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  • Portugal  (1)
  • diversity  (1)
  • long-term changes  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Long-term changes in the diversity and faunal structure of benthic communities in the northern North Sea: natural variability or induced instability? (1998)
    Springer
    Hydrobiologia 375-376 (1998), S. 317-329 
    Details
    ISSN: 1573-5117
    Keywords: North Sea ; benthic communities ; variability ; natural disturbance ; dominance ; diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in benthic sedimentary communities in many areas of the northern North Sea in the vicinity of oil and gas fields have been monitored intermittently over the past three decades, in most cases triennially but in some areas annually for short periods. Accumulating evidence from these surveys suggests that large scale temporal variability occurs in both the diversity and structure of these communities on time scales varying from years to decades. A recent change to regional, rather than field based, surveys in the Norwegian sector of the North Sea has provided evidence that spatially such changes occur on broad scales and are not local responses to field based environmental disturbance. The possible factors inducing such changes are reviewed and the relative temporal and spatial stability of benthic infaunal communities in response to fluctuating pelagic conditions and levels of sedimentary disturbance are discussed. It is suggested that broad scale temporal and spatial variability in these benthic communities is driven by climatic forces influencing the overlying water masses but that there may have been some increase in pelagic productivity and/or in benthic pelagic coupling in the area in recent years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017009022463
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Long term changes in the benthic communities of Loch Linnhe and Loch Eil (Scotland) (1986)
    Springer
    Hydrobiologia 142 (1986), S. 113-119 
    Details
    ISSN: 1573-5117
    Keywords: long-term changes ; benthos ; organic enrichment ; temperature anomalies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Population fluctuations over a twenty year period in the macrobenthic communities of Loch Linnhe and Loch Eil, on the western coast of Scotland, are related to changing organic inputs to the area and to long-term temperature changes. It is suggested that the carrying capacity of sedimentary benthos is dependent on organic input, but that the species composition of the communities may be modified by climatic fluctuations acting on the spawning success and subsequent recruitment of particular species. Confirmation of such hypotheses generated from field time-series data should be obtained by experimentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00026751
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Sediment chemistry — Infaunal community structure in a southern European estuary related to solid-phase Microtox® toxicity testing (1995)
    Springer
    Aquatic ecology 29 (1995), S. 427-436 
    Details
    ISSN: 1573-5125
    Keywords: Sediment toxicity ; bioluminescent bacteria ; sediment contamination ; macrofaunal communities ; Sado estuary ; Portugal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper presents the results from a sedimentary survey undertaken in July 1992 in the Sado estuary, western coast of Portugal. Sediment samples were taken at 14 sites, corresponding to four organic enrichment gradients, three of which are located close to harbour facilities or to industrial or urban effluent outfalls. The fourth site is located away from direct sources of anthropogenic disturbance. An integrated approach was conducted in order to study the quality status of the superficial sediments, and included 1. the analysis of sediment descriptors and contaminants (grain-size, total organic matter, heavy metals, PCBs), 2. the evaluation of toxicity, using bioluminescent bacteria and the Microtox® solid-phase protocol and 3. the study of macrofaunal communities structure and composition. Most of the sediments showed low IC50 values (high toxicity), while benthic macrofauna did not indicate community disturbance in most of the sites, nor the contaminants analysed provided explanation for the potential toxicity observed. Most of the sediments showed high fines content. A statistical significant relation between fines and IC50 values was found, indicating the sensitivity of the toxicity assessment method for granulometry. This sensitivity might explain the lack of agreement between the IC 50 values and the sediment chemistry-infaunal communities structure. The potential grain-size sensitivity was further analysed using another test sediment from which artificial samples with different sand∶fines ratios were prepared. It is concluded that extreme caution should be used when applying the solid-phase Microtox® protocol to assess the toxicity of natural sediments, covering a range of granulometry and contamination situations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02084241
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    Paper (German National Licenses)
    Fulltext
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