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  • 1
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    Abundance of pteropods in the south and west of South Georgia (2014)
    PANGAEA
    Details
    Publication Date: 2023-01-13
    Keywords: Abundance per volume; Date/Time of event; Depth, bottom/max; Depth, top/min; DEPTH, water; Event label; Latitude of event; Longitude of event; Net; NET; Scotia Sea, South Georgia; SG_T1-T9_2004; SG_T1-T9_2005; Taxon/taxa; Type; Uniform resource locator/link to reference
    Type: Dataset
    Format: text/tab-separated-values, 48 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
    Electronic Resource
    Electronic Resource
    The role of trace metals in photosynthetic electron transport in O2-evolving organisms (1999)
    Springer
    Photosynthesis research 60 (1999), S. 111-150 
    Details
    ISSN: 1573-5079
    Keywords: calcium ; copper ; iron ; manganese ; oxygen evolution ; phylogeny ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron is the quantitatively most important trace metal involved in thylakoid reactions of all oxygenic organisms since linear (= non-cyclic) electron flow from H2O to NADP+ involves PS II (2–3 Fe), cytochrome b6-f (5 Fe), PS I (12 Fe), and ferredoxin (2 Fe); (replaceable by metal-free flavodoxin in certain cyanobacteria and algae under iron deficiency). Cytochrome c6 (1 Fe) is the only redox catalyst linking the cytochrome b6-f complex to PS I in most algae; in many cyanobacteria and Chlorophyta cytochrome c6 and the copper-containing plastocyanin are alternatives, with the availability of iron and copper regulating their relative expression, while higher plants only have plastocyanin. Iron, copper and zinc occur in enzymes that remove active oxygen species and that are in part bound to the thylakoid membrane. These enzymes are ascorbate peroxidase (Fe) and iron-(cyanobacteria, and most al gae) and copper-zinc- (some algae; higher plants) superoxide dismutase. Iron-containing NAD(P)H-PQ oxidoreductase in thylakoids of cyanobacteria and many eukaryotes may be involved in cyclic electron transport around PS I and in chlororespiration. Manganese is second to iron in its quantitative role in the thylakoids, with four Mn (and 1 Ca) per PS II involved in O2 evolution. The roles of the transition metals in redox catalysts can in broad terms be related to their redox chemistry and to their availability to organisms at the time when the pathways evolved. The quantitative roles of these trace metals varies genotypically (e.g. the greater need for iron in thylakoid reactions of cyanobacteria and rhodophytes than in other O2-evolvers as a result of their lower PS II:PS I ratio) and phenotypically (e.g. as a result of variations in PS II:PS I ratio with the spectral quality of incident radiation).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006282714942
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    Paper (German National Licenses)
    Fulltext
  • 3
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    Seasonal and spatial dynamics of iron availability in the Scotia Sea (2012)
    Elsevier
    In:  Marine Chemistry, 130-131 . pp. 62-72.
    Details
    Publication Date: 2017-10-24
    Description: The Southern Ocean is the world's largest high nutrient low chlorophyll (HNLC) region. However, satellite images highlight several areas associated with island chains and shallow topographic features which display high phytoplankton biomass. Here we present the first study of seasonal variations in phytoplankton biomass and iron availability in the Scotia Sea over both austral spring and summer seasons. Based on dissolved iron (dFe) and Chlorophyll a (Chl a) concentrations, the study area is be divided into three regions: North of South Georgia, south of South Georgia and the vicinity of South Orkney Islands. The Scotia Sea to the south of South Georgia exhibited low dFe concentrations (〈0.027-0.05 nM) in surface waters during both the spring and summer seasons. Nevertheless, nitrate concentrations were considerably lower in spring compared to summer (difference similar to 8 mu M). Summer Chl a concentrations were similar to 1.4 mg m(-3) and in situ phytoplankton populations displayed evidence of iron stress, suggesting the development of seasonal iron limitation. Surface water dFe concentrations in the South Georgia bloom waters (north of the islands) were elevated and slightly lower during spring than summer (0.20 nM compared to 0.31 nM, P 〉 0.05). Nitrate concentrations were 16 mu M lower in summer compared to spring, whilst Chl a standing stocks remained high. Enhanced dFe (similar to 0.25 nM) and Chl a concentrations were furthermore observed in the vicinity of the South Orkney Islands, located in the southern Scotia Sea. Iron addition experiments showed that in situ phytoplankton were iron replete spring and summer north of South Georgia and in the vicinity of South Orkney Islands during summer. We thus suggest that increased iron supply in high productivity areas including the area north of South Georgia and the South Orkney Islands, was sustained by a continuous benthic supply from their shelf systems, with a potential additional input from seasonally retreating sea ice in the South Orkney system
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.marchem.2011.12.004
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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