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  • 1
    Electronic Resource
    Electronic Resource
    Why ’very shallow‘ lakes are more successful opposing reduced nutrient loads (1997)
    Springer
    Hydrobiologia 342-343 (1997), S. 269-284 
    Details
    ISSN: 1573-5117
    Keywords: shallow lakes ; eu-hypertroph ; Cyanobacteria ; morphometry ; mixing ; euphotic depth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract There are different approaches for classifying deep andshallowwaters using physically and ecologically derived parameters.Nevertheless, transition states make it difficult to definebordercrossing points between the two types of limnetic ecosystemsand todistinguish more precisely between different types of shallow,especially highly eutrophicated lakes. We contribute adetailedanalysis of different characteristics of shallow waters fromlakesin the Berlin/Brandenburg-region. In the catchment area of theriver Dahme in Eastern Brandenburg (Scharmützelsee-region)wefind mainly shallow and highly eutrophicated lakes, dominatedbyCyanobacteria. ’Very shallow‘ lakes of different morphometry andtopography are compared with ’medium shallow‘ or deeper lakesinthe region with similar loading characteristics for thefollowingproperties: morphometry, topography, theoretical retentiontime,mixing intensity, nutrient dynamics, external and internalloading,underwater light climate, zeu/zmix,phytoplankton development and oxygen budget. We found that’veryshallow‘ lakes in the region are more efficient in convertingtheavailable phosphorus into phytoplankton biomass because of theconstant and sufficient underwater light climate due to thefavourable relation of zeu and zmix. Weconclude that the regular mixing regime guarantees a stableandnear optimum light/dark rhythm as well as higher heterotrophicactivities, stimulating primary production up to the upperlimit ofalgal development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017012012099
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Polymixis of a shallow lake (Groβer Müggelsee, Berlin) and its influence on seasonal phytoplankton dynamics (1994)
    Springer
    Hydrobiologia 275-276 (1994), S. 173-186 
    Details
    ISSN: 1573-5117
    Keywords: polymixis ; phytoplankton growth ; cyanophyta ; diatoms ; nutrient stress ; mixing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The polymictic properties of Lake Müggelsee, a eutrophic shallow lake in Berlin, are described by the water column stability (N 2) and gradients in saturation of oxygen at the deepest site of the lake (7.5 m). Mixing and stratification changed irregularly up to 7 times during the vegetation season (April to September), as was indicated by all of the stratification parameters. Thermally stable conditions generally lasted 1–2 weeks. A maximum of 5 weeks stratification was observed in 1982. In order to investigate the response of algal development, the internal rates of change of the dominant algal species in the lake during the vegetation period were estimated from weekly measurements of phytoplankton biomass from 1980 to 1990. The necessity taking a mixed sample in a shallow lake is discussed. The polymictic properties favoured the development of specific blue-green algal species; there dominance was also favoured by the trophic conditions. Among the dominant blue-greens the growth of Limnothrix redekei was independent of polymixis whereas stratification supported the starting conditions for the summer blue-greens Aphanizomenon flos-aquae and Planktothrix agardhii. After these algae reached a distinct level of biomass, they grew under mixing as well as under stratified conditions. For the development of solitary centric diatoms during summer regulation by growth restriction through nutrient limitation, esp. dissolved silicon was more important. However, Melosira sp. developed well under stratified conditions but collapsed due to increased sinking losses when the water column became too stable. An attempt is made to apply Reynolds' possibility matrix of the most likely phytoplankton assemblages as a function of nutrients and mixing in the shallow Lake Müggelsee.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00026709
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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