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  • Articles  (32)
  • phytoplankton  (15)
  • saline lakes  (12)
  • Romania  (10)
  • Springer  (32)
  • 1995-1999  (32)
  • Geography  (32)
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  • Springer  (32)
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  • 1
    ISSN: 1573-8590
    Keywords: British Columbia ; chrysophytes ; paleolimnology ; saline lakes ; stomatocysts ; weighted-averaging model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Chrysophycean stomatocysts were identified and enumerated from the surface sediments of 60 lakes located on the Interior Plateau of British Columbia. The lakes span a salinity gradient from freshwater to hypersaline (0.0–92.4 g L−1), with the majority being fresh to hyposaline. One hundred and ten stomatocyst morphotypes, almost all of which were previously described, were identified from the lake sediments. The first axis of direct gradient analysis, which was highly significant, was essentially a salinity axis (i.e. [Ca], [Mg], [K], [Na], [SO4], [DIC], and [Cl]). Most cysts were found to have fairly broad tolerances, with the narrowest tolerances occurring among morphotypes with the lowest salinity optima. Weighted-averaging regression and calibration techniques were used to develop an inference model to measure the relationship between measured average lakewater salinity and stomatocyst inferred salinity (apparent r2=0.80). Simple weighted-averaging produced a model with a lower bootstrapped RMSE of prediction than weighted-averaging with tolerance downweighting. These data indicate that chrysophyte stomatocysts are useful quantitative indicators of past lakewater salinity (in the freshwater to hyposaline range) in B.C. lakes, and can be used to strengthen the interpretations from diatom-inference models already developed from the same region.
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  • 2
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    International journal of salt lake research 6 (1997), S. 55-66 
    ISSN: 1573-8590
    Keywords: evaporites ; Romania ; solution lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The distribution of solution lakes on gypsum evaporites isconsidered. Details are given of Lake Inva^rtita (Nucs¸oara), aRomanian lake of this type, in the Arges¸ district.
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  • 3
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    International journal of salt lake research 6 (1997), S. 55-66 
    ISSN: 1573-8590
    Keywords: evaporites ; Romania ; solution lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The distribution of solution lakes on gypsum evaporites is considered. Details are given of Lake Invârtita (Nuc§oara), a Romanian lake of this type, in the Arge§ district.
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  • 4
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    International journal of salt lake research 6 (1997), S. 217-231 
    ISSN: 1573-8590
    Keywords: saline water-bodies ; phytoplankton ; biomass ; production ; chlorophyll ; P/B ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Phytoplankton and its production in water-bodies of the lower Amu Dar'yawere investigated in 1984–1989. The structure and functional nature ofthe phytoplankton in the water-bodies studied were analogous to those ofthe littoral zone of eutrophic lakes, considering hydrological andhydrochemical conditions. The very high average annual P/B ratios(453–582) are considered as regional features, namely high lightintensity and prolonged light period, the salinity usual for salinewaters under anthropogenic influence, the frequent and discrete incomeof nutrients in drainage water and from sediments.
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  • 5
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    International journal of salt lake research 6 (1997), S. 353-371 
    ISSN: 1573-8590
    Keywords: hypersaline lakes ; multivariate methods ; phytoplankton ; seasonality ; shallow lakes ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Honda saline lake is located in an endorheic basin in the south of Spain. The lake is very shallow, with frequent seasonal drought and a high degree of unpredictability. It was sampled monthly during a relatively dry year (1994–1995, 5 months permanence). To establish a relationship between environmental variables (temperature, depth, salinity and conductivity), variables related to biological activity (organic matter, total solids suspension, and pH) and the planktonic community in the sampled months, various uni- and multivariate statistical methods were carried out. Dunaliella salina, D. viridis, and ciliates sp. 2 is the principal species group used to average out the dissimilarity between the samples. Multivariate analysis showed that salinity (as TDS), conductivity and pH made major and significant contributions to the explanation of the variance in the sample data.
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  • 6
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    International journal of salt lake research 6 (1997), S. 353-371 
    ISSN: 1573-8590
    Keywords: hypersaline lakes ; multivariate methods ; phytoplankton ; seasonality ; shallow lakes ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Honda saline lake is located in an endorheic basin in the south of Spain. The lake is very shallow, with frequent seasonal drought and a high degree of unpredictability. It was sampled monthly during a relatively dry year (1994–1995, 5 months permanence). To establish a relationship between environmental variables (temperature, depth, salinity and conductivity), variables related to biological activity (organic matter, total solids suspension, and pH) and the planktonic community in the sampled months, various uni-and miltivariate statistical methods were carried out.Dunaliella salina, D. viridis, and ciliates sp. 2 is the principal species group used to average out the dissimilarity between the samples. Muttivariate analysis showed that salinity (as TDS), conductivity and pH made major and significant contributions to the explanation of the variance in the sample data.
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  • 7
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    International journal of salt lake research 7 (1998), S. 13-24 
    ISSN: 1573-8590
    Keywords: Artemia ; bacteria ; benthic microbial communities ; ecology ; feeding biology ; grazing ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Primary production in Lake Hayward, Western Australia, is dominated by benthic microbial communities, with limited planktonic primary production. This study investigated the question of how Artemia, commonly regarded as simple, obligate, non-selective filter feeders, were able to survive in this system. Bacteria (heterotrophic and autotrophic, filamentous and unicellular) were the major components in the diet of the Artemia in Lake Hayward. These bacteria were derived from bacterial aggregates in the water column and also from benthic mat material (both still attached to the substrate and from pieces floating in the water column). Benthic diatoms were a substantial dietary component of animals living in the unstratified shallow regions. Photosynthetic eukaryotic nanoplankton comprised a minor component of the diet of this Artemia population. Gut contents of a large number of animals and the results of a simple laboratory test indicated that these animals utilise substrate-bound food resources. The results of the present study raises the question of the ecological significance of surface grazing by brine shrimps in other shallow, benthos dominated saline systems.
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  • 8
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    International journal of salt lake research 7 (1998), S. 87-108 
    ISSN: 1573-8590
    Keywords: benthos ; crater lakes ; littoral ; macroinvertebrates ; Mexico ; Puebla ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Two saline crater lakes in the basin of Oriental, Puebla-Tlaxcala-Veracruz, were investigated for littoral benthic macroinvertebrates. Fifty taxa were identified with the oligochaetes, amphipods, chironomids and leeches the dominant organisms. These four taxa made up to 99 per cent in both number and biomass. Limnodrilus hoffmeisteri, Hyalella azteca, Tanypus (Apelopia) sp. and Stictochironomus sp. were the most abundant organisms. Unlike other saline lakes which have a littoral benthos dominated by chironomids, Alchichica and Atexcac were dominated by oligochaetes (70–73 per cent). The gastropod, Physa sp., was found up to a salinity of 8 g L-1; in other studies, it has been found in lower salinities. L. hoffmeisteri is also a typical inhabitant of freshwater lakes, particularly of deep waters. It was dominant in the shallow, saline waters of the two lakes studied. Salinity did not affect species richness. Alchichica, the most saline of the six crater lakes of Puebla (salinity, 7.4 g L-1), had 30 per cent more species than the freshwater lakes, and double the species number of Atexcac. It seems the main factor controlling species richness and the density and biomass of organisms in Alchichica and Atexcac is the presence of aquatic vegetation. It does this by increasing habitat heterogeneity and providing food and protection against predators.
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  • 9
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    International journal of salt lake research 7 (1998), S. 87-108 
    ISSN: 1573-8590
    Keywords: benthos ; crater lakes ; littoral ; macroinvertebrates ; Mexico ; Puebla ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Two saline crater lakes in the basin of Oriental, Puebla-Tlaxcala-Veracruz, were investigated for littoral benthic macroinvertebrates. Fifty taxa were identified with the oligochaetes, amphipods, chironomids and leeches the dominant organisms. These four taxa made up to 99 per cent in both number and biomass.Limnodrilus hoffmeisteri, Hyalella azteca, Tanypus (Apelopia) sp. andStictochironomus sp. were the most abundant organisms. Unlike other saline lakes which have a littoral benthos dominated by chironomids, Alchichica and Atexcac were dominated by oligochaetes (70–73 per cent). The gastropod,Physa sp., was found up to a salinity of 8 g L−1; in other studies, it has been found in lower salinities.L. hoffmeisteri is also a typical inhabitant of freshwater lakes, particularly of deep waters. It was dominant in the shallow, saline waters of the two lakes studied. Salinity did not affect species richness. Alchichica, the most saline of the six crater lakes of Puebla (salinity, 7.4 g L−1), had 30 per cent more species than the freshwater lakes, and double the species number of Atexcac. It seems the main factor controlling species richness and the density and biomass of organisms in Alchichica and Atexcac is the presence of aquatic vegetation. It does this by increasing habitat heterogeneity and providing food and protection against predators.
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  • 10
    ISSN: 1573-8590
    Keywords: microbial mats ; mixis ; nutrient loading ; periphyton ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The changes in the trophic state in the Salada de Chiprana (north-eastern Spain) over two quite different seasonal cycles (1989, 1994/95) were studied. During the former cycle, the lake was permanently stratified, and was biogenically meromictic, and in the latter, showed no apparent stratification. The main variables related to the physico-chemical changes observed can be attributed to the effect caused by the increase in the nutrient loading. The large amounts of nutrients (total-N and total-P) and organic matter are due to the use of the lake as a reservoir for water discharged from irrigation. Two remarkable effects of the change are the permanent mixing of the water column and the immobilization of phosphorus in the form of ionic species and solid phases that are not available to the biota especially primary producers (phytoplankton, periphyton, microbial mats). The results of the present study emphasize the fragility of (hyper) saline ecosystems to anthropogenic disturbances such as increases in freshwater inflow and nutrient inputs. Likewise, the study reveals the failure of conservation criteria that have been used to manage this lake, especially those which refer to the control of freshwater, nutrient-rich influents.
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  • 11
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    International journal of salt lake research 7 (1998), S. 261-274 
    ISSN: 1573-8590
    Keywords: cyanobacteria ; lake management ; Mono Lake ; nitrogen fixation ; salinity ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Mono Lake is a hypersaline alkaline lake in the high altitude Great Basin desert of eastern California. Algal productivity of the lake is nitrogen-limited, and a contributing source is derived from benthic nitrogen fixation. Lake level and salinity have fluctuated with natural climatic variations but have also been affected by the diversion of tributary streams. This research examines the influence of varied salinity and lake level on the potential for benthic nitrogen fixation in Mono Lake. A sediment-surface microbial mat community was exposed directly, and in acclimated cultures, to a range of Mono Lake salinities under anaerobic incubations and the activity of nitrogenase assayed by acetylene reduction. Activity was stimulated in light, but also occurred in darkness. Over an experimental salinity range from 50 to 150 g L−1 TDS, nitrogenase activity was reduced by 90 per cent, with the activity persisting at the highest salinity being attributable to dark fixation alone. Between a salinity of 50 g L−1, occurring in Mono Lake over 50 years ago, and 100 g L−1, nitrogenase activity was reduced by nearly half. Changes in the area of the littoral zone at varied lake levels also affect the total amount of potential benthic nitrogen fixation in the lake. An accounting of yearly inputs of nitrogen to Mono Lake suggests N2-fixation could contribute as much as 76–81 percent of the total. Inhibition of nitrogen fixation rates by increased salinity could limit the long-term nutrient supply and benthic primary productivity of this ecosystem.
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  • 12
    ISSN: 1573-8590
    Keywords: conductivity ; relative abundance ; saline lakes ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Zooplankton collected from vertical net tows were related to the environmental variables from 98 lakes from the Interior Plateau of British Columbia. Canonical correspondence analysis showed that both salinity and ionic composition (pH and Mg) of the lake-water made major and significant contributions to the first two ordination axes (λ=0.42 and 0.11 respectively,P〈0.05). BothArtemia franciscana andMoina hutchinsoni had their highest relative abundance in meso-hypersaline waters. However,Artemia franciscana preferred waters that were higher in Mg and Ca, whileMoina hutchinsoni was found in waters that were lower in Mg and Ca. Similarly, at intermediate salinities,Daphnia pulex and the calanoid copepods preferred waters slightly lower in Mg and Ca, whereasCeriodaphnia laticaudata andSimocephalus spp. were relatively more common in waters higher in Mg and Ca. Because the freshest lakes studied varied much less in ionic composition, the zooplankton in these lakes did not show a preference to ionic composition. As expected, multi-generic groups, such as the calanoid copepods, cyclopoid copepods and nauplii, had wider tolerances to conductivity than groups identified to lower taxonomic levels. Significant weighted-averaging regression and calibration models of conductivity were developed based on zooplankton species composition from the study lakes (r 2=0.56,P〈0.05). Samples composed largely of multi-generic taxa yielded the worst estimates of salinity in the reconstruction model. This study suggests that zooplankton community composition may be developed into a useful proxy for paleosalinity reconstruction.
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  • 13
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    International journal of salt lake research 6 (1997), S. 5-16 
    ISSN: 1573-8590
    Keywords: Aral Sea ; Central Asia ; EC (electrical conductivity) ; Lake Balkhash ; Lake Kamyslybas ; phytoplankton ; saline lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The Aral Sea, Lake Balkhash, and Lake Kamyslybas are closed lakes inCentral Asia. They range from oligosaline to metasaline. The salinity of theAral Sea has increased by more than 30 g L−1 sincewidespread irrigation began in its catchment area. Few studies of thephytoplankton have been conducted on these lakes since extensive irrigationstarted. The investigation reported here compares the flora of phytoplanktonin these saline lakes. In the Small Aral Sea, phytoplankton densitygradually decreased with increasing electrical conductivity (EC) (∼salinity), but there was no such relation in Lake Balkhash and LakeKamyslybas. In the Aral Sea, Dinophyceae and Bacillariophyceae werefrequently observed in most areas of high EC value, and Cyanophyceae weremost conspicuous in the area of medium and lower EC values. In LakeBalkhash, Cyanophyceae were most conspicuous, but Chlorophyceae were alsonoticeable. Most Cyanophyceae in Aral Sea formed filaments with heterocysts.The distinct characteristic of the phytoplankton of the Lake Balkhash wasthat all dominant species form colonies covered with a gelatinous film.Siliceousplankton diversity gradually decreased with increasing EC values inthe Aral Sea and Lake Balkhash.
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  • 14
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    International journal of salt lake research 6 (1997), S. 217-231 
    ISSN: 1573-8590
    Keywords: saline water-bodies ; phytoplankton ; biomass ; production ; chlorophyll ; P/B ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Phytoplankton and its production in water-bodies of the lower Amu Dar'ya were investigated in 1984–1989. The structure and functional nature of the phytoplankton in the water-bodies studied were analogous to those of the littoral zone of eutrophic lakes, considering hydrological and hydrochemical conditions. The very high average annual P/B ratios (453–582) are considered as regional features, namely high light intensity and prolonged light period, the salinity usual for saline waters under anthropogenic influence, the frequent and discrete income of nutrients in drainage water and from sediments.
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  • 15
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    International journal of salt lake research 7 (1998), S. 261-274 
    ISSN: 1573-8590
    Keywords: cyanobacteria ; lake management ; Mono Lake〉/kwd〉 ; nitrogen fixation ; salinity ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Mono Lake is a hypersaline alkaline lake in the high altitude Great Basin desert of eastern California. Algal productivity of the lake is nitrogen-limited, and a contributing source is derived from benthic nitrogen fixation. Lake level and salinity have fluctuated with natural climatic variations but have also been affected by the diversion of tributary streams. This research examines the influence of varied salinity and lake level on the potential for benthic nitrogen fixation in Mono Lake. A sediment-surface microbial mat community was exposed directly, and in acclimated cultures, to a range of Mono Lake salinities under anaerobic incubations and the activity of nitrogenase assayed by acetylene reduction. Activity was stimulated in light, but also occurred in darkness. Over an experimental salinity range from 50 to 150 g L-1 TDS, nitrogenase activity was reduced by 90 per crnt, with the activity persisting at the highest salinity being attributable to dark fixation alone. Between a salinity of 50 g L-1, occurring in Mono Lake over 50 years ago, and 100 g L-1, nitrogenase activity was reduced by nearly half. Changes in the area of the littoral zone at varied lake levels also affect the total amount of potential benthic nitrogen fixation in the lake. An accounting of yearly inputs of nitrogen to Mono Lake suggests N2-fixation could contribute as much as 76–81 percent of the total. Inhibition of nitrogen fixation rates by increased salinity could limit the long-term nutrient supply and benthic primary productivity of this ecosystem.
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  • 16
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    International journal of salt lake research 8 (1999), S. 7-18 
    ISSN: 1573-8590
    Keywords: coastal waters ; production ; decomposition ; phytoplankton ; Aral Sea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The species composition, population density, biomass and main functional characteristics of the phytoplankton community near Cape Tastubec, northern Aral Sea in September 1993 were investigated. The characteristics investigated were daily primary production, decomposition, and photosynthetic intensity. The data indicate that certain changes in the structure and function of the phytoplankton have recently taken place.
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  • 17
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    International journal of salt lake research 8 (1999), S. 7-18 
    ISSN: 1573-8590
    Keywords: coastal waters ; production ; decomposition ; phytoplankton ; Aral Sea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The species composition, population density, biomass and main functional characteristics of the phytoplankton community near Cape Tastubec, northern Aral Sea in September 1993 were investigated. The characteristics investigated were daily primary production, decomposition, and photosynthetic intensity. The data indicate that certain changes in the structure and function of the phytoplankton have recently taken place.
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  • 18
    ISSN: 1573-8590
    Keywords: bacterioplankton ; blue-green algae ; meromictic salt lake ; phytoplankton ; vertical structure ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The specific composition, vertical distribution and daily migration of plankton in a meromictic salt lake, Lake Shira, have been investigated. The main structural components of the ecosystem are bacteria, algae and crustaceans. Since the late 1970s, blue-green algae are reported as dominant. Nowadays the phytoplankton is dominated by Lyngbya contorta, Microcystis ichtyoblabe (Cyanophyta), Cyclotella tuberculata (Bacillariophyta) and Dictyosphaerium tetrachotomum (Chlorophyta). The zooplankton of Lake Shira comprises Arctodiaptomus salinus (Copepoda), Brachionus plicatilis and Hexarthra oxiuris (Rotatoria). Investigation revealed a stratified vertical distribution of all dominant species except Cyclotella with a maximum at a depth of 12--15 m during the summer growth period. Zooplanktons differ in the pattern of distribution and daily migration, but most zooplankton tend to concentrate near the surface. The possible reasons for the vertical distribution of the plankton are discussed.
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  • 19
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    International journal of salt lake research 5 (1996), S. 287-313 
    ISSN: 1573-8590
    Keywords: claypans ; hydrology ; intermittent wetlands ; littoral invertebrates ; physicochemical features ; saline lakes ; tadpoles ; waterbirds ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Bloodwood Station, 130 km NW of Bourke, NSW, has a diverse array of intermittently flooded wetlands raging from salinas to fresh waters, either clear, opaque or very turbid, and from relatively large (820 ha) to quite small (〈1 ha). A study during 1995 followed the filling of 22 wetlands after heavy rain in January to subsequent drying or recession, and looked at the relationship between physicochemical features, aquatic plants, zooplankton, littoral invertebrates, tadpoles, and waterbirds. Wetlands were delineated into two major groups: saline and fresh, with the latter subdivided into five types — clear fresh waters, artificial tanks, vegetated pans, turbid pans, and miscellaneous. The saline lakes developed extensive beds of macrophytes some months after filling which attracted large number of waterbirds. Later, abundant Zooplankton were feed for many Pink-eared Duck. Most of the fresh waters developed large initial populations of phyllopodous crustaceans, Zooplankton and tadpoles, but these waters attracted few waterbirds. Clearer fresh waters later grew macrophytes which attracted many waterbirds, but the turbid claypans remained unattractive to waterbirds during their existence, despite harbouring a host of invertebrates. The vegetated pans, artificial tanks and miscellaneous sites attracted only a few waterbirds, but the tanks along with the persistent clear fresh waters become important as feeding and resting sites as other wetlands dried towards the year end. Few waterbirds bred on these wetlands during 1995. However, many were important as major feeding sites and formed part of a mosaic of intermittent wetlands for Australia's inland waterbirds.
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  • 20
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    International journal of salt lake research 5 (1996), S. 253-260 
    ISSN: 1573-8590
    Keywords: saline lakes ; chlorophyll ; size-fractions ; phytoplankton ; shallow lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The size-fractionated distribution of chlorophylla was studied in a temporary hypersaline lake situated in the south of Spain during an annual hydrological cycle characterized by low levels of rainfall. The contribution of each size class to the total chlorophylla concentration indicates that ultraplankton (size class 〈5μm) was the most important fraction of phytoplankton biomass during this year.
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  • 21
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    International journal of salt lake research 6 (1997), S. 5-16 
    ISSN: 1573-8590
    Keywords: Aral Sea ; Central Asia ; EC (electrical conductivity) ; Lake Balkhash ; Lake Kamyslybas ; phytoplankton ; saline lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The Aral Sea, Lake Balkhash, and Lake Kamyslybas are closed lakes in Central Asia. They range from oligosaline to metasaline. The salinity of the Aral Sea has increased by more than 30 g L−1 since widespread irrigation began in its catchment area. Few studies of the phytoplankton have been conducted on these lakes since extensive irrigation started. The investigation reported here compares the flora of phytoplankton in these saline lakes. In the Small Aral Sea, phytoplankton density gradually decreased with increasing electrical conductivity (EC) (∼ salinity), but there was no such relation in Lake Balkhash and Lake Kamyslybas. In the Aral Sea, Dinophyceae and Bacillariophyceae were frequently observed in most areas of high EC value, and Cyanophyceae were most conspicuous in the area of medium and lower EC values. In Lake Balkhash, Cyanophyceae were most conspicuous, but Chlorophyceae were also noticeable. Most Cyanophyceae in Aral Sea formed filaments with heterocysts. The distinct characteristic of the phytoplankton of the Lake Balkhash was that all dominant species form colonies covered with a gelatinous film. Siliceousplankton diversity gradually decreased with increasing EC values in the Aral Sea and Lake Balkhash.
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  • 22
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    International journal of salt lake research 7 (1998), S. 45-80 
    ISSN: 1573-8590
    Keywords: aquatic flora and fauna ; circum-lacustrine vegetation ; cormophytes ; microphytobenthos ; pelogenous/non-pelogenous lakes ; phytoplankton ; Romania ; saline lakes ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract An inventory of the aquatic and circum-lacustrine flora and aquatic fauna of 23 karst- and anthroposaline lakes formed on Miocene rock salt bodies in Romania was undertaken. Simultaneous field determinations of water and sediment pH, total dissolved solids, Secchi transparency and lake maximum depth were also made. Environmental conditions for phytoplankton, microphytobenthos, macrophyte and cormophyte species were defined. Relations between the numbers of plankton, microbenthos, macrophyte and cormophyte species differentiated pelogenous (usually, therapeutic) and non-pelogenous lakes. High densities and occurrence frequencies characterized the most representative species. For three of these species, Amphora veneta, Artemia sp. and Potamogeton pectinatus, ecological conditions were noted. In the circum-lacustrine vegetation, glycophytes were more important than halophytes.
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  • 23
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    International journal of salt lake research 7 (1998), S. 13-24 
    ISSN: 1573-8590
    Keywords: Artemia ; bacteria ; benthic microbial communities ; ecology ; feeding biology ; grazing ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Primary production in Lake Hayward, Western Australia, is dominated by benthic microbial communities, with limited planktonic primary production. This study investigated the question of howArtemia, commonly regarded as simple, obligate, non-selective filter feeders, were able to survive in this system. Bacteria (heterotrophic and autotrophic, filamentous and unicellular) were the major components in the diet of theArtemia in Lake Hayward. These bacteria were derived from bacterial aggregates in the water column and also from benthic mat material (both still attached to the substrate and from pieces floating in the water column). Benthic diatoms were a substantial dietary component of animals living in the unstratified shallow regions. Photosynthetic eukaryotic nanoplankton comprised a minor component of the diet of thisArtemia population. Gut contents of a large number of animals and the results of a simple laboratory test indicated that these animals utilise substrate-bound food resources. The results of the present study raises the question of the ecological significance of surface grazing by brine shrimps in other shallow, benthos dominated saline systems.
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  • 24
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    International journal of salt lake research 7 (1998), S. 45-80 
    ISSN: 1573-8590
    Keywords: aquatic flora and fauna ; circum-lacustrine vegetation ; cormophytes ; microphytobenthos ; pelogenous/non-pelogenous lakes ; phytoplankton ; Romania ; saline lakes ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract An inventory of the aquatic and circum-lacustrine flora and aquatic fauna of 23 karst- and anthroposaline lakes formed on Miocene rock salt bodies in Romania was undertaken. Simultaneous field determinations of water and sediment pH, total dissolved solids, Secchi transparency and lake maximum depth were also made. Environmental conditions for phytoplankton, microphytobenthos, macrophyte and cormophyte species were defined. Relations between the numbers of plankton, microbenthos, macrophyte and cormophyte species differentiated pelogenous (usually, therapeutic) and non-pelogenous lakes. High densities and occurrence frequencies characterized the most representative species. For three of these species,Amphora veneta, Artemia sp. andPotamogeton pectinatus, ecological conditions were noted. In the circum-lacustrine vegetation, glycophytes were more important than halophytes.
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  • 25
    ISSN: 1573-8590
    Keywords: microbial mats ; mixis ; nutrient loading ; periphyton ; saline lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The changes in the trophic state in the Salada de Chiprana (north-eastern Spain) over two quite different seasonal cycles (1989, 1994/95) were studied. During the former cycle, the lake was permanently stratified, and was biogenically meromictic, and in the latter, showed no apparent stratification. The main variables related to the physico-chemical changes observed can be attributed to the effect caused by the increase in the nutrient loading. The large amounts of nutrients (total-N and total-P) and organic matter are due to the use of the lake as a reservoir for water discharged from irrigation. Two remarkable effects of the change are the permanent mixing of the water column and the immobilization of phosphorus in the form of ionic species and solid phases that are not available to the biota especially primary producers (phytoplankton, periphyton, microbial mats). The results of the present study emphasize the fragility of (hyper) saline ecosystems to anthropogenic disturbances such as increases in freshwater inflow and nutrient inputs. Likewise, the study reveals the failure of conservation criteria that have been used to manage this lake, especially those which refer to the control of freshwater, nutrient-rich influents.
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  • 26
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    International journal of salt lake research 8 (1999), S. 211-232 
    ISSN: 1573-8590
    Keywords: bacterioplankton ; blue-green algae ; meromictic salt lake ; phytoplankton ; vertical structure ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The specific composition, vertical distribution and daily migration of plankton in a meromictic salt lake, Lake Shira, have been investigated. The main structural components of the ecosystem are bacteria, algae and crustaceans. Since the late 1970s, blue-green algae are reported as dominant. Nowadays the phytoplankton is dominated byLyngbya contorta, Microcystis ichtyoblabe (Cyanophyta),Cyclotella tuberculata (Bacillariophyta) andDictyosphaerium tetrachotomum (Chlorophyta). The zooplankton of Lake Shira comprisesArctodiaptomus salinus (Copepoda),Brachionus plicatilis andHexarthra oxiuris (Rotatoria). Investigation revealed a stratified vertical distribution of all dominant species exceptCyclotella with a maximum at a depth of 12–15 m during the summer growth period. Zooplanktons differ in the pattern of distribution and daily migration, but most zooplankton tend to concentrate near the surface. The possible reasons for the vertical distribution of the plankton are discussed.
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  • 27
    ISSN: 1572-9893
    Keywords: transition period ; rural space ; rural development ; pluriactivity ; survival strategies ; Romania
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract This paper presents some initial implications of the changes brought about by recent economic transformations within the Romanian rural sector during the current transition period. As a case study of those trends, within the context of pluriactivity and constraints to rural development, it looks at some characteristics of agricultural production in the Subcarpathian region of the county of Valcea, an area where collectivisation, and thus its influences, had been partial and limited. The paper links micro and macro view points. At the micro level, it looks at the coping strategies, based on pluriactivity, adopted by rural households under changing economic conditions. At the macro level, the paper discusses some of the possible factors supporting as well as hindering rural welfare levels and agricultural development under current economic conditions.
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  • 28
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    GeoJournal 44 (1998), S. 151-160 
    ISSN: 1572-9893
    Keywords: health ; Romania ; transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract The paper attempts to make an assessment of the health state of the Romanian population during the transition period; the evolution of the health indicators, analyzed in the European context, shows the precarious health state of the Romanian population, in comparison both to Western countries and to the countries which are crossing a transition phase themselves. The values of the health indicators by region also show inequalities of health, the north-western and south-eastern areas of the country having to face serious problems. The reduction of living standard, the low quality health services, together with other factors associated with lifestyle seem to be responsible for the deterioration of the health state of the Romanian population. The introduction of adequate health and social policies in the following period could bring about an improvement of the situation.
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  • 29
    ISSN: 1572-9893
    Keywords: agriculture ; border region ; communities ; commuting ; conservation ; Romania ; tourism ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract A most distinctive feature of the settlement pattern of the Brasov area is the extreme dispersal of mixed farming encountered in the western extreme of the county to the north and south of Zarnesti: the Bran and Poiana Marului areas. Here a system of peasant subsistence farming developed in a political borderland between the Habsburg and Ottoman Empires. Despite feudal pressures, the peasantry took all available opportunities to extend their independence including elaborate transhumance systems. And after seeing transfrontier commerce as a source of plunder, in the tradition of Balkan highway robbery within relatively unregulated spaces, the peasantry has profited through employment in factories, particularly during the communist period. However, the current recession in manufacturing is throwing the rural population back on limited land resources. Although farming assumes an important subsistence role which contributes to stability, the long-term survival of these communities will depend on new sources of income. Rural tourism has considerable potential and a promising start has been made in Bran. There are, however, constraints on the further development of the business and great attention will have to be given to the conservation of the environment in both the Bucegi Mountains and the Piatra Craiului where national park status is proposed.
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  • 30
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    GeoJournal 46 (1998), S. 319-336 
    ISSN: 1572-9893
    Keywords: culture ; forest ; key villages ; national park ; natural park ; Romania ; rural development ; settlement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract The Apuseni Mountains, part of the Western Carpathians, are distinctive in cultural terms because of the highly dispersed settlement patterns that have developed on the high erosion surfaces where the Moti people cleared the forests to allow for an expansion of family farming in the eighteenth and nineteenth centuries. These small ‘crang’ settlements remain, but the population is declining in the face of limited employment opportunities and poor services. The question arises as to the most appropriate rural development strategy for the region, following the communist period which encouraged centralisation through the provision of housing and industry in key villages and new towns. The emphasis on private farming and the expansion of tourism could protect the inherited cultural landscape but money must be found to improve rural services. There is also a strong conservation movement which supports the establishment of a national park, but this could constrain development through controls on grazing and woodcutting. Hence the dialogue continues to find the best compromise and the concept of a ‘natural park’ is being discussed with such a reconciliation in mind.
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  • 31
    ISSN: 1572-9893
    Keywords: chamber of commerce ; economy ; experts ; institutions ; local government ; Romania ; rural ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics, drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage. Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is able to grow more rapidly and attract greater foreign investment.
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  • 32
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    GeoJournal 46 (1998), S. 289-303 
    ISSN: 1572-9893
    Keywords: conservation ; ecosystem ; National Park ; Natural Park ; pollution ; rural development ; Romania ; tourism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Valcea is one of Romania's Wallachian counties with landscapes which grade from the Carpathians through the Subcarpathians and Piedmont zone towards the plain. Agriculture plays a major role in the economy but there is also a long-established tourist industry and the industrial base (established through the processing of local raw materials: agricultural commodities, timber and salt) has been enlarged and diversified under communism. The tourist industry has also expanded with reference to the mineral waters. But agriculture still plays an important role. Environmental pressures on sensitive Carpathian ecosystems have increased over the years and under the transition conservation measures should include national park designations to provide a buffer for clusters of nature reserves. The paper discusses the nature of the environmental problems and the significance of national and ‘natural’ parks for the development of tourism in the area, with particular reference to Buila-Vanturarita area of the Capatina Mountains.
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