Dirk Merten

Friedrich Schiller University Jena | FSU · Institute of Geosciences, Applied Geology

Streptomyces are important soil bacteria used for bioremediation of metal-contaminated soils, however, it is still unknown how metal-selective Streptomyces are and which mechanisms are involved during their capture. In this work, we exposed S. coelicolor spores to environmentally relevant concentrations (0.1, 1, 10, 100 μM) of Ce, U and Cd in solid...

Streptomyces can be used for bioremediation of heavy metal (HM) contaminated soil environments, however, the uptake mechanism is rather unexplored. Until recently, methods such as Transmission Electron Microscopy with Energy Dispersive X-ray spectroscopy (TEM-EDX) or total elemental analysis by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)...

Single particle (sp)ICP-MS is a powerful tool to characterise nanoparticles and colloids in aqueous suspensions with respect to their size, concentration and elemental composition. However, analysing suspensions containing water reactive particles is still challenging. For instance, Calcium-Silicate-Hydrates (C-S-H) develop during the early stages...

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...

The fungus Aspergillus oryzae could be shown to be a viable alternative for biosorption of valuable metals from solution. Fungal biomass can be obtained easily in high quantities as a waste of biofermentation processes, and used in a complex, multi-phase solution mimicking naturally occurring, mining-affected water samples. With test solution formu...

Elevated levels of particulate matter (PM) in urban atmospheres are one of the major environmental challenges of the Anthropocene. To effectively lower those levels, identification and quantification of sources of PM is required. Biomonitoring methods are helpful tools to tackle this problem but have not been fully established yet. An example is th...

The seaward litoral of the Island of Usedom, German and Polish coast of the Baltic Sea, was investigated by magnetic susceptibility and binocular/microscope for anthropogenic metal fragments, selected heavy minerals, and inorganic geochemistry to gain information on coastal dynamics. By multiparameter statistics a tool for the interpretation of the...

Atmospheric particulate matter has become a major issue in urban areas from both a health and an environmental perspective. In this context, biomonitoring methods are a potential complement to classical monitoring methods like impactor samplers, being spatially limited due to higher costs. Monitoring using spider webs is compared with the more comm...

Belowground ecosystems are accessible by mining, where a specific microbial community can be discovered. The biodiversity of a former alum mine rich in carbon, but with a low pH of 2.6-3.7 was evaluated by DNA- and cultivation-dependent methods using samples of the black slate rock material, secondary mineralization phases and seepage water. Pyrite...

Schizophyllum commune is a filamentous basidiomycete which can degrade complex organic macromolecules like lignin by the secretion of a large repertoire of enzymes. One of these white rot enzymes, laccase, exhibits a broad substrate specificity and is able to oxidize a variety of substances including carbonaceous rocks. To investigate the role of l...

Rare earth element (REE, La–Lu) patterns in groundwater are the result of complex solid–water interactions and can therefore be applied as process indicators in this system. At a remediated basement area of a heap in a post–U–mining area (Ronneburg, Germany), REE patterns in near surface groundwater were studied for 10 years (2005–2014) along a gro...

Microbiome analyses of soils and microcosm experiments depend on conditions that include sterilization in order to perform experimental manipulation of microbial communities. Still, they should represent conditions close to nature. When using metal contaminated soils, sterilization methods might alter metal availability. Here, four typical metal co...

Phytoremediation is a potential tool to clean up metal-polluted environments caused by technogenic activities such as mining. Large areas in the near of Ronneburg (eastern Thuringia, Germany) are highly heavy metal contaminated, caused by extensive uranium exploitation from 1949 to 1990. In our study, test sites at field scale were set up to grow h...

Substrates used for microbiological experiments like soil microcosms or microbiome analyses need to be homogenous and comparable, but concomitantly represent natural conditions as closely as possible. A crucial step is the choice of sterilization method, especially with respect to metal bioavailabilities. We analyzed four metal containing substrate...

Salts and brines have very low rare earth element (REE, La-Lu) concentrations. Thus, there is less knowledge of possible transfer of REE patterns during salt dissolution in water-rock interaction. REE levels in both media are close to or rather below limit of detection of commonly used methods. By dissolving salt samples in water followed by REE pr...

The use of rare earth elements (REE) as process indicators in water-rock interactions can be hampered by the fact that samples with high concentrations of total dissolved solids require dilution before ICP-MS analysis, which can lower REE concentrations close to or below detection limits. A pre-concentration method originally developed for chloride...

Ectomycorrhiza (ECM) describes the mutualistic interaction between trees and fungi. It is known that ECM fungi may increase the tolerance of their host trees against high levels of bioaccessible metals in the soil. The interfaces for the ECM interaction are specialized organs called short roots. In our study short roots of birch (Betula pendula L.)...

Microbial communities in soil, groundwater, and rock of two sites in limestone were investigated to determine community parameters differentiating habitats in two lithostratigraphic untis. Lower Muschelkalk and Middle Muschelkalk associated soils, groundwater, and rock samples showed different, but overlapping microbial communities linked to carbon...

The potential release of radionuclides from rock into soils and groundwater is a long-time endangerment to the environment. The (im)mobilization of elements is not strictly an abiotic process; in fact microorganisms contribute to metal release, transport and (co)precipitation. Therefore, the effect of microorganisms on release and transport of elem...

We reconstructed the contamination history of an area influenced by 40 years of uranium mining and subsequent remediation actions using dendroanalysis (i.e., the determination of the elemental content of tree rings). The uranium content in the tree rings of four individual oak trees (Quercus sp.) was determined by laser ablation with inductively co...

Groundwater microbiology with respect to different host rocks offers new possibilities to describe and map the habitat harboring approximately half of Earths' biomass. The Thuringian Basin (Germany) contains formations of the Permian (Zechstein) and Triassic (Muschelkalk and Buntsandstein) with outcrops and deeper regions at the border and central...

Natural Mn oxides are largely biogenic in origin, formed via the microbial oxidation of Mn(II). These minerals are extremely efficient scavengers of heavy metals, yet to date microbial Mn oxide precipitation and subsequent heavy metal sorption have received little attention in mining-impacted environments, where heavy metal concentrations are eleva...

Reclaiming land that has been anthropogenically contaminated with multiple heavy metal elements, e.g., during mining operations, is a growing challenge worldwide. The use of phytoremediation has been discussed with varying success. Here, we show that a careful examination of options of microbial determination of plant performance is a key element i...

Extensive uranium mining in the former German Democratic Republic (GDR) in eastern Thuringia and Saxony took place during the period of 1946-1990. During mining activities, pelitic sediments rich in organic carbon and uranium were processed and exposed to oxygen. Subsequent pyrite oxidation and acidic leaching lead to partial contamination of the a...

In a profile with two cemented layers sampled in an area affected by acid mine drainage, both have rare earth element (REE) signatures with positive Ce anomalies in the Post Archean Australian Shale - normalised patterns. Both cemented layers have higher contents of environmentally relevant metals (Cd, Co, Cu, Fe, Mn, U, and Zn) than the over- and...

Heavy metal-contaminated soil derived from a former uranium mining site in Ronneburg, Germany, was used for sterile mesocosms inoculated with the extremely metal-resistant Streptomyces mirabilis P16B-1 or the sensitive control strain Streptomyces lividans TK24. The production and fate of bacterial hydroxamate siderophores in soil was analyzed, and...

Biological Mn oxidation is responsible for producing highly reactive and abundant Mn oxide phases in the environment that can mitigate metal contamination. However, little is known about Mn oxidation in low-pH environments, where metal contamination often is a problem as the result of mining activities. We isolated two Mn(II)-oxidizing bacteria (MO...

This study aims on identifying growth site and plant part specific element patterns in sunflower (Helianthus annuus). Sunflowers (H. annuus) were planted in small-scaled plots under field conditions on a metal-contaminated and a non-contaminated site over a vegetation period of 170 days. Nitric acid soluble contents of Ca, Cd, Co, Cr, Cu, Fe, K, Mg...

On an uranium-mining-influenced area, sunflowers (Helianthus annuus) were grown on a small-scaled plot. Subsamples of sunflowers were harvested 34, 66, 96, 108, 140, and 170 days after sowing. Contents of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Th, U, Zn, and rare earth elements (REEs, La–Lu) were determined in the sunflower shoots, as well as total and bi...

The commonly observed enrichment of middle rare earth elements (MREE) in water sampled in acid mine drainage (AMD)-impacted areas was found to be the result of preferential release from the widespread mineral pyrite (FeS2). Three different mining-impacted sites in Europe were sampled for water, and various pyrite samples were used in batch experime...

The impact of the extremely heavy metal resistant actinomycete Streptomyces mirabilis P16B-1 on heavy metal mobilization/stabilization, phytoremediation and stress level of plants was analyzed in the presence and absence of Sorghum bicolor in sterile microcosms containing highly metal contaminated or control soil. For control, a metal sensitive S....

The remediation of large heavy metal/radionuclide (HM/R) contaminated areas by conventional ex-situ techniques (excavation or chemical treatment/-stabilization) is expensive, and low cost strategies with a long-term stabilization effect of such sites are a task of next years research. Phytoremediation can be an alterative solution and sustainable t...

Phytoremediation is an environmental friendly, cost-effective technology for a soft restoration of abandoned mine sites. The grasses Agrostis capillaris, Deschampsia flexuosa and Festuca rubra, and the annual herb Helianthus annuus were combined with microbial consortia in pot experiments on multi-metal polluted substrates collected at a former ura...

Distribution and behavior of contaminants in plants are of increasing interest both for food production and phytoremediation. Elements like Cd, Cr, Cu, Mn, Ni, and Zn are in the focus of investigations, due to their nutritive function, but also potential toxicity for plants and human. Laser ablation–inductively coupled plasma–mass spectrometry (LA–...

The formation of soil organic matter (SOM) has been proposed to depend on fragmentation of biomass after cell death. However, this is hard to mimic in laboratory experiments showing the process directly. We used heavy metal contamination in order to provide an environment in which one Streptomyces strain, the heavy metal resistant S. mirabilis P16B...

Biomineralization by heavy metal-resistant streptomycetes was tested to evaluate the potential influence on metal mobilities in soil. Thus, we designed an experiment adopting conditions from classical laboratory methods to natural conditions prevailing in metal-rich soils with media spiked with heavy metals, soil agar, and nutrient-enriched or unam...

On a test field situated at a former uranium mining site near Ronneburg (Thuringia, Germany) a small scale time - series field experiment with sunflowers (Helianthus annuus) was carried out. This area has elevated contents for the heavy metals Cd, Co, Cr, Cu, Ni, Zn including the radionuclides U and Th. Over a time period of 24 weeks the sunflowers...

The remediation of large heavy metal/radionuclide (HM/R) contaminated areas by conventional remediation technologies is often too expensive. Phytoremediation can be an alternative for such areas with slight contaminations, and represents a convenient and sustainable method of remediation. Field site phytoremediation experiments were carried out at...

Seven geothermal springs from the Precambrian high-grade metamorphic terrain of Sri Lanka were investigated to assess their formation processes and to determine reservoir temperatures based on their chemical compositions. Silica-based geothermometric calculations for the Marangala and Nelumwewa springs showed the highest average reservoir temperatu...

Hydrochemical modeling, graphical methods, and different statistical techniques were applied to under-stand the nature of geological and hydrochemical processes in a shallow groundwater aquifer of the Jena biodiversity experimental field. Factor and cluster analyses were used to identify the governing underlying processes and to detect the spatial...

Geomicrobial cycles influence metal mobilities in soil. The formation of Fe and Mn(hydr)oxides in biogeochemical horizons and the subsequent mobilization of Mn from the substrate can lead to high mobility of Mn. This process of Mn mobilization was studied in substrates derived from a former uranium mining area in column experiments. Microbially inf...

Heavy metal contamination of soil has an immense impact on the surrounding environment, such as the ground water, and hence, has become an important issue within bioremediation. Therefore, heavy metal contamination has to be determined preferably cost‐efficiently, rapidly, and reliably. Here, soil bacteria of the genus Streptomyces are used as bioi...

The Thuringian basin is the major geological structural unit in the federal state of Thuringia, Germany. It consists of sandstones, limestones, clays, gypsum and salts, that were deposited from the Upper Permian until the Lower Jurassic (approximately 250 to 180 million years ago). The largest deposits are Buntsandstein, Muschelkalk and Keuper, all...

Heavy metal contamination of large areas due to uranium mining operations poses a serious long-term environmental problem. In the Ronneburg district (eastern Thuringia, Germany), leaching of low grade uranium bearing ores (uranium content < 300 g/t) occurred from 1972 to 1990 using acid mine drainage (AMD; pH 2.7-2.8) and diluted sulphuric acid (10...

Uranium mining near Ronneburg, Germany resulted in widespread environmental contamination with acid mine drainage (AMD) and high concentrations of heavy metals and radionuclides. Despite physical remediation of the area, groundwater is still a source of heavy metal contaminants, e.g., Cd, Ni, Co, Cu and Zn, to nearby ecosystems. However, natural at...

The cosmopolitan perennials, giant goldenrod and stinging nettle reach with 6.2–11.3 t ha–1 (DW) the biomass production of those annual crops which are recommended for heavy metal extractions from soils but share with those the intolerable cleanup times. Due to their economic and environmental advantages, cropping rod and nettle, e.g., as renewable...

Phytoremediation is applied to a site in the former uranium mining area of Ronneburg in Eastern Thuringia, Germany, slightly contaminated with heavy metals and radionuclides (HM/R). In a joint research project, remediation of HM/R-contaminated sites is investigated and concepts for the subsequent utilization of the contaminated plant residues are d...

Rare earth elements (REE) are heavy metals with increasing technical application and importance in science. They are found in minerals like monazite and bastnaesite, which contain especially La and Ce. In waters, REE abundance strongly depends on pH, with acid mine drainage influence resulting in higher REE concentrations. The range of REE in solid...

Stable isotopes, 2Hwater, 18Owater as well as 18Osulphate and 34Ssulphate, were used to study the flow system of shallow groundwater and soil water at the base area of a former leaching heap at the uranium mining area of Ronneburg, Germany. The flow paths and water-retention times were estimated by comparison of δ2H and δ18O values in groundwater a...

The Rotliegend saline lake periodically covered wide areas of the Southern Permian Basin in Northwest Europe during the Permian. The sedimentology, mineralogy and geochemistry of lake deposits were studied to document very high frequency lake level fluctuations and to evaluate their triggers. Increased precipitation and marine ingressions into the...

Gerth, A., Merten, D., Baumbach, H.: Distribution, community context, and genetic population structure of Alyssum montanum L. on metalliferous soils in the eastern foreland of the Harz Mountains.-Hercynia N. F. 44 (2011): 73-92. The distribution pattern and the community context of Alyssum montanum L. (Brassicaceae) on copper shale spoil heaps in t...

Methods permitting to test the influence of the matrix as well as of its local and temporal distribution on the plasma conditions in laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) are developed. For this purpose, the MS interface is used as plasma probe allowing to investigate the average plasma condition within the ICP zon...

Much progress has been achieved over the past 20 years in remediating sites contaminated by heavy metal. However, very large contaminated areas have presented major problems to this day because of remediation costs. Phytoremediation is a new, emerging, sustainable technique of remediating areas with low heavy-metal contamination. One advantage of p...

The hydrogeochemistry of rare earth elements (REE) in the former uranium mining area of Ronneburg/germany was studied with emphasis on processes leading to their fractionation. In the acidic groundwater, REE concentrations of up to 8.15 mg/L were measured. normalisation resulted in site-specific characteristics: Enrichment of middle (and heavy) REE...

Groundwater samples have been collected in years 2006 to 2009 from eighteen shallow groundwater wells of Jena biodiversity experiment area for hydrochemical investigations and then for studying how it affects aboveground plant diversity. In this study only the hydrochemical characterization is considered. Hydrochemical modeling using PHREEQC 2 (Par...

Contamination of large areas by industrial or mining activities is a serious environmental problem. Selection pressure in these polluted habitats led to adaptation in microorganisms now containing special resistance mechanisms as a result to the permanent exposure to exceedingly high concentrations of heavy metals. Banks of a creek in a former uran...

As a toxic metal, cadmium (Cd) affects microbial and plant metabolic processes, thereby potentially reducing the efficiency of microbe or plant-mediated remediation of Cd-polluted soil. The role of siderophores produced by Streptomyces tendae F4 in the uptake of Cd by bacteria and plant was investigated to gain insight into the influence of siderop...

Large sites with a low contamination of metall(oid)s were in the past a problem for remediation measures - the "traditional" processes were too expensive for an application on such expanded areas. Phytoremediation can be an alternative for such low contamination problems. In Germany, a research project is performed on this subject, in cooperation o...

Lysimeter experiments were performed in order to investigate the effects of two bioremediation methods on the export of metals from a former uranium mine site located near Ronneburg, Thuringia, Germany. The first method consisted of the application of topsoil and compost to contaminated soil. Soil was sampled from two amended plots and from an unam...

Microbially assisted dissolution of biotite was studied using four environmentally important species (Bacillus subtilis, Shewanella putrefaciens, Streptomyces acisdiscabies, and Schizophyllum commune) incubated for 35 days in batch reactors at slightly alkaline pH conditions (ca. pH 9.5). For comparison we performed a control experiment without bio...

The test site Gessenwiese is located at the base area of the former uranium-leaching heap Gessenhalde near Ronneburg, Thuringia, Germany. Leaching operations were performed at the heap between 1971 and 1989, when waste rocks with a low grade of uranium mineralisation (uranium content <300 g/t) were leached with acid mine drainage until 1978 and sub...

Understanding the co-precipitation and sorption of metals and radionuclides in minerals and the biologically induced release of metals is important for predicting the future contaminant mobility in sediments affected by groundwater flow. This study aims to determine the retention of heavy metals in local epigenetic zones, termed geochemical barrier...

Contamination of large areas by industrial or mining activities is a serious environmental problem. Selection pressure in these polluted habitats led to adaptation in microorganisms now containing special resistance mechanisms as a result to the permanent exposure to exceedingly high concentrations of heavy metals. Banks of a creek in a former uran...

High levels of metals impede plant growth by affecting physiological processes. Siderophores are microbial Fe-chelators that, however, bind other metals. This study evaluated plant growth in a soil containing elevated levels of metals, including Al, Cu, Fe, Mn, Ni, and U, using Streptomyces-derived cell-free supernatant containing siderophores and...

The siderophore-producing ability of nickel-resistant Streptomyces acidiscabies E13 and the role of the elicited siderophores in promoting plant growth under iron and nickel stress are described. Siderophore assays indicated that S. acidiscabies E13 can produce siderophores. Electrospray ionization mass spectrometry (ESI-MS) revealed that the bacte...

The concentration of metals in microbial habitats influenced by mining operations can reach enormous values. Worldwide, much emphasis is placed on the research of resistance and biosorptive capacities of microorganisms suitable for bioremediation purposes. Using a collection of isolates from a former uranium mining area in Eastern Thuringia, German...

Column experiments were carried out using contaminated geosubstrates and previously isolated Streptomyces strains from the former uranium mining area Ronneburg (Germany) to study transfer processes of heavy metals including radionuclides. Preliminary tests with comparatively low heavy metal and radionuclide contaminated surface material showed stro...

Tremendous values of up to 8 mg/L total REE (Rare Earth Elements) are observed in ground water affected by Acid Mine Drainage (AMD) in a former uranium mining area of Eastern Thuringia, Germany. The distribution of REE is applied to study processes in (bio)remediation of AMD. Normalization of REE concentrations in water to Post Archean Australian S...

The use of microorganisms for the extraction of contaminants like solved metals from drainage or surface waters was investigated using strains adapted to a polluted environment at a former uranium mining site near Kauern, Eastern Thuringia, Germany. Soil respiration data showed increasing variation indicating stress response and hence need for adap...

Ausschließlichpara: Mit der Nitrogruppen bildenden N-Oxygenase AurF, eingesetzt in vivo, in vitro und als immobilisiertes Fusionsprotein, sowie einfach mit H2O2 als Oxidationsmittel gelingt die para-regioselektive Oxygenierung aromatischer Amine (siehe Schema). Diese charakteristische Reaktivität ermöglicht auch die selektive Oxygenierung von Diami...

Action by the para: Evaluation of the nitro-group-forming N-oxygenase AurF in vivo, in vitro, and immobilized as a fusion protein with simply H2O2 as oxidant (peroxide shunt) reveals para-regioselective oxygenation of aromatic amines (see scheme). This effect includes the selective oxygenation of diamino compounds.

Summary The influence of calcite, dolomite, pyrite and vaterite on the kinetics of uranium release from a natural rock under relevant, i.e., field conditions has been investigated. The time dependence of the U release has been studied in two different experimental procedures (open and closed systems) at laboratory temperature (21±2 °C). Performing...

A solubilization study for in total 782 days using not shaken batch experiments with uranium-bearing rock and three natural carbonate minerals was conducted to characterize uranium (U) leaching under oxic conditions. Results showed that aqueous U concentration increased continuously with a solubilization rate of 0.16 ▭gm-2h-1 for the first 564 d (1...

The influence of calcite, dolomite, pyrite and vaterite on the kinetics of uranium release from a natural rock under relevant, i.e., field conditions has been investigated. The time dependence of the U release has been studied in two different experimental procedures (open and closed systems) at laboratory temperature (21±2 °C). Performing batch ex...

Signal equations basing on dispersion functions describing the measured temporal intensity distribution for laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) used in scanning and drilling mode are developed. Variable ablation rates due to either varying focussing conditions typical for drilling mode and due to the changes of p...