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The influence of early diagenesis on the vertical distribution of metal forms in the sediments of Bohai Bay was discussed in this paper. The results showed that the concentrations were: Al > Fe ≈ Ca > Mn > Cr > Zn > Cu > Pb > Cd. In vertical distribution, the forms of Cr and Pb were stable from the top to the bottom. However, the exchangeable forms and acid-extracted forms of Cd, Cu and Zn presented an obvious declining trend. The metals would be transformed to more stable forms during the early-diagenesis process. Further analysis found that early diagenesis can change the sedimentary environment, affecting pH, oxidation-reduction potential (ORP), total dissolved solid (TDS) and the structure of organic matter (OM), all main factors influencing metal forms in the sediments of Bohai Bay.
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http://dx.doi.org/10.1016/j.marpolbul.2014.09.011 | DOI Listing |
Sci Rep
August 2025
Department of Earth and Planetary Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA.
Definitive evidence for the microbially induced smectite-to-illite (S-I) reaction has previously been shown using culture experiments with pure clay minerals, whereas recognition in nature remains difficult. Here, we investigated the microbially induced S-I reaction in natural sediments during laboratory compression and applied new and previously used techniques that can positively identify the products of this reaction. We performed resedimentation experiments without (control experiment) and with the Fe reducing bacteria Shewanella oneidensis MR-1 (microbially amended experiment) added to natural sediments collected from the Ursa and Brazos-Trinity regions in the Gulf of Mexico during Integrated Ocean Drilling Program Expedition 308.
View Article and Find Full Text PDFMicroorganisms
August 2025
LAMIR Institute, Graduate Program in Geology, Universidade Federal do Paraná, Curitiba 81531-980, Paraná, Brazil.
Extreme environments, such as hypersaline habitats, hot springs, deep-sea hydrothermal vents, glaciers, and permafrost, provide diverse ecological niches for studying microbial evolution. However, knowledge of microbial communities in extreme environments at high southern latitudes remains limited, aside from Antarctica. Laguna Timone is a hypersaline crater lake located in a Pleistocene maar of the Pali Aike Volcanic Field, southern Patagonia; the lake was formed during basaltic eruptions in a periglacial setting.
View Article and Find Full Text PDFACS Omega
July 2025
CSIR - Central Institute of Mining and Fuel Research, Dhanbad 826015, Jharkhand, India.
The cleat is a characteristic structural feature found within coal lithotypes, often in a regular pattern. The presence of cleats and fractures in coal is advantageous for miners, as they provide weak planes that aid in extraction. However, the stability of pillars and roofs relies on factors such as cleat/fracture orientation, spacing, and intensity.
View Article and Find Full Text PDFNature
July 2025
Globe Institute, University of Copenhagen, Copenhagen, Denmark.
In the past decade, ancient protein sequences have emerged as a valuable source of data for deep-time phylogenetic inference. Still, even though ancient proteins have been reported from the Middle-Late Miocene, the recovery of protein sequences providing subordinal-level phylogenetic insights does not exceed 3.7 million years ago (Pliocene).
View Article and Find Full Text PDFNature
July 2025
Museum Conservation Institute, Smithsonian Institute, Suitland, MD, USA.
Research into the palaeobiology of extinct taxa through ancient DNA and proteomics has been mostly limited to Plio-Pleistocene fossils, due to molecular breakdown over time, which is exacerbated in tropical settings. Here we sample small proteomes from the interior enamel of fossils at palaeontological sites from the Pleistocene to the Oligocene in the Turkana Basin, Kenya, which has produced a rich record of Cenozoic mammalian evolution. Through a mass-spectrometry-based proteomic workflow, and using criteria to locate diagenetiforms derived from enamel, we recover fragments of enamelin, ameloblastin, matrix metalloprotease-20 and dentin matrix acidic phosphoprotein 1 from an Early Miocene rhinocerotid and several proboscideans collected from the sites of Buluk (16 million years ago; Ma) and Loperot (18 Ma).
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