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  • phytoplankton  (4)
  • mixing  (2)
  • acidification  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Chrysophytes and chlamydomonads: pioneer colonists in extremely acidic mining lakes (pH 〈3) in Lusatia (Germany) (1998)
    Springer
    Hydrobiologia 369-370 (1998), S. 315-327 
    Details
    ISSN: 1573-5117
    Keywords: acidic mining lakes ; phytoplankton ; Chlamydomonas ; Ochromonas ; water chemistry ; limiting factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-three extremely acidic (pH between 2.5 and 3.5) mining lakes in Lusatia (Germany) were analysed in order to classify their hydrochemistries and to assist the understanding of phytoplankton colonization of these extreme environments. Neither morphometric nor physical parameters influence phytoplankton composition but determine the extent to which the nutrient supply supports the mass development of Chrysophyceae and Chlorophyceae in certain layers of the water (hypo- or epilimnetic chlorophyll maxima and short mass developments). Conventional trophic classification is not readily applicable to these lakes but a chemical classification on the basis of hydrogen, total iron and acidity is proposed. Species of Ochromonas and Chlamydomonas dominate the phytoplankton in fourteen of the most acid lakes; dinoflagellates occurre additionally in four; a more diverse algal assemblage with diatoms and cryptophytes is found in lakes with moderately acidic (pH 5.7–7.0) or alkaline conditions (pH 7.0–9.4). The lake chemistry is the main determinant for the planktonic composition of the water bodies whereas the trophic state mainly determines the level of algal biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017010229136
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  • 2
    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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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Spring phytoplankton dynamics in a shallow eutrophic lake (1999)
    Springer
    Hydrobiologia 408-409 (1999), S. 269-276 
    Details
    ISSN: 1573-5117
    Keywords: shallow eutrophic lakes ; phytoplankton ; spring bloom ; carrying capacity ; primary production ; loss processes ; flushing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to other eutrophic shallow lakes in the Scharmützelsee region, a delayed onset of the phytoplankton succession in Lake Melangsee during spring was regularly observed. Biomasses were opposed to the carrying capacity of the lake (calculated from total-P, total-N and underwater light), indicating further regulating factors in spring. This phase was characterised by high Secchi depths, rising flushing and enhanced oxygen concentrations at the lake bottom. Although silicate concentrations decreased in spring, a typical pelagic diatom or cyanobacterial bloom did not develop. Therefore, we frame the hypothesis that a combination of abiotic factors such as increased losses in spring due to higher flushing and a better light supply suppresses pelagic growth and favours benthic diatoms, which outcompete pelagic diatoms for silicate. The vertical oxygen distribution in this period indicates a shift from pelagic primary production to benthic growth. Considering primary production, flushing, under water light supply and nutrients we tried to find the reasons for the depression of phytoplankton growth during spring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017096210578
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  • 5
    Electronic Resource
    Electronic Resource
    Dynamics of planktonic food webs in three mining lakes across a pH gradient (pH 2–4) (2000)
    Springer
    Hydrobiologia 433 (2000), S. 3-14 
    Details
    ISSN: 1573-5117
    Keywords: geogenic acidic lakes ; pH ; food web ; phytoplankton ; zooplankton ; corixids ; seasonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acidic mining lakes (ML) in Lusatia (Germany) are characterised by their geogenically determined chemistry. The present study describes the structure, main components and relationships within the food webs of three acidic mining lakes with different pH values (ML 111: pH 2.6; ML 117: pH 2.8; ML Felix: pH 3.6) in order to show their typical characteristics. The investigation covered the period 1995–1997. The number of species and the biomass are both low, but increase with increasing pH. Planktonic components in the most acidic ML 111 (pH 2.6–2.9) comprise bacteria, Ochromonas spp. and Chlamydomonas spp. and a few rotifers (E. worallii, C. hoodi). Heliozoans are the top-predators. In ML 117 (pH 2.8–3) Gymnodinium sp., ciliates, the rotifer B. sericus and the pioneer crustacean Chydorus sphaericus join the pelagial community. Heliozoans were not found in ML 117 or ML Felix (pH 3.4–3.8). ML Felix had the most taxa. The benthic food chain of all three lakes includes phytobenthic algae as producers, chironomids as primary consumers and corixids as top predators in the profundal. Corixids predate on small cladocerans inhabiting the pelagial in lakes with a pH above 2.8 such as ML Felix. They invade the pelagial and act as a connecting link between the benthic and the pelagic food chains, which are isolated in lakes with a lower pH. Occasionally primary producers and consumers were abundant in all three lakes. These organisms do not depend on the degree of acidity, but on the availability of essential ressources. Mass variations covered up any seasonal variation in the extremely acidic ML 111 (0.9 mm3 l−1), while in the other two lakes seasonal patterns of biomass were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004060732467
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  • 6
    Electronic Resource
    Electronic Resource
    Phytoplankton of the extremely acidic mining lakes of Lusatia (Germany) with pH ≤3 (2000)
    Springer
    Hydrobiologia 433 (2000), S. 123-128 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton ; acidic mining lakes ; autecology ; nanoflagellates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most of the flooded, open-cast lignite mining lakes of Lusatia (Germany) impacted by the oxidation of iron sulphides (pyrite and marcasite) are extremely acidic. Of 32 lakes regularly studied from 1995 to 1998, 14 have a pH 〈3 (median pH 2.3–2.9). These lakes are typically buffered by high concentrations of Fe (III) and have high conductivity (1000–5000 μS cm−1). Concentrations of dissolved inorganic carbon (DIC) and phosphorus are typically extremely low. These factors result in a very different environment for algae than found in neutral and acid-rain impacted lakes. The planktonic algal flora is generally dominated by flagellates belonging to genera of Chlorophyta (Chlamydomonas), Heterokontophyta of the class Chrysophyceae (Ochromonas, Chromulina), Cryptophyta (Cyathomonas) and Euglenophyta (Lepocinclis, Euglena mutabilis). Near-spherical non-motile Chlorophyta (Nanochlorum sp.), Heterokontophyta of the class Bacillariophyceae (Eunotia exigua, Nitzschia), Dinophyta (Gymnodinium, Peridinium umbonatum), other Chlorophyta (Scourfieldia cordiformis) and Cryptophyta (Rhodomonas minuta) are also found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004018722898
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  • 7
    Electronic Resource
    Electronic Resource
    Lake Plessa 107 (Lusatia, Germany) – an extremely acidic shallow mining lake (1999)
    Springer
    Hydrobiologia 408-409 (1999), S. 293-299 
    Details
    ISSN: 1573-5117
    Keywords: mining lake ; acidification ; plankton ; phytobenthos ; macroinvertebrates ; food-web
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Plessa 107 is an example of the older, relatively small and often shallow mining lakes of Lusatia which only have groundwater inflow. From a morphological point of view, the lake should be polymictic with short stratified periods. But besides temperature, mixing is also determined by chemical gradients in the water column that can lead up to monomixis. The lake water shows an extreme acidification with high concentrations of calcium, iron, aluminium, manganese and sulphate. Despite low TIC and TP concentrations allowing only a low primary production in the pelagial within the oligotrophic range, anoxic conditions can occur during stratification because of Fe(II) oxidation and anoxic groundwater inflow. The phytoplankton is dominated by phytoflagellates. Chlorophyll concentrations follow a yearly pattern determined by temperature and light availability. The zooplankton consists of two rotifer species, ciliates and heliozoans. Sediment analyses show contrary depth gradients of Fe and P with a very high fraction of Fe in the upper sediment layers (up to 60% of DW) which decreases with depth. Probably due to groundwater inflow, at some sites substantial decreases in redox potential and conductivity can be observed with increasing sediment depth accompanied by increases of pH, DOC, DIC and DIP concentrations. No correlations have been found between the available phosphorus or carbon concentrations in the sediment porewater and the phytobenthic biomass. Euglena mutabilis(Euglenophyceae) and Pinnularia acoricola(Bacillariophyceae) are the dominant phytobenthic species. Lake Plessa 107 has a benthic food-web that consists of benthic algae, chironomids and corixids and a pelagic food-web which is composed of phytoflagellates, rotifers, ciliates and heliozoans. The two food-webs are not coupled because larger prey organisms such as crustaceans are missing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017038616513
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