The cycling of iron and organic matter (OM) is thought to have been a major biogeochemical cycle in the early ferruginous oceans which contributed to the deposition of banded iron formations (BIF). However, BIF are deficient in OM, which is postulated to be the result of near-complete oxidation of OM during iron reduction. We test this idea by documenting the prevalence of OM in clays within BIF and clays in shales associated with BIF. We find in shales >80% of OM occurs in clays, but <1% occurs in clays within BIF. Instead, in BIF OM occurs with C-depleted carbonate and apatite, implying OM oxidation occurred. Conversely, BIF which possess primary clays would be expected to preserve OM in clays, yet this is not seen. This implies OM deposition in silicate-bearing BIF would have been minimal, this consequently stifled iron-cycling and primary productivity through the retention of nutrients in the sediments.
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http://dx.doi.org/10.1038/s41467-019-12975-z | DOI Listing |
ACS Omega
December 2024
The Third Affiliated Hospital of Anhui Medical University, The First People's Hospital of Hefei, Anhui, Hefei 230000, China.
The challenge of healing diabetic skin wounds presents a significant hurdle in clinical practice and scientific research. In response to this pressing concern, we have developed a temperature-sensitive, in situ-forming hydrogel comprising poly(-isopropylacrylamide---butyl acrylate) -poly(ethylene glycol) -poly(-isopropylacrylamide--butyl acrylate) copolymer, denoted as PEP, in combination with zinc oxide nanoparticles, forming what we refer to as PEP-ZnO hydrogel. The antimicrobial properties of the PEP-ZnO hydrogel against methicillin-resistant were rigorously assessed by using the bacteriostatic banding method.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
December 2024
Division of Cardiology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
Right ventricular dysfunction (RVD) portends increased death risk for heart failure (HF) and pulmonary arterial hypertension (PAH) patients, regardless of left ventricular function or disease etiology. In both, RVD arises from chronic RV pressure overload and represents advanced cardiopulmonary disease. RV remodeling responses and survival rates of patients, however, differ by sex.
View Article and Find Full Text PDFNat Geosci
October 2024
School of Earth Sciences, University of Bristol, Bristol, UK.
Anoxygenic phototrophic Fe(II) oxidizers (photoferrotrophs) are thought to have thrived in Earth's ancient ferruginous oceans and played a primary role in the precipitation of Archaean and Palaeoproterozoic (3.8-1.85-billion-year-old) banded iron formations (BIFs).
View Article and Find Full Text PDFACS Omega
October 2024
Department of Chemistry, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut 1107 2020, Lebanon.
Liesegang patterns present a display of parallel stripes of precipitate that arise from the interdiffusion of coprecipitate ions in a gel medium. The bands observed in rocks are typical analogies of this phenomenon, and their composition is not restricted to the banded deposition of a single mineral. We here extend the study to a three-precipitate system, wherein Co, Ni, and Cd cations are precipitated by the same anion (OH from NHOH) to form Co(OH), Ni(OH), and Cd(OH), respectively.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
January 2025
Division of Cardiology, Labatt Family Heart Centre, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
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