals yielding processed municipal solid waste incineration residues (PIR) as the...
Article
Short-range-ordered Fe(III) minerals such as ferrihydrite (Fh) are ubiquitous in the environment, are key players in biogeochemical cycling, and sorb trace elements and nutrients. As such, it is important to be able to identify the presence of such minerals in natural samples. Fh is commonly observed to be X-ray amorphous and cannot be easily analy...
Article
Full-text available
Natural-abundance measurements of nitrate and nitrite (NOx) isotope ratios (𝛿15N and 𝛿18O) can be a valuable tool to study the biogeochemical fate of NOx species in the environment. A prerequisite for using NOx isotopes in this regard is an understanding of the mechanistic details of isotope fractionation (15𝜀, 18𝜀) associated with the biotic and a...
Article
We report an unrecognized, tidal source of reactive oxygen species (ROS). Using a newly developed ROS-trapping gel film, we observed hot spots for ROS generation within ∼2.5 mm of coastal surface soil. Kinetic analyses showed rapid production of hydroxyl radicals (•OH), superoxide (O2•-), and hydrogen peroxide (H2O2) upon a shift from high tide to...
Article
Microbially mediated Fe(II) oxidation is one of the most important pathways of Fe redox cycling on both present and early Earth. It was proposed to participate in iron formations (IFs) deposition under oxygen-depleted oceanic conditions before the Great Oxidation Event (GOE). Fe isotopic records in IFs provide important archives for the redox state...
Article
Full-text available
Biochar can mediate extracellular electron transfer (EET) of Shewanella oneidensis MR-1 and subsequently facilitate dissimilatory reduction of iron(III) minerals. Previous studies mainly focused on the interaction of biochar and membrane cytochrome complexes to reveal the mediating mechanisms between biochar and S. oneidensis MR-1. However, the inf...
Article
Glacial melt-down alters hydrological and physicochemical conditions in downstream aquatic habitats. In this study we tested if sediment associated microbial communities respond to the decrease of glaciers and associated meltwater flows in high-alpine lakes. We analysed 16 lakes in forefield catchments of three glaciers in the Eastern Swiss Alps on...
Preprint
Banded Iron Formations (BIFs) have long been considered a sedimentary record of seawater trace metal composition during the Precambrian. However, recent work has suggested that the trace metal composition of BIFs was derived from phytoplankton biomass, not seawater. In this model, phytoplankton biomass settles from the photic zone to the seafloor s...
Article
Full-text available
In urban ecosystems, nutrient stocks, such as carbon (C), nitrogen (N), and phosphorus (P), are anthropogenically being enriched for material and energy supply. The overloaded nutrients have adverse ecological consequences, such as causing eutrophication of waters and soil in urban areas. Studying the ecophysiology of nutrient-cycling microbes in u...
Article
Household sand filters (SFs) are widely applied to remove iron (Fe), manganese (Mn), arsenic (As), and ammonium (NH4⁺) from groundwater in the Red River delta, Vietnam. Processes in the filters probably include a combination of biotic and abiotic reactions. However, there is limited information on the microbial communities treating varied groundwat...
Article
The generation of reactive oxygen species (ROS) mediated by minerals and/or microorganisms plays a vital but underappreciated role in affecting carbon and nutrient cycles at soil-water interfaces. It is currently unknown which interactions between microbial communities and iron (Fe) minerals produce hydroxyl radical (HO•), which is the strongest ox...
Article
Full-text available
NRFeOx microorganisms are globally distributed in various types of environments and play a vital role in iron transformation and nitrate and heavy metal removal. However, most known NRFeOx microorganisms were isolated from freshwater and marine environments, while their identity and activity under hypersaline conditions remain unknown.
Article
In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequen...
Article
Banded Iron Formations (BIFs) are ancient marine chemical sediments that contain various Fe-bearing minerals such as hematite (Fe2O3), magnetite (Fe3O4), siderite (FeCO3) and a variety of FeII-/FeIII-silicates. The prevailing opinion is that primary Fe(III) (oxyhydr)oxides, such as ferrihydrite (simplified formula of Fe(OH)3), were precipitated fro...
Conference Paper
Full-text available
The determination of various fuel properties is essential for an optimised operation of wood-fired heat (and power) plants and fair fuel trade. Besides the main parameters such as water content, ash content, and calorific value, the chemical composition is also important. The analysis is usually not performed at the heat (and power) plant directly,...
Poster
Full-text available
The determination of various fuel properties is essential for an optimised operation of wood-fired heat (and power) plants and fair fuel trade. Besides the main parameters such as water content, ash content, and calorific value, the chemical composition is also important. The analysis is usually not performed at the heat (and power) plant directly,...
Article
Full-text available
Reductive dissolution during permafrost thaw releases iron-bound organic carbon to pore-waters, rendering previously stable carbon vulnerable to microbial decomposition and subsequent release to the atmosphere. How mineral iron stability and the microbial processes influencing mineral dissolution vary during transitional permafrost thaw are poorly...
Article
Full-text available
In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO2 and CH4. During the summer, shifts in runoff and soil moisture influence redox condit...
Article
Iron(III) photoreduction is an important source of Fe(II) in illuminated aquatic and sedimentary environments. Under oxic conditions, the Fe(II) can be re-oxidized by oxygen (O2) forming reactive O-species such as hydrogen peroxide (H2O2) which further react with Fe(II) thus enhancing Fe(II) oxidation rates. However, it is unknown by aquatic sedime...
Article
To achieve a sustainable circular economy for wood ash, the reuse of wood ash in agriculture and forestry is important. To evaluate the usability of ash from the combustion of natural as well as waste wood for application as fertilizer, wood fuel and corresponding ash fraction samples (n = 86) of four industrial wood-fired heat and power plants (>2...
Article
Full-text available
Iron(II) [Fe(II)] oxidation coupled to denitrification is recognized as an environmentally important process in many ecosystems. However, the Fe(II)-oxidizing bacteria (FeOB) dominating autotrophic nitrate-reducing Fe(II)-oxidizing enrichment cultures, affiliated with the family Gallionellaceae, remain poorly taxonomically defined due to lack of re...
Article
Iron(II) (Fe(II)) can be formed by abiotic Fe(III) photoreduction, particularly when Fe(III) is organically complexed. Light-influenced environments often overlap or even coincide with oxic or microoxic geochemical conditions, for example, in sediments. So far, it is unknown whether microaerophilic Fe(II)-oxidizing bacteria are able to use the Fe(I...
Preprint
In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO2 and CH4. During the summer, shifts in runoff and soil moisture influence redox condit...
Article
Full-text available
In the mining-impacted Rio Tinto, Spain, Fe-cycling microorganisms influence the transport of heavy metals (HMs) into the Atlantic Ocean. However, it remains largely unknown how spatial and temporal hydrogeochemical gradients along the Rio Tinto shape the composition of Fe-cycling microbial communities and how this in turn affects HM mobility. Usin...
Article
Full-text available
Banded Iron Formations (BIFs) are marine chemical sediments consisting of alternating iron (Fe) - rich and silica (Si)-rich bands which were deposited throughout much of the Precambrian era. BIFs represent important proxies for the geochemical composition of Precambrian seawater and provide evidence for early microbial life. Iron present in BIFs wa...
Preprint
Laboratory-based studies on microbial Fe(II) oxidation are commonly performed over just a few weeks in small volumes with high substrate concentrations, resulting in geochemical gradients and volumetric effects caused by sampling. We used a chemostat to enable uninterrupted supply of medium, and investigated autotrophic growth of the nitrate-reduci...
Article
Fe(II) oxidation coupled to nitrate reduction is a widely observed metabolism. However, to what extent the observed Fe(II) oxidation is driven enzymatically or abiotically by metabolically produced nitrite remains puzzling. To distinguish between biotic and abiotic reactions, we cultivated the mixotrophic nitrate-reducing Fe(II)-oxidizing Acidovora...
Article
Full-text available
Autotrophic nitrate reduction coupled to Fe(II) oxidation is an important nitrate removal process in anoxic aquifers. However, it remains unknown how changes of O2 and carbon availability influence the community structure of nitrate-reducing Fe(II)-oxidizing (NRFeOx) microbial assemblages and what the genomic traits of these NRFeOx key players are....
Article
Full-text available
Autotrophic nitrate reduction coupled to Fe(II) oxidation is an important nitrate removal process in anoxic aquifers. However, it remains unknown how changes of O 2 and carbon availability influence the community structure of nitrate-reducing Fe(II)-oxidizing (NRFeOx) microbial assemblages and what the genomic traits of these NRFeOx key players are...
Article
In freshwater wetlands, redox interfaces characterized by circumneutral pH, steep gradients in O2, and a continual supply of Fe(II) form ecological niches favorable to microaerophilic iron(II) oxidizing bacteria (FeOB) and the formation of flocs; associations of (a)biotic mineral phases, microorganisms, and (microbially-derived) organic matter. On...
Article
Geobatteries are redox-active substances that can take up, store, and release electrons reversibly. Provided that their redox activity can be maintained by fluctuations of oxidizing and reducing redox conditions, geobatteries could also improve the performance of engineered systems, such as in biological nitrogen removal from wastewater or construc...
Article
Biochar can participate in biogeochemical electron transfer processes due to its electron-accepting and donating capabilities (i.e., geobattery) and electron conductivity (i.e., geoconductor). These two functions were separately demonstrated to play a role in biogeochemical iron cycling and methane formation. Yet, little is known about the coupled...
Preprint
Anoxygenic phototrophic Fe(II)-oxidizers (photoferrotrophs) are thought to have thrived in Earth’s ancient ferruginous oceans and played a primary role in the precipitation of Archean and Paleoproterozoic (3.8-1.85 Ga) banded iron formations (BIF). The end of BIF deposition by photoferrotrophs has often been interpreted as being the result a deepen...
Preprint
In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequen...
Article
There is longstanding controversy about the genesis of magnetite in banded iron formations (BIFs), particularly concerning whether it is of abiogenic or biogenic origin. The composition of trace elements within magnetite produced by magnetotactic bacteria has been proposed as a promising marker for its biological origin; however further experimenta...
Article
Ratios of phosphorous (P) to iron (Fe) in Precambrian banded iron formations (BIFs) have previously been used to estimate dissolved seawater phosphate concentrations in the ancient oceans. Such studies rely on an assumed composition of the primary iron minerals, the concentrations of the major ions in seawater, and empirical partitioning coefficien...
Article
Co-sorption of metal ions and anions/ligands at the mineral–water interface plays a critical role in regulating the mobility, transport, fate, and bioavailability of these compounds in natural environments. This review focuses on co-sorption of metal ions and naturally occurring anions/ligands on environmentally relevant minerals. The underlying me...
Preprint
Reactive iron (Fe) minerals can preserve organic carbon (OC) in soils overlying intact permafrost. With permafrost thaw, reductive dissolution of iron minerals releases Fe and OC into the porewater, potentially increasing the bioavailability of OC for microbial decomposition. However, the stability of this so-called rusty carbon sink, the microbial...
Article
Full-text available
Although arsenic (As) groundwater contamination in South and Southeast Asia is a threat to human health, mechanisms of its release from sediment to groundwater are still not fully understood. In many aquifers, Fe(III) minerals are often the main hosting phases for As and their stability is crucial for As mobility. Recently, a new mechanism for As m...
Article
Neutrophilic microbial pyrite (FeS 2) oxidation coupled to denitrification is thought to be an important natural nitrate attenuation pathway in nitrate-contaminated aquifers. However, the poor solubility of pyrite raises questions about its bioavailability and the mechanisms underlying its oxidation. Here, we investigated direct microbial pyrite ox...
Preprint
Full-text available
Reactive iron (Fe) minerals can preserve organic carbon (OC) in soils overlying intact permafrost. With permafrost thaw, reductive dissolution of iron minerals releases Fe and OC into the porewater, potentially increasing the bioavailability of OC for microbial decomposition. However, the stability of this so-called rusty carbon sink, the microbial...
Conference Paper
Full-text available
The cultivation of rice as a staple food for millions of people will be intensified in the future to meet the global food demand arising from a growing population. Nitrogen fertilizers are commonly applied to paddy fields to increase rice yield, but also stimulate microbial (de-)nitrification, leading to intermediates such as nitrous oxide (N2O), t...
Article
Full-text available
Fe(II) oxidation coupled to nitrate reduction (NRFO) has been described for many environments. Yet very few autotrophic microorganisms catalysing NRFO have been cultivated and their diversity, as well as their mechanisms for NRFO in situ remain unclear. A novel autotrophic NRFO enrichment culture, named culture BP, was obtained from freshwater sedi...
Article
Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this...
Article
Nitrate removal in oligotrophic environments is often limited by the availability of suitable organic electron donors. Chemolithoautotrophic bacteria may play a key role in denitrification in aquifers depleted in organic carbon. Under anoxic and circumneutral pH conditions, iron(II) was hypothesized to serve as an electron donor for microbially med...
Article
Nitrate reduction coupled to iron(II) oxidation (NRFO) has been recognized as an environmentally important microbial process in many freshwater ecosystems. However, well-characterized examples of autotrophic nitrate-reducing iron(II)-oxidizing bacteria are rare and their pathway of electron transfer as well as their interaction with flanking commun...
Article
Redox-driven biogeochemical element cycles play a central role in converting organic matter in aquatic ecosystems. They also perform key functions such as removing nitrate, mitigating the formation of greenhouse gases and weakening the effects of contaminants. Recent research has revealed the presence of redox-active compounds in these ecosystems w...
Article
Full-text available
The occurrence and activity of aerobic methanotrophs are influenced by environmental conditions, including pH, temperature, salinity, methane and oxygen concentrations, and nutrient availability. Aerobic methanotrophs synthesize a variety of lipids important for cell functions. However, culture-based experiments studying the influence of environmen...
Article
Laboratory studies on chemolithoautotrophic microbial denitrification coupled to pyrite oxidation at circumneutral pH yielded conflicting results. Some studies indicated that microbial oxidation of pyrite does occur, but several reports have shown that no microbial pyrite oxidation took place in experiments with pyrite as electron donor and nitrate...