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  • 11
    Electronic Resource
    Electronic Resource
    The state of freshwater ecology (1998)
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 39 (1998), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The case is advanced that freshwater ecologists need to champion the relevance of their work to the development of ecological theory and to the understanding of ecosystem function and behaviour, not least for its importance in addressing pressing applications to the stewardship of the biosphere. An essential step is to review, and update where necessary, the paradigms of aquatic ecology.2. It is proposed that the major constraint on the organisms, their attributes and adaptations are related first to the physical properties of the medium in which they live. The drives to grow and reproduce relate to the trophic transfer of reduced carbon with important microbial interventions. General principles of ‘emergy’ apply. The supportive capacities of given environments may be set by chemical constraints, but it is suggested that, with the exception of chronically resource-deficient waters, population dynamics relate to opportunities incumbent upon system variability and the consequent pulsation of resources.3. Variability affects diversity, through frequent revision of the thermodynamic base. Frequent structural change promotes species diversity and, because function is maintained, it appears that efficient function is dependent upon high diversity. Caution is necessary because high productivity and high diversity are both products of the disturbances consequent upon external forcing and manifestly non-equilibrium conditions.4. Reactions to these statements are canvassed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2427.1998.00315.x
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  • 12
    Electronic Resource
    Electronic Resource
    Modelling the effects of artificial mixing and copper sulphate dosing on phytoplankton in an Australian reservoir (2003)
    Oxford, UK : Blackwell Science, Ltd
    Lakes & reservoirs 8 (2003), S. 0 
    Details
    ISSN: 1440-1770
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography
    Notes: An artificially destratified reservoir was simulated with the freshwater phytoplankton model PROTECH (Phytoplankton Responses To Environmental Change). The chosen site for validation was a highly managed drinking water supply reservoir (Myponga Reservoir, South Australia). Chemical dosing using copper sulphate (CuSO4) and artificial mixing via an aerator and two raft-mounted mechanical surface mixers (hereafter referred to as surface mixers) are used at Myponga to manage water quality, in particular the threat of cyanobacteria growth. The phytoplankton community was adequately modelled and showed that the community was dominated by species tolerant of low light doses (R-type strategists). The light limitation in the water body was found to be the controlling factor on phytoplankton succession. Subsequently, small fast-growing species and larger motile phytoplankton (C and CS-type, respectively) do not have the opportunity to dominate under all simulated conditions, diminishing the need for CuSO4 dosing. These simulations demonstrated that the individual and combined impact of the management strategies reduces the total algal biomass, but have minimal effect upon phytoplankton functional-type succession, and R-type species continued to dominate under all simulated scenarios. It was concluded that, due to the light-limitation and current nutrient availability in Myponga Reservoir, the probability of persistent populations of undesirable scum-forming cyanobacteria is minimal, even in the absence of artificial control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1770.2003.00209.x
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  • 13
    Electronic Resource
    Electronic Resource
    Metabolic sensitivities of lacustrine ecosystems to anthropogenic forcing (1999)
    Springer
    Aquatic sciences 61 (1999), S. 183-205 
    Details
    ISSN: 1420-9055
    Keywords: Key words: Lakes, trophic state, system metabolism, carbon-based stoichiometry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract: Present perceptions of trophic status are reviewed and considered wanting against the early Thienemann-Naumann classification based on lake metabolism. This theme is developed through a consideration of the supportive capacities defined by the supplies of each of the main anabolic components and by the processing of fixed carbon through the water column and in the superficial sediments. The import of external organic carbon is acceptable within the oxidative capacity of the aquatic system but an excess challenges its conventional sustainability. A recent application of metabolic modelling to the management of a lake subject to anthropogenic influences is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000270050061
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  • 14
    Electronic Resource
    Electronic Resource
    Phytoplankton periodicity and sequences of dominance in an Amazonian flood-plain lake (Lago Batata, Pará, Brasil): responses to gradual environmental change (1997)
    Springer
    Hydrobiologia 346 (1997), S. 169-181 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton ; succession ; flood-plain lake ; Amazon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The composition of the phytoplankton of Lago Batata,a flood-plain lake connected to Rio Trombetas,undergoes a conspicuous annual cycle which is relatedto the hydrology (depth of water, rate of fluvialflushing) and the hydrography (stability, frequency ofmixing of the water) of the lake. From a sparsenanoplankton at high-water and high flushing, the lakepasses to desmid-diatom dominance and finally tofilamentous cyanobacteria when the lake is barely 2 mdeep. As it refills, the lake again becomes desmid-dominated; then, when the turbidity is least and thestratification most stable, Botryococcus becomesa major component. Eventually flushing becomes toorapid for any but the relatively fastest-growingspecies. These changes are gradual and, at the scaleof algal generation times, cannot be explained assharp or sudden disturbances. Neither do they have theproperties of ecological successions but ratherrepresent compositional responses to a progressiveenvironmental modification analogous to the floristicphenomenon of gradual climate change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1002926318409
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  • 15
    Electronic Resource
    Electronic Resource
    Scales of disturbance and their role in plankton ecology (1993)
    Springer
    Hydrobiologia 249 (1993), S. 157-171 
    Details
    ISSN: 1573-5117
    Keywords: succession ; phytoplankton ; equilibrium ; intermediate disturbance ; diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of hydraulic and hydrographic disturbances in delaying, arresting or diverting successional sequences from achieving stable, climactic equilibria is discussed by reference to case studies. The critical time scale is expressed in terms of planktonic reproductive generation times. Environmental constancy persisting over some 12–16 generations may permit a climactic condition to be achieved. An Intermediate Disturbance, if sustained, can establish a new successional sequence or, if not, can lead to a reversion to a sequence similar to the predisturbance succession. At intervals of ∼ 1 generation time, species are selected according to their ability to accommodate disturbances at the physiological level. Highly disturbed environments are considered to be likely to maintain ‘plagioclimactic’ associations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008851
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  • 16
    Electronic Resource
    Electronic Resource
    Selection of phytoplankton associations in Lake Balaton, Hungary, in response to eutrophication and restoration measures, with special reference to the cyanoprokaryotes (1998)
    Springer
    Hydrobiologia 384 (1998), S. 41-53 
    Details
    ISSN: 1573-5117
    Keywords: Biomass ; cyanoprokaryota ; floristic change ; eutrophication ; restoration ; shallow lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Restoration of shallow lakes degraded by eutrophication has often been protracted as a consequence of the accumulation and subsequent releases of phosphorus in their sediments (internal load). Balaton, the largest shallow lake in Central Europe, underwent rapid eutrophication during the 1960s–1970s, during which a west-east gradient of trophic state developed. Measures to reverse the eutrophication and to restore the lake to its historic quality were initiated in the mid-1980s. The external phosphorus load has been decreased considerably but the responses of the phytoplankton have been slight and sometimes counterintuitive. At the level of total biomass, the erstwhile distinctiveness of the down-lake trophic gradient has weakened. The eukaryotic plankton flora has altered little but floristic changes in the dominant cyanoprokaryota are consistent with environmental changes attributable to the eutrophication and subsequent restoration. The dominant species are shown to have been consistently related to variables including sediment-water interactions, physical disturbances and the specific biotic adaptations of the organisms but the phytoplankton development in given years and in given parts of the lake has fluctuated with the stochasticity of the weather. In some years, hypertrophic conditions have continued to develop, marked by the development of prolific cyanoprokaryote blooms; in other years, phytoplankton biomass scarcely exceeded a mesotrophic level, with a species composition resembling that which obtained prior to the recent eutrophication. The species associations represented are believed to be consistent with the responses of groups of species observed elsewhere, suggesting that the patterns of community assembly in the phytoplankton are potentially predictable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003255529403
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