The polar oceans play a vital role in regulating atmospheric CO concentrations (pCO) during the Pleistocene glacial cycles. However, despite being the largest modern reservoir of respired carbon, the impact of the subarctic Pacific remains poorly understood due to limited records. Here, we present high-resolution, Th-normalized export productivity records from the subarctic northwestern Pacific covering the last five glacial cycles.
View Article and Find Full Text PDFMar Pollut Bull
November 2023
In this study, the sources of nine heavy metals (Cd, As, Hg, Cu, Pb, Ni, Cr, Zn, and Co) in the sediments of the Bohai Sea were quantitatively identified through a positive factor matrix to provide better advice for marine and coastal management. In Bohai Sea sediments, most metals fell below detectable contamination levels, including As, Cu, Pb, Ni, Cr, Zn, and Co. Unfortunately, Bohai Sea sediments were moderately to significantly enrich with Cd and Hg, posing potentially adverse ecological risks to aquatic ecosystems.
View Article and Find Full Text PDFJ Colloid Interface Sci
March 2023
Background metal concentrations are important in assessing pollution level of marine sediments; however, they can be significantly altered by local depositional environments, resulting in significant errors in regional pollution assessment. This study was based on the investigation of the background levels of heavy metals in the Bohai Sea sediments using sediment core, 2-sigma outlier, and regression methods. We also estimate the ecological risks of heavy metals for surface sediments collected from the Bohai Sea using the three methods mentioned above.
View Article and Find Full Text PDFStudies have reported that various hydrocarbons and hydrocarbon-degrading bacteria are found in global deep-sea hydrothermal regions. However, little is known about degradation characteristics of culturable hydrocarbon-degrading bacteria from these regions. We speculate that these bacteria can be used as resources for the bioremediation of oil pollution.
View Article and Find Full Text PDFThe heavy metal contents (Cr, Cu, Zn, Cd, Pb, Hg, and As) of 88 surface sediment samples from the western Sunda Shelf were analyzed to determine their spatial distribution patterns and contamination status. The results demonstrated that high enrichment regions of heavy metals were focused in the Kelantan, Pahang, and Ambat river estuaries, and deep water regions of the study area. These high enrichment regions were mainly controlled by riverine inputs and their hydrodynamic conditions.
View Article and Find Full Text PDFIn this study, sediments were collected from two different sites in the deep-sea hydrothermal region of the South Atlantic Ocean. Two microbial enrichment cultures (H7S and H11S), which were enriched from the sediments collected at two sample sites, could effectively degrade petroleum hydrocarbons. The bacterial diversity was analyzed by high-throughput sequencing method.
View Article and Find Full Text PDFAnthropogenic activities have increased lead (Pb) emissions and impacted their spatiotemporal distributions in coastal seas. To quantify the increasing variability of Pb and identify the specific origins and their corresponding magnitudes, Pb and Pb isotopes are investigated in a well-placed sediment core covering the period of 1928-2008 in the Central Yellow Sea Mud (CYSM). The concentration of Pb varied from 27.
View Article and Find Full Text PDFIn this study, we analyzed heavy metals in 404 surface sediment samples from the Bohai Sea to measure contamination status and distribution. We found Zn levels to be the highest, whereas Hg concentrations were the lowest of measured heavy metals. We found that the samples containing the most heavy metals were those collected from Fuzhou Bay, Jinzhou Bay, central Bohai Sea mud area, and the Yellow River Delta.
View Article and Find Full Text PDFThe present study aims to examine the distribution, sources and potential risks of toxic metals in the northern Bay of Bengal, Bangladesh. We found Cu, Pb, Zn and Hg exhibited similar spatial distribution pattern. Influenced by the Ganges-Brahmaputra River and the Karnafuli River, there were higher concentrations of these metals associated with the finer sediment and higher TOC in the northeastern portion of the study area.
View Article and Find Full Text PDFMagnetic iron-titanium binary oxide as an effective adsorbent for arsenic contaminant is a challenge primarily because of their bulk structure and agglomeration effect. Herein, a novel and uniform sandwich-like magnetic FeO@TiO sheets were synthesized by utilizing a facile strategy involving amorphous-to-crystalline transformation and reduction in H, to achieve dispersed anatase TiO nanoparticles with a small size of ∼8 nm anchored on FeO sheets. The resultant FeO@TiO sheets nanocomposite possessing a high specific surface area of ∼89.
View Article and Find Full Text PDFSelf-recoverable Pd-Ru/TiO2 nanocatalysts have been prepared by electrochemical stripping of Pd-Ru/TiO2 precursors. For the ethanol oxidation reaction (EOR), these Pd-Ru/TiO2 nanocatalysts are used as an anode catalyst. The characterization of catalysts via chronoamperometry has been repeated 15 times.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2017
The colorimetric biosensors have attracted intensive interest; however, their relatively low sensitivity limits their applications in clinic detection. Herein, we develop an effective colorimetric biosensor based on highly catalytic active Au nanoparticle-decorated BiSe (Au/BiSe) nanosheets. Au/BiSe nanosheets are facilely synthesized by simply sonicating Au precursor with the as-synthesized BiSe nanosheets in aqueous solution.
View Article and Find Full Text PDFGeochemical sources, spatio-temporal distribution, and associated environmental risk of Cd in the Bohai Sea were investigated using data from 405 surface sediment samples and two sediment cores. Local point Cd sources, TOC content, and currents are the main controlling factors of Cd distribution. The contribution of Cd from river discharge surpasses that from atmospheric deposition.
View Article and Find Full Text PDFWe developed a nanoscale Kirkendall effect assisted method for simple and scalable synthesis of three-dimensional (3D) Fe2O3 hollow nanoparticles (NPs)/graphene aerogel through the use of waste seaweed biomass as new precursors. The Fe2O3 hollow nanoparticles with an average shell thickness of ∼6 nm are distributed on 3D graphene aerogel, and also act as spacers to make the separation of the neighboring graphene nanosheets. The graphene-Fe2O3 aerogels exhibit high rate capability (550 mA h g(-1) at 5 A g(-1)) and excellent cyclic stability (729 mA h g(-1) at 0.
View Article and Find Full Text PDFTwo novel lanthanide selenidoarsenates(v) [Ln(dien)2(micro(3)-AsSe(4))] (Ln = Nd 1, Sm 2, dien = diethylenetriamine) were synthesized by the reactions of As(2)O(3) and Se with Nd(2)O(3) or Sm(2)O(3) in dien under solvothermal conditions. 1 and 2 are in the orthorhombic crystal system with Iba2 and Pbca space groups, respectively. The [AsSe(4)](3-) anion acts as a tridentate micro(3)-AsSe(4) ligand to bridge the lanthanide [Ln(dien)2](3+) complexes leading to one-dimensional neutral [Ln(dien)(2)(micro(3)-AsSe(4))](infinity) chains.
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