API src

Found 16892 results.

Similar terms

s/asa/As/gi

Other language confidence: 0.5819191618622189

Absolute abundances of methane- and sulfate-cycling microorganisms, pore water gas concentrations and stable carbon isotopes (Table 1)

Soil cores for microbial, dissolved gas concentrations and isotopic analysis were taken using a Russian type peat corer (De Vleeschouwer et al. 2010) before and after rewetting. Each time, we took duplicates at stations 1-8 for this rather labor-intensive process and divided the core into four depth sections: surface, 5–20, 20–40 and 40–50 cm. Subsamples for dissolved gases and stable carbon isotope analyses were taken with tip-cut syringes with a distinct volume of 3 ml (Omnifix, Braun, Bad Arolsen, Germany) and immediately placed into NaCl-saturated vials (20 ml, Agilent Technologies, 5182-0837, Santa Clara, USA) leaving no headspace and closed gas-tight using rubber stoppers and metal crimpers (both: diameter 20 mm, Glasgerätebau Ochs, Bovenden, Germany).

Water and sediment analysis from column experiments

This data set contains data from water analyses from column experiments. The water analyses included cations (sodium, potassium, calcium, magnesium, iron and manganese), anions (nitrate, chloride, sulphate, bromide and phosphate) and selected trace elements (arsenic, cobalt, nickel, vanadium and zinc). The column experiments were conducted with two different types of unconsolidated sandy sediments from aquifers in Denmark (Quaternary) and Germany (Cretaceous). In both sediments, the nitrate degradation capacity was almost exhausted. To induce denitrification, 5 mmol ethanol was added to the column experiments. This also caused a decrease in the concentration of trace elements in the water. A sequential extraction procedure was performed to determine the trace element sinks. The data set therefore also contains contents of selected elements (equal to water analyses) from the sequential extraction procedure of the sediment before and after the column tests. The results observed in the laboratory were additionally modeled with Phreeqc. The Phreeqc input data complete the data set.

Grundwassermessstelle DEGM_39390015: Hagendorf

Stammdaten und Analysedaten zu den Grundwassermessstellen im EUA-Messnetz: Messtelle DEGM_39390015 (Hagendorf)

Grundwassermessstelle DEGM_DENW_059140331: Hünenpforte

Stammdaten und Analysedaten zu den Grundwassermessstellen im EUA-Messnetz: Messtelle DEGM_DENW_059140331 (Hünenpforte)

Messstelle 2195 Lonsheim (Messstellen-Nr: 2549105000)

Die Messstelle 2195 Lonsheim in Rheinland-Pfalz dient der Überwachung von Grundwasserstände. Zeitreihen abiotische Parameter werden derzeit nicht gemessen.

Nachhaltige Ansätze zur Minimierung von Arsen in Trinkwasser und Reis in Vietnam

Arsen-kontaminiertes Grundwasser stellt eine große Gefahr für zig Millionen von Menschen dar, insbesondere in Süd- und Südost-Asien, durch seine Verwendung als Trinkwasser und für die Bewässerung von Reisfeldern. Das Hauptziel dieses Projekts ist es gemeinsam mit Wissenschaftlern der Stanford University die Menge an giftigem Arsen in den beiden wichtigsten Expositionsquellen, Wasser und Reis, zu reduzieren und zu bestimmen wie i) Arsen effizient mit Wasserfiltern aus dem Trinkwasser entfernt und ii) die Arsenaufnahme durch Reis während der Nasskultivierung reduziert werden kann. Im ersten Teilprojekt planen wir in Vietnam zu untersuchen, unter welchen Bedingungen Wasserfilter Arsen effizient entfernen, wie lange die Filter verwendet werden können und ob gesundheits-schädigende Konzentrationen von Nitrate in den Filtern gebildet werden. Wir werden einen visuell sichtbaren Indikator in den Filtern entwickeln, der es der breiten Bevölkerung erlaubt, ohne analytische Verfahren oder besonderen Bildungsstand zu bestimmen, wann die Effizienz des Filters aufgrund der Sättigung mit Arsen verschwindet und das Filtermaterial ersetzt werden muss. Darüber hinaus werden wir untersuchen, wie das Arsen-verschmutzte Filtermaterial ohne weitere Risiken entsorgt werden kann. Im zweiten Teilprojekt werden wir untersuchen, ob die Stimulation von nitrat-reduzierenden, eisenoxidierenden Bakterien in Reisfeldböden die Arsenaufnahme in Reis reduziert durch die Bindung von Arsen an die gebildeten Minerale. Wir werden bestimmen, wie die Zugabe definierter Mengen an Nitrat helfen kann, gleichzeitig die Arsenaufnahme in den Reis und die Emission des Treibhausgases N2O zu minimieren. Dieses Projekt wird für die Bevölkerung in Arsen-betroffenen Ländern praktische Lösungen bieten, um mögliche Schädigungen durch Arsen und Nitrat zu reduzieren und ihre Gesundheit und Lebenssituation zu verbessern.

Grundwassermessstelle APP_GWMN_563

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_563 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EL13 : Krückau - Altmoränengeest Nord. Es liegen insgesamt 24368 Messwerte vor. Es liegen außerdem 15 Probenentnahmen vor (siehe Resourcen).

Pan-Arctic Visualization of Landscape Change (2003-2022), Arctic PASSION Permafrost Service

This raster dataset, in Cloud Optimized GeoTIFF format (COG), provides information on land surface changes at the pan-arctic scale. Multispectral Landsat-5 TM, Landsat-7 ETM+, and Landsat-8 OLI imagery (cloud-cover less than 80%, months July and August) was used for detecting disturbance trends (associated with abrupt permafrost degradation) between 2003 and 2022. For each satellite image we calculated the Tasseled Cap multi-spectral index to translate the spectral reflectance signal to the semantic information Brightness, Greenness, and Wetness. In order to characterize change information, we calculated the linear trend of the Brightness, Greenness and Wetness over two decades on the individual pixel level. The final map product therefore contains information on the direction and magnitude of change for all three Tasseled Cap parameters in 30m spatial resolution across the pan-arctic permafrost domain. Features detected include coastal erosion, lake drainage, infrastructure expansion, and fires. The general processing methodology was developed by Fraser et al. 2014 and adapted and expanded by Nitze et al. 2016 and Nitze et al. 2018. Here we upscaled the processing to the circum-arctic permafrost region and the recent 20-year period from 2003 through 2022. The service covers the permafrost region up to 81° North: Alaska (USA), Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia, Mongolia, and China. For Russia and China, regions not containing permafrost were excluded. The data has been processed in Google EarthEngine within the research projects ERC PETA-CARB, ESA CCI+ Permafrost, NSF Permafrost Discovery Gateway, and EU Arctic PASSION. The dataset is a contribution to the 'Panarctic requirements-driven Permafrost Service' of the Arctic PASSION project (see references). Changes in the Tasseled Cap indices Brightness, Greenness, and Wetness are displayed in the image bands red, green, and blue, respectively. Here, coastal erosion (a trend of a land surface transitioning to a water surface) is depicted in dark blue colors, while coastal accretion (a trend of a water surface transitioning to a land surface) is depicted in bright orange colors. Drained lakes appear in bright yellow or orange colors, depending on the soil conditions and vegetation regrowth. Fire scars are a further common feature, which can appear in different colors, depending on the time of the fire and pre-fire land cover. The data can be explored via the Arctic Landscape EXplorer (ALEX, see references) and is available as a public web map service (WMS, see references), both hosted by Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research.

Brackish water rewetting of a temperate coastal peatland in NE Germany: Effects on Biogeochemistry, Microorganisms and Greenhouse gas emissions

The rewetting of drained peatlands is a promising measure to mitigate carbon dioxide (CO2) emissions by preventing the further mineralization of the peat soil through aeration. While freshwater rewetted peatlands can be significant methane (CH4) sources in the short-term, in coastal ecosystems the input of sulfate-rich seawater could potentially mitigate these emissions. The purpose of the data collection was to examine whether the presence of sulfate, known as an alternative electron acceptor, can cause lower CH4 production and thus, emissions by favoring the growth of sulfate-reducers, which outcompete methanogens for substrate. We therefore investigated underlying variables such as the methane-cycling microbial community along with CH4 fluxes and set them in context with CO2 fluxes along a transect in a coastal peatland before and directly after rewetting. In this way, a conclusion about the short-term greenhouse gas mitigation potential of brackish water rewetting of coastal peatlands could be drawn. This data collection consists of six data sets, with direct comparisons before and after rewetting of CO2 and CH4 fluxes (Tab. 2) and associated microbial communities (Tab. 1) being the main data. Pore water geochemistry (Tab. 1 and 3) and surface water parameters (Tab. 4) were collected simultaneously to provide potential explanatory variables. The sampling of continuous water level (Tab. 5) within wells and atmospheric weather data (air and soil temperature, relative humidity, photosynthetic photon flux density; Tab. 6) from a weather station was done in addition. Measurements started in June/July/August 2019 after field installation was finalized and were conducted on the drained coastal fen "Polder Drammendorf" on the island of Rügen in North-East Germany. On 26th November 2019, the dike was opened and channeled in order to rewet the peatland with brackish water. Before, the dike separated the peatland from the adjacent bay "Kubitzer Bodden", which is part of a brackish lagoon system connected to the Baltic Sea. Therefore, the peatland was nearly completely flooded and now resembles a shallow lagoon with high fluctuating water levels. We measured along a humidity (pre-rewetting)/water level (post-rewetting) gradient (stations 0-8) towards and across the main North-South oriented drainage ditch, including four stations on the Eastern side of the ditch (1–4), two ditch stations (0, 5) and two stations (6, 7) on the Western side of the ditch. Station 8 was chosen as an additional station farther towards the adjacent bay on the Western side, but was only accessible before rewetting. CH4 and CO2 fluxes (stations 0-7) were calculated from online gas concentrations measurements using laser-based analyzers and manual closed chambers (Livingston, G. P., & Hutchinson, G. (1995). Enclosure-based measurement of trace gas exchange: Applications and sources of error. In P.A. Matson, & R.C. Harriss (Eds.). Biogenic trace gases: Measuring emissions from soil and water (pp. 14–51). Blackwell Science Ltd., Oxford, UK). Soil cores for microbial, dissolved gas concentrations and isotopic analysis were taken using a Russian type peat corer (De Vleeschouwer, F., Chambers, F. M., & Swindles, G. T. (2010). Coring and sub-sampling of peatlands for palaeoenvironmental research. Mires and Peat, 7, 1–10) before and after rewetting. Each time, we took duplicates at stations 1-8 for this rather labor-intensive process and divided the core into four depth sections: surface, 5–20, 20–40 and 40–50 cm. Subsamples for dissolved gases and stable carbon isotope analyses were taken with tip-cut syringes with a distinct volume of 3 ml (Omnifix, Braun, Bad Arolsen, Germany) and immediately placed into NaCl-saturated vials (20 ml, Agilent Technologies, 5182-0837, Santa Clara, USA) leaving no headspace and closed gas-tight using rubber stoppers and metal crimpers (both: diameter 20 mm, Glasgerätebau Ochs, Bovenden, Germany). Absolute abundances of specific functional target genes, including methane- and sulfate-cycling microorganisms, were measured with quantitative PCR (qPCR) after DNA was extracted (GeneMATRIX Soil DNA Purification Kit, Roboklon, Berlin, Germany) and quantified (Qubit 2.0 Fluorometer, ThermoFisher Scientific, Darmstadt, Germany). Surface and pore water parameters were measured in parallel to the gas measurements and soil coring for microbial analyses. Most surface water variables (pH, specific conductivity, salinity, nutrients, oxygen, sulfate and chloride concentrations, DOC/DIC) were measured in-situ using a multiparameter digital water quality meter or taken to the laboratory as water samples for further analysis. Likewise, pore water/soil variables (pH, specific conductivity, nutrients, metals, sulfate and chloride concentrations, CNS) were either measured in-situ or taken to the laboratory as soil samples. While surface water analysis was only conducted in the drainage ditch before rewetting, it was done along the entire transect after rewetting. In contrast, pore water/soil analysis was mostly conducted before rewetting and only repeated occasionally after rewetting where possible.

Salinity, temperature, pH, and fluorescent dissolved organic matter (fDOM) measurements in surface waters within DynaCom experimental islands and saltmarsh enclosed plots at different elevation levels, Spiekeroog, Germany, 2018-08 to 2022-01

Data were collected between August 2018 and January 2022 as part of the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems) of the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Measurements were conducted almost bi-/monthly on experimental islands and salt marsh enclosed plots located in the back barrier tidal flat and salt marsh of the island of Spiekeroog (Germany). Field-based in situ measurements of salinity, temperature, and pH were conducted using portable hand-held instruments in groundwater (filter tubes within experimental plots) and in surface waters from a tidal channel (ITC) adjacent to the experimental islands and a tidal pond (STP) in the pioneer zone of the salt marsh. Measurements were performed and samples were taken during the day between 3 hours before and 3 hours after low tide. From August 2018 to September 2019 a HQ40D digital two-channel multi meter equipped with a pre-calibrated Intellical CDC401 field 4-pole graphite conductivity cell (Hach Lange GmbH, Germany) was used to measure temperature (°C) and salinity (psu). The same device was used for pH measurements with an Intellical PHC101 field low maintenance gel filled pH electrode (Hach Lange GmbH, Germany). The pH electrode was calibrated before each fieldwork using single-use pH buffer solutions (pH 4.01, 7.00, 10.01, Hach Lange GmbH, Germany). Since October 2019, salinity and temperature were measured using a Multi 3510 IDS SET 4 handheld device equipped with a TetraCon® 925/LV 4-Pol-IDS conductivity electrode with graphite cells (WTW, Xylem Analytics Germany GmbH, Germany). Fluorescent dissolved organic matter (FDOM, ppb QSE) was measured using an AquaFluor Modell 80000-010 for UV-420 (Turner Designs Inc., USA), pre-calibrated in the laboratory. For this, water samples were taken from the field to a nearby mobile central field unit and were filtered within 1-2 hours after sampling using 25 mm Nuclepore syringe filters (0.2 µm pore size) directly into sample-pre-rinsed measurement cuvettes. Data quality control (QC) was performed using MATLAB (R2024b). Outlier detection was conducted both visually and statistically using z-score analysis (|z| > 3) per sampling campaign and plot. Each data point was assigned a Quality Control Flag (QC).

1 2 3 4 5 … 1688 1689 1690