This data collection contains new observations of sediment color, mineral‑geochemical properties, and benthic foraminiferal stable isotopes that characterise "green bands" in Quaternary marine sediments and evaluate their value as markers of deep‑ocean ventilation changes. Parameters reported include (i) benthic foraminifera δ¹⁸O and δ¹³C (species Cibicidoides wuellerstorfi and Uvigerina spp.), (ii) down‑core colour information extracted from high‑resolution digital core photographs, expressed as green‑pixel percentages for a set of hue–saturation–value (HSV) bins, (iii) X‑ray‑fluorescence (XRF) core‑scan elemental ratios (e.g. Fe/Ti, Si/Al), (iv) pyrite counts in >63 µm coarse fractions, and (v) ancillary site‑characterisation variables such as sedimentation rate, bulk CaCO₃, organic‑carbon content, bottom‑water [O₂], and satellite‑derived export productivity. Sediments span 0–1.2 Ma for Site U1474 and Site U1313, with depth/age tie points listed in Tables S2. Primary data derive from International Ocean Discovery Program (IODP) Sites U1474 (Southwest Indian Ocean; 31°13.00′S, 31°32.71′E, 3045 below sea level) and (North Atlantic; 41°0.068'N, 32°57.439'W, 3412 meters below sea level). The accompanying global survey (Table 3) covers observations from the first core of 2122 holes collected since the inception of the Deep Sea Drilling Program, covering all major ocean basins. Green colour banding has been linked to redox fronts associated with bottom‑water ventilation; quantifying its stratigraphic occurrence may provide an easily transferable proxy for past oxygenation. The dataset supports tests of that hypothesis and enables reuse in broader studies of sediment diagenesis, colour imaging, and benthic δ¹³C. Benthic foraminiferal δ¹⁸O and δ¹³C were measured on Cibicidoides wuellerstorfi and Uvigerina peregrina picked at 12 cm (≈ 3 kyr) intervals from the >150 µm fraction of 400 samples down to 48 m at IODP Site U1474. Analyses used a Thermo Finnigan MAT 253 IRMS coupled to a Kiel IV carbonate device at Cardiff University; long‑term external precision is ±0.05 ‰ for δ¹⁸O and ±0.021 ‰ for δ¹³C (1 σ) and results are reported relative to VPDB after calibration to internal standard BCT63 and application of standard vital‑effect offsets (+0.64 ‰ for Cibicidoides, 0 ‰ for Uvigerina). A Site U1474 δ¹⁸O stack was generated by averaging species‑specific values and tuning the composite record to the LR04 stack for age control. To assess the spatial occurrence of colour banding, we screened 2 121 split‑core photographs (first 1.5 m of piston cores) from all IODP expeditions via Texas A&M's LIMS archive, noting the depth (< 40 cm or > 40 cm) and character of oxidative colour transitions. Environmental parameters (bottom‑water O₂, export productivity, sedimentation rate, bulk CaCO₃, organic C) were extracted from published global grids and compared with banding frequency. For Sites U1474 and U1313, relic green bands were mapped with a computer‑vision workflow in Python. Split‑core images (native resolution ≈ 50 µm px⁻¹) were analysed with OpenCV's inRange filter: HSV colour space (H 0–360, S/V 0–100) was divided into 3 600 ten‑unit cubes, narrowed to 627 sediment‑relevant hues guided by Munsell chips, and the 20 most selective "green" cubes were retained. Summed depth‑series ("green‑pixel %") were smoothed and peaks delineated with SciPy's prominence‑based algorithm (prominence 9/7, distance 1/10 points for U1474/U1313), then manually quality‑controlled. Sand layers identified from core photographs and Si/Al XRF scans (Avaatech, 30 kV, 200 µA, 10 s, 2 mm beam) were masked before colour analysis. Finally, a 14‑site global benthic δ¹³C stack was compiled by standardising, 5 ka‑smoothing, and averaging published depth‑age–resolved records (Atlantic, Indian, Pacific basins) together with the new U1474 data.
Benthic carbon isotope stack and constituent carbon isotope records. Numbered columns represent sites with carbon isotope records resampled at 1 ka resolution. Stack: The average of the standardized individual carbon isotope records 1s: A 1 standard deviation envelope for the stack based on variance within the standardized records. Filt: The carbon isotope record filtered with a 400 ka bandpass filter
Removal rates of many pollutants in lake water are controlled by their partition between dissolved, colloidal and particulate fractions. We are investigating this partition using natural radioactive Be isotopes as surrogates for these pollutants. A new particle separation system for big lake water samples (1000 liters) consisting of a continuous flow centrifuge and an ultra filtration device has been developed. In epilimnion of Lake Lugano we are able to measure Be-7 in all 3 fractions. The largest part is found in the dissolved fraction. This may explain the relatively long residence time of Be in lakes. The work has been accompanied by a series of methods aimed at characterising the physico-chemical conditions in the lake at the time of sampling, the nature of the recovered particles, as well as the performance of the system. Electron microscope observations show decreasing number of particles and their sizes from raw to centrifuged and to ultra filtered water. Pilot measurements to study particle dynamics in the deep water have been carried out including tritium-helium water age measurements. Leading Questions: - What is the role of colloids in removal of metals and radionuclides from lake water? - Can Be-7 be used to determine coagulation rate in lakes? - What is the importance of Fe and Mn cycling at redox interface in permanently stratified lake for phosphorous transport? Other objectives of this project are the following: - Determine the role and importance of Fe and Mn cycling at the oxic-anoxic interface for phosphorous fluxes, - assess the nature of fine particles in lower hypolimnion and their transport mechanism (coagulation, settling, resuspension, focusing)?
The sustainable management of land, which has been heavily contaminated by industrial or mining activities, poses an important challenge to many industrialized countries, including Bulgaria. This project focuses on arsenic (As) contamination in NW Bulgaria, where the floodplains of the Ogosta river received large amounts of As-rich mining wastes near Chiprovtsi between 1964 and 1979. The goals of the project are (i) to investigate the magnitude and spatial distribution of As contamination in floodplain soils and sediments in relation to river system dynamics, (ii) to improve the process-oriented understanding of As release from soils to river and groundwater by microbial and physico-chemical processes during periods of low and high flow, and (iii) to explore advanced approaches for integrating process-oriented, molecular scale knowledge and river-system scale information to better understand As speciation, As fluxes, and impacts on water quality at the river-system scale. The project is expected to yield novel process-oriented knowledge on the dynamics of As in highly contaminated river floodplains. New ways of integrating molecular-scale and river-system scale information will be explored, which can then also be applied to other river systems in Bulgaria. The project will provide the scientific basis for river management and potential remediation strategies for Ogosta river. Ultimately, it will help protect the local population from adverse health effects arising from the legacy pollution with As and other heavy metals by former mining.
Ziel des Projektes ist die Charakterisierung der Stoffdynamik in unterschiedlichen Milieubereichen des Grundwasserleiters an der Kontaktzone zwischen einem anoxischen Aquifer und dem oxischen Grabensystem des Oderbruchs. Der Einfluss der Graeben auf die hydrochemische Ausbildung des Grundwassers ist auf Grund der extremen hohen Gradienten qualitativ und quantitativ schwer zu beurteilen. Durch Untersuchungen im Gelaende mit einer genauen hydrochemischen und hydraulischen Charakterisierung der vorhandenen Redoxzonen in Verbindung mit experimentellen Saeulenversuchen im Labor werden die in den Redoxuebergangsbereichen ablaufenden Prozesse detailliert untersucht und eine Bilanzierung der Stoffumsetzungen durchgefuehrt. Die Arbeiten sollen Aussagen ueber die Langzeitwirkung der Senke/Quelle 'Redoxfront' machen.
Es werden Kläranlagendaten und Wasser- und Luftemissionen erfasst.
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