One year after the first filling stage of the Three Gorges Reservoir(TGR), dissolved inorganic mercury (Hg(DI)) was measured in August 2004. Concentration of Hg(DI) varied from undetection to 82.6 ng x L(-1) with average of 22.7 ng x L(-1). Stratification of Hg(DI) in the TGR was obviously. Concentrations of Hg(DI) were much higher in the layers above 20 m than in deep waters. Concentration of Hg(DI) in the Xiangxi River varied from undetection to 61.4 ng x L(-1) with average of 18.0 ng x L(-1). The Hg(DI) concentration increased obviously after the filling of the TGR. Large amount of Hg was retented with the deposition of sediment in the TGR. The retention of Hg by the TGR needs the further research.
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This case study of Kongsfjorden, western coastal Svalbard, provides insights on how freshwater runoff from marine- and land-terminating glaciers influences the biogeochemical cycles and distribution patterns of carbon, nutrients, and trace elements in an Arctic fjord system. We collected samples from the water column at stations along the fjord axis and proglacial river catchments, and analyzed concentrations of dissolved trace elements, together with dissolved nutrients, as well as alkalinity and dissolved inorganic carbon. Statistical tools were applied to identify and quantify biogeochemical processes within the fjord that govern the constituent distributions.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Solid State Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
The most commonly used homogeneous catalyst for fatty acid esterification is a corrosive sulphuric acid. However, this requires costly investment in non-corrosive equipment, presents a safety risk, is time consuming, and increases effluent generation. In this study, inorganic 3D heteroborane cluster strong acids are employed for the first time as homogeneous catalysts.
View Article and Find Full Text PDFSci Total Environ
January 2025
Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China.
Lake eutrophication driven by excessive nutrient inputs has become a global issue, but the potential impact of lacustrine groundwater discharge (LGD) as a nutrient source on lake eutrophication remains largely unknown. This study assessed the contribution of LGD-derived nutrient loads and revealed their potential impact on lake eutrophication in Taihu Lake, a typical large shallow and eutrophic lake in China, based on the segmented radon mass balance model and nutrient data. The total LGD flux was estimated to be 6.
View Article and Find Full Text PDFMar Environ Res
December 2024
School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China.
Diazotrophs have made significant contributions to marine nitrogen cycles. However, their distribution patterns and determined mechanisms have not been fully understood, particularly at the small regional scales. Here, the diazotrophic community structure by different sample sizes (0.
View Article and Find Full Text PDFSci Rep
January 2025
Grant Institute, School of Geosciences, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE, UK.
Glendonites (from the precursor of ikaite, CaCO.6HO) preferentially precipitate within sediments in cold waters (- 2 to 7°C) via either organotrophic or methanogenic sulphate reduction. Here, we report the first occurrence of possible glendonites associated with the end Permian mass extinction in the earliest Triassic (ca.
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