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The adsorption of boron on detrital particles like clay or metal oxides is thought to be a major mechanism driving changes in the boron isotopic composition of seawater on geologic timescales. However, the sensitivity of adsorption parameters to long-term changes in the seawater concentration of major ions (Mg2+, Ca2+, SO42-) and dissolved inorganic carbon (HCO3-, CO32-) is not known. We conducted multiple sets of adsorption experiments that consist of suspending pretreated clay minerals (either kaolinite, smectite or illite) in artificial seawater with a modified chemical composition. Specifically, we investigate adsorption in seawater with a major ion composition resembling that of the Cretaceous (100 Ma) and the Eocene (50 Ma), as well as modern seawater with either reduced or elevated concentrations of dissolved inorganic carbon. We finally combine the results with modeled values for the mineral assemblage of detrital sediment to constrain boron adsorption fluxes in the past. The dataset consists of two sheets that store (1) the results of our adsorption experiments and (2) the modeled sediment properties. Experiments were performed on KGa-1b kaolinite, SWy-3 smectite and IMt-2 illite obtained from the Clay Mineral Society. For each of these clays, a consistent particle size fraction of 2 – 0.2 μm was extracted by repeated centrifugation and decantation. As a result, clay samples used in the experiments have a high mineralogical purity of 95% (in the case of kaolinite and illite) and 50% (in the case of smectite). Pretreated clays were submerged in one of four different boron-containing artificial seawater solutions. These seawater solutions were prepared by mixing trace element-grade salts with ultrapure water according to the recipe of Millero (2013). Specifically, the amounts of added MgCl2, CaCl2, Na2SO4 and NaHCO3 were varied to produce four different seawater stock solutions that have (i) a major ion concentration similar to Eocene seawater; (ii) a major ion concentration similar to Cretaceous seawater; (iii) a DIC concentration half as high as in modern seawater; (iv) a DIC concentration twice as high as in modern seawater. Clay and seawater were allowed to interact for 48h through continuous agitation, after which solution samples were extracted.
This dataset contains element concentrations of six different hydrological compartments sampled on a daily basis over the course of one year in two neighboured first order headwater catchments located in the Conventwald (Black Forest, Germany). Critical Zone water compartments include above-canopy precipitation (bulk precipitation including rainwater, snow and fog water), below-canopy precipitation (throughfall), subsurface flow from three distinct soil layers (organic layer, upper mineral soil, deep mineral soil), groundwater, creek water and spring water. Element concentrations include major elements (Ca, K, Mg, Na, Si, S), trace elements (Al, Ba, Cr, Cu, Fe, Li, Mn, P, Sr, Zn), anion (Cl), and dissolved organic elements (DOC, DON). The data were used to explore concentration (C) - discharge (Q) relationships and to calculate short-term element-specific chemical weathering fluxes, which were compared with previously published long-term element-specific chemical weathering fluxes. The ratio of both weathering fluxes, described by the so-called “Dissolved Export Efficiency” (DEE) metric revealed deficits in the stream dissolved load. These deficits were attributed to colloid-bound export and either storage in re-growing forest biomass or export in biogenic particulate form. Tables supplementary to the article, including data quality control, are provided in .pdf and .xlsx formats. In addition, data measured in the course of the study are also provided as machine readable ASCII files.
The need for the software is based on being able to make a statement as to whether the operation of a Pumped Hydropower Storage (PHS) facility in a former open-pit lignite mine can have a negative impact on the water quality in the lower reservoir and associated aquifers. The research question arises since flooded lignite mines are often associated with acidification and/or increased sulphate and metal concentrations. Thus, the software aims at modelling geochemical processes during the PHS operation in open-pit lignite mines. The reaction path modelling framework comprises a Python framework for data management and a solver for geochemical reactions (phreeqc/phreeqpy; Parkhurst and Appelo, 2013; Müller, 2011). The software is based on a conceptual geochemical model that includes the main geochemical processes that are expected to influence the hydrochemistry. It integrates different non-dimensional batch reactors, each representing the water composition of the reservoirs, and water sources or sinks in the PHS system (groundwater, rainwater, surface run-off, mine dump water). These waters are cyclically mixed with ratios deducted from flow rates and time-dependent influxes of a hypothetical PHS system. The water influxes have different chemical compositions based on the geochemical scenarios defined with the input data. An instant flooding of the mine with scenario-specific mixing ratios of rainwater, groundwater and mine dump water is simulated to provide an initial solution in the LR for the PHS operation. For the simulation of the PHS operation, the water volume of the UR is extracted from the LR and equilibrated with atmospheric partial pressures of oxygen and carbon dioxide to represent the water composition after pumping. The water composition evolving at the reservoir-mine dump interface layer is simulated by a kinetically controlled reaction of pyrite (Williamson and Rimstid, 1994) and calcite (Plummer, 1978) with the LR water. During the PHS discharge cycle, water flows into the adjacent mine dump sediments due to the increasing hydraulic head gradient in the LR compared to the surrounding groundwater aquifers. Water from the LR is mixed with rainwater, groundwater, surface run-off, and water from the reservoir-mine dump interface layer according to the water volumes that enter the reservoir during the respective cycle. Finally, the new water composition in the LR is mixed with the water from the UR to simulate the PHS discharge into the LR. Apart from gas exchange, evaporation and precipitation, no reactions are simulated for the water in the UR, as the reservoir is assumed to be artificially sealed. Pump and discharge cycles are simulated until the pH and sulfate concentrations in the LR do not change by more than 1 x 10-4 and 1 x 10-5 mol kgw-1 within two consecutive PHS cycles, respectively. Otherwise, the simulation is terminated after 7,300 PHS cycles, representing 20 years of operation with a duration of one day per cycle. Input parameter ranges can cover a wide range of potential hydrogeochemical scenarios. In the software provided with this manual, a small range of generic data is defined as input to limit the simulation time and data output. However, the input can be modified to simulate a broader range of geochemical scenarios as described in the associated data description file.
Adsorption and isotopic fractionation of boron on clastic sediment is one process responsible for the heavy boron isotopic composition of the modern ocean. However, the mechanism by which boron complexes to the surface of clay minerals and the cause of its isotopic fractionation are still unclear. We performed two sets of experiments, using solutions of pure water with added boron and seawater, to explore the isotope behavior during adsorption of boron onto kaolinite, smectite and illite. The dataset consists of an excel file with four sheets that store (1) the NIST RM 803 measurements we used to establish the long-term reproducibility of our isotope measurements, (2) results of our pure experiment, (3) results of our seawater experiments and (4) a global compilation of XRD-based riverine clay mineral assemblages.
The dataset presented here encompasses the results of the geochemical analyses of water and recent carbonate samples collected in the El Peinado basin located in the Southern Puna Plateau in Catamarca, Argentina. This system formed by the hypersaline lake Laguna del Peinado, numerous hydrothermal springs, and the small hypersaline lake Laguna Turquesa, provides a natural laboratory to study carbonate formation and the mechanisms that control the incorporation of various elements and isotopes into their structure under a broad range of geochemical conditions. Geochemical analyses include data on the physicochemical parameters, elemental, and isotopic (δ18O, δ2H, δ11B) composition of the waters, and data on the elemental and isotopic (δ18O, δ13C, δ11B) composition of the carbonates. These data allowed us to calculate element partition coefficients and isotopic fractionation between coupled water-carbonate samples from this natural setting, which are also included here. This dataset also includes the results of water modelling using the software PHREEQC, which contains data on the chemical speciation of carbon and boron, the species contributing to total alkalinity, and mineral saturation indices. This information is useful for all those dealing with geochemistry of hypersaline lakes, geochemistry of continental carbonates, as well as paleoenvironmental and paleoclimatic studies using lake carbonates as archives. These data correspond to the research article “On the origin and processes controlling the elemental and isotopic composition of carbonates in hypersaline Andean lakes”. The full description of the data is provided in the data description file.
The main component of this data publication is a dataset of predicted daily nutrient concentrations for NO3-N and TP for 150 monitoring stations along 60 German rivers (main rivers). The aim of this dataset is to fill the data gap of daily nutrient concentrations for a better understanding of nutrient transport from the rivers to the seas. So far, nutrient concentrations are sampled on a fortnightly basis, which can be insufficient for nutrient retention models working on a daily basis. With this method and available datasets, river basin managers have the opportunity to look at nutrient concentrations or load patterns on a finer resolution to adapt their management to improve water quality. The dataset was obtained by a random forest model (RF) based on measured NO3-N and TP concentrations between the years 2000 and 2019. The data was requested or where available downloaded from official websites of the Federal States or River Basins. Different variables for NO3-N and TP were finally considered in the models to produce the RF, like discharge, land use, day of the year.
The German-Swiss Hillscape project focuses on the vertical and lateral redistribution of water and matter along hillslopes and how this redistribution is affected by soil, vegetation and landscape development. The overall research question of the project is: How does the hillslope feedback cycle evolve in the first 10,000 years and how is this related to the evolution of hillslope structure? In order to tackle this research question, chronosequences in alpine glacier forelands were selected and artificial rainfall experiments were conducted. These datasets specifically contain data at the interface of sediment transport and hillslope hydrology. Specifically, they contain data about changes in soil surface characteristics (saturated hydraulic conductivity for three soil depths, soil aggregate stability for the surface soil layer), overland and shallow subsurface flow (runoff characteristics as peak flow rates, duration of flow, runoff ratios, event water fractions) and sediment yield values for overland flow along the moraine chronosequence. We measured the near-surface hydrological characteristics of four moraines with different age on a carbonate glacier foreland (forefield of the Griessfirn, close to the Klausenpass alpine road) and silicate glacier foreland (glacier forefield of the Steingletscher, close to the Sustenpass alpine road). The ages of the four moraines were ~30, ~160, ~3000 and ~10000 years (Sustenpass) and ~80, ~160, 4900 and 13500 years (Klausenpass). We selected 3 plots (dimensions: 4m x 6m) on each moraine, based on the vegetation complexity (low, medium and high), to cover as much of the potential variability within each moraine as possible. The structural vegetation complexity was based on the vegetation cover, number of different species, and functional diversity (based on stem growth form, root type, clonal growth organ, seed mass, Raunkiaer’s life form, leaf dry matter content, nitrogen content and specific leaf area (Garnier et al., 2016). We measured the near-surface hydrological properties of each plot (the saturated hydraulic conductivity and the soil aggregate stability) because the properties are essential for the runoff response on each plot. The runoff response and its characteristics for each plot was determined for sprinkling experiments of different intensities and during natural rainfall events (only at Klausenpass). We used tracers (Deuteriumoxid and NaCl) that we added to the sprinkling water and took samples of the soil water, then rainfall and the runoff to perform a 3-end-member hydrograph separation, using the method of Gibson et al. (2000). With that, we were able to identify the mixing (e.g. event water fraction), storage and flow pathways of the overland flow and subsurface flow. We filtered the overland flow samples to define the total sediment flux per experiment.
This data set was taken within the Perturbations of Earth Surface Processes by Large Earthquakes PRESSurE Project (https://www.gfz-potsdam.de/en/section/geomorphology/projects/pressure/) of the GFZ Potsdam. This project aims to better understand the role of earthquakes on earth surface processes. Strong earthquakes cause transient perturbations of the near Earth’s surface system. These include the widespread landsliding and subsequent mass movement and the loading of rivers with sediments. In addition, rock mass is shattered during the event, forming cracks that affect rock strength and hydrological conductivity. Often overlooked in the immediate aftermath of an earthquake, these perturbations can represent a major part of the overall disaster with an impact that can last for years before restoring to background conditions. Thus, the relaxation phase is part of the seismically induced change by an earthquake and needs to be monitored in order to understand the full impact of earthquakes on the Earth system. Early June 2015, shortly after the April 2015 Mw7.9 Gorkha earthquake, 6 automatic compact weather station were installed in the upper Bhotekoshi catchment covering an area ~50km2. The weather station network is centered around the Kahule Khola catchment, a small headwater catchment and is part of a wider data acquisition strategy including hydrological monitoring, seismometers, geophones and high resolution optical (RapidEye) as well as radar imagery (TanDEM TerraSAR-X). https://www.gfz-potsdam.de/sektion/geomorphologie/projekte/pressure/
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