ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Geologic Sediments/chemistry  (2)
  • Bacteria/chemistry/cytology/isolation & purification/metabolism  (1)
  • AMK2-BCH-TR; Archive of Ocean Data; ARCOD; Cyclothones; Depth, bottom/max; Depth, top/min; DEPTH, water; Fishes; Fishes, other; Gonostomes; IKMT; Indian Ocean; Isaac-Kid-Midwater Trawl; Myctohids; Sternoptychidae; Vinciguerria
  • Chemistry
  • 2010-2014  (3)
Collection
Keywords
Publisher
Years
Year
  • 1
    facet.materialart.
    Unknown
    Organic-walled microfossils in 3.2-billion-year-old shallow-marine siliciclastic deposits (2010)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2010-02-09
    Description: Although the notion of an early origin and diversification of life on Earth during the Archaean eon has received increasing support in geochemical, sedimentological and palaeontological evidence, ambiguities and controversies persist regarding the biogenicity and syngeneity of the record older than Late Archaean. Non-biological processes are known to produce morphologies similar to some microfossils, and hydrothermal fluids have the potential to produce abiotic organic compounds with depleted carbon isotope values, making it difficult to establish unambiguous traces of life. Here we report the discovery of a population of large (up to about 300 mum in diameter) carbonaceous spheroidal microstructures in Mesoarchaean shales and siltstones of the Moodies Group, South Africa, the Earth's oldest siliciclastic alluvial to tidal-estuarine deposits. These microstructures are interpreted as organic-walled microfossils on the basis of petrographic and geochemical evidence for their endogenicity and syngeneity, their carbonaceous composition, cellular morphology and ultrastructure, occurrence in populations, taphonomic features of soft wall deformation, and the geological context plausible for life, as well as a lack of abiotic explanation falsifying a biological origin. These are the oldest and largest Archaean organic-walled spheroidal microfossils reported so far. Our observations suggest that relatively large microorganisms cohabited with earlier reported benthic microbial mats in the photic zone of marginal marine siliciclastic environments 3.2 billion years ago.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Javaux, Emmanuelle J -- Marshall, Craig P -- Bekker, Andrey -- England -- Nature. 2010 Feb 18;463(7283):934-8. doi: 10.1038/nature08793. Epub 2010 Feb 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geology, University of Liege, 17 allee du 6 Aout B18, Liege 4000, Belgium. ej.javaux@ulg.ac.be〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20139963" target="_blank"〉PubMed〈/a〉
    Keywords: Acids ; Bacteria/chemistry/cytology/isolation & purification/metabolism ; Carbon/analysis/chemistry ; Carbon Isotopes ; *Ecosystem ; Eukaryotic Cells/chemistry/cytology ; *Fossils ; Geologic Sediments/*microbiology ; History, Ancient ; Oceans and Seas ; Organic Chemicals/*analysis/chemistry ; *Phylogeny ; Reproducibility of Results ; Seawater/*microbiology ; South Africa ; Spectrum Analysis, Raman ; Sunlight
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    The evolution of the marine phosphate reservoir (2010)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2010-10-29
    Description: Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean-atmosphere system. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth's history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from approximately 750 to approximately 635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude 'snowball Earth' glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Planavsky, Noah J -- Rouxel, Olivier J -- Bekker, Andrey -- Lalonde, Stefan V -- Konhauser, Kurt O -- Reinhard, Christopher T -- Lyons, Timothy W -- England -- Nature. 2010 Oct 28;467(7319):1088-90. doi: 10.1038/nature09485.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, California 92521, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20981096" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aquatic Organisms/*metabolism ; Atmosphere/chemistry ; *Biological Evolution ; Ferric Compounds/analysis/metabolism ; Geologic Sediments/chemistry ; History, Ancient ; Ice Cover ; Iron/analysis/metabolism ; Marine Biology ; Oceans and Seas ; Oxidation-Reduction ; Oxygen/analysis/metabolism ; Phosphates/analysis/*metabolism ; Phosphorus/analysis/metabolism ; Seawater/chemistry ; Silicon Dioxide/analysis/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Widespread iron-rich conditions in the mid-Proterozoic ocean (2011)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2011-09-09
    Description: The chemical composition of the ocean changed markedly with the oxidation of the Earth's surface, and this process has profoundly influenced the evolutionary and ecological history of life. The early Earth was characterized by a reducing ocean-atmosphere system, whereas the Phanerozoic eon (less than 542 million years ago) is known for a stable and oxygenated biosphere conducive to the radiation of animals. The redox characteristics of surface environments during Earth's middle age (1.8-1 billion years ago) are less well known, but it is generally assumed that the mid-Proterozoic was home to a globally sulphidic (euxinic) deep ocean. Here we present iron data from a suite of mid-Proterozoic marine mudstones. Contrary to the popular model, our results indicate that ferruginous (anoxic and Fe(2+)-rich) conditions were both spatially and temporally extensive across diverse palaeogeographic settings in the mid-Proterozoic ocean, inviting new models for the temporal distribution of iron formations and the availability of bioessential trace elements during a critical window for eukaryotic evolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Planavsky, Noah J -- McGoldrick, Peter -- Scott, Clinton T -- Li, Chao -- Reinhard, Christopher T -- Kelly, Amy E -- Chu, Xuelei -- Bekker, Andrey -- Love, Gordon D -- Lyons, Timothy W -- England -- Nature. 2011 Sep 7;477(7365):448-51. doi: 10.1038/nature10327.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, California 92521, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21900895" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Evolution ; Geologic Sediments/chemistry ; History, Ancient ; Iron/*analysis/chemistry ; Oceans and Seas ; Seawater/*chemistry ; Sulfur/analysis/chemistry ; Sulfur Isotopes ; Time Factors
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...