Because of the slow current velocity, man-made ditches may create distinct physical and ecological conditions that are suitable for the growth of zooplankton populations. However, the influence of drainage ditches on zooplankton communities has not been studied yet. This study aims to answer the following questions: i) Are man-made ditches a rich source of zooplankton? ii) What current velocity value leads to abundant zooplankton in man-made ditches? iii) Do zooplankton communities differ between man-made ditches and connected natural streams? In man-made drainage ditches with a water current lower than 0.1 m s-1, the abundance of zooplankton was greater than in the majority of streams. Sometimes this level of abundance was equivalent to the densities of zooplankton in lakes or dammed reservoirs. The presence of zooplankton in man-made ditches may be of great importance to the establishment of food webs, particularly during periods of high water levels or heavy rainfall, both of which may accelerate the water current, causing the dispersion of zooplankton along the ditches and into natural streams.
Cladoceran-based paleotemperature estimates for the Younger Dryas for ten sections of paleo-oxbow lakes, valley mires, and lacustrine sediments from central Poland are presented, and their potential usefulness to climatostratigraphy is described. Most of the changes observed in the cladoceran assemblages are responses to climate changes. The cladoceran-based temperature reconstructions reflect cold conditions during the Younger Dryas (YD) and allow a division of this period into two phases: an older colder phase, between 12,800 and 12,000 cal yrs BP, and a younger, warmer phase, between ca. 12,000 and 11,500 cal yrs BP. The geomorphological features of the study sites and local environmental forces are also taken into consideration. The cladoceran-inferred summer temperature estimates from all of the study sites correspond closely with the available climate reconstruction for the YD in central Europe.
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There are 150 meteorite craters worldwide, however, their aggregations are rarely noted. The nature reserve ‘Meteoryt Morasko’ in Poland with fishless meteorite ponds was analyzed as a unique ecosystem for biological analysis of invertebrate interactions. The aim of the study was to recognize the main environmental drivers of cladoceran and copepod community structure from among biotic (competitors and predators) and abiotic factors (i.e. oxygen and pH level) in the spring season. The abundance of small cladocerans (Alonella excisa and Chydorus sphaericus) was the highest at the end of the spring season, i.e. in June, while large species (Daphnia pulex and Simocephalus exspinosus) were most abundant in May. Both size groups of Cladocera were negatively affected by invertebrate predators (Chaoborus crystallinus and carnivorous copepods), which are known to play an important role in structuring cladoceran communities due to the fishless character of the studied ponds. No negative effect of those predators was found for Copepoda, however, nauplii density was reduced by competitors (Aedes communis larvae and ostracods). The temporary character of the examined ponds, oxygen depletion and low pH of water in the shallowest pond resulted in the abundant occurrence of cladoceran males, whose high densities are usually observed in autumn.
An investigated area is located in the middle reach of the WartaRiver valley. During drillings in the Bór site organic deposits such as detritous calcareous gyttja and calcareous detritous gyttja has been documented in a depth between 14,9 and 16,6 m. The organic deposits are covered by mineral, mostly sandy deposits. The accumulation took place in the small lake formed as an abandoned channel. Palynological analysis led to conclusion that biogenic accumulation began at the end of Wartanian and took place at least to the Eemian Interglacial optimum. Results of palynological, Cladocera and geochemical analysis inform about water level changes and increasing of trophy status of the reservoir. Presence of Mesozoic substratum very close to the palaeolake bottom influenced significantly chemical features of the organic deposits. As Eemian organic deposits are uncommon in the Warta River valley, the Bór site seems important for palaeogeographical reconstructions of the Warta River valley during Eemian Interglacial.
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The succession of Cladocera assemblages in the Eemian Sławoszewek palaeolake (Central Poland) and the inferred environmental parameters are presented. The Cladocera assemblages provide a rich and relatively complete record of the Cladocera succession of the Eemian Interglacial, and are similar to those from other Eemian sites in Poland. The species composition and the variability in frequency of specimens of Cladocera made it possible to distinguish five zones of their development, which correlate well with pollen data. The Sławoszewek palaeolake existed from the early Eemian to the late Eemian Interglacial; at the end of the middle Eemian, the lake dried up temporarily. The cladoceran assemblages show that the initial shallow, oligotrophic status of the lake was followed by an increase to eutrophic status, especially during the interglacial optimum. Based on cladoceran composition, changes in climatic conditions in the mid-pollen zone E1, the late pollen zone E5 and in pollen zone E7, were recognized. It appears that cladoceran development was due mainly to climate changes, but also to changes in the locally prevailing conditions within the water body. The high frequency of cladocerans and the presence of cladoceran taxa preferring warmer water in mid-pollen zone E1 show an increase in temperature. The appearance of cold-tolerant Cladocera species at the end of pollen zone E5, suggests unfavourable conditions, probably cooling. Changes in Cladocera patterns in pollen zone E7 show that warm conditions still obtained in this area.
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The main aim of the study was to analyze diurnal changes in the composition and dynamics of the cladoceran community among three stations located along a horizontal transect that included the central part of a Myriophyllum verticillatum bed at the perimeter of a macrophyte stand and the open water zone of neighboring vegetated stations. Typically littoral species distinctly dominated the material examined. Ceriodaphnia quadrangula significantly influenced the total crustacean community. The maximum abundance of littoral species was noted in the middle part of the plant stand while the minimum was in the open water. These species revealed a similar pattern of diurnal distribution, irrespective of the station, with the highest numbers at night and the lowest during the day and morning. A similar pattern of diurnal distribution was also observed for pelagic species that exhibited significant differences in the open water zone between the day (the lowest numbers) and night (the highest) samplings. It was suggested that the diurnal distribution of cladoceran representatives between the macrophyte bed and the open water zone of Lake Wielkowiejskie might have been influenced by young fish predation (pelagic species) and by typical adaptations of particular species to living within the heterogeneous habitat of a macrophyte stand (littoral species).
Analyses of subfossil cladocerans (Crustacea: Cladocera) and chironomids (Diptera: Chironomidae) were applied to examine water-level changes in a small and oligotrophic lake in southern Finland over the past 2000 years. Major changes in the invertebrate communities occurred ca. 400 AD onwards when the littoral cladoceran Alonella nana started to replace the planktonic Eubosmina as the dominant species and chironomids Psectrocladius sordidellus group and Zalutschia zalutschicola increased. These changes were most likely due to a decreasing water level and an enlarging proportion of the littoral area, providing suitable vegetative habitats, e.g. aquatic bryophytes (mosses), for these taxa. The lowering water level reached its minimum just before the Medieval Warm Period, ca. 800-1000 AD, after which the lake level rose again and remained high until modern times. A prominent change in the chironomid assemblages occurred during the 20th century when Ablabesmyia monilis and Chironomus anthracinus type increased, presumably due to changes in water chemistry, caused by anthropogenic load of pollutants.
Alona protzi is a rare species of Cladocera, occurring in lake littoral throughout Europe. However, little is known about this animal, and so far it has not been included in provisional lists of species found in Finland. In this short report we present our findings of Alona protzi, both recent and subfossil material, as well as one previous, unpublished finding site of the species in Finland. We found three subfossil shells of this species in the bottom sediments of two lakes. In a third lake we found intact animals, an ephippial female and a male, while sampling stony bottom of lake littoral.
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This article presents results of multidisciplinary research which has been carried out in order to determine changes in the vegetation cover as well as changes in the structure of the Karaśne lake-mire complex in the Late Glacial and Holocene. In addition, human impact on the formation of the vegetation cover and the bio- and chronostratigraphy of the Late Glacial sediments is discussed.
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Sediments of two short cores collected from two basins of Kruklin Lake were studied by means of 210Pb and Cladocera analyses. The 210Pb allowed to date sediments and was helpful to obtain changes of sedimentation rate during the last two centuries. The CRS model was applied to calculate sediments age. Sedimentation rate differed strongly (from 0.55 cm/yr to 6.25 cm/yr) not only in time, but also between each basin. An accurate chronology of sediments was the basis for tracking of palaeolimnological changes with Cladocera analysis. Cladoceran planktonic:littoral ratio reflects event of artificial drop of lake water-level in the middle of nineteenth century. However, this event was recorded only in sediments of the southern, shallower basin and we suggest, that cladoceran planktonic:littoral ratio is better representative in shallow lakes. Changes of Cladocera assemblage composition suggest also strong eutrophication of lake water during the last century.
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The main aim of the study is to analyse the response of the catchment and lake ecosystem to the lake-level change on the basis of pollen, macrofossil, cladoceran and stable isotope records obtained by a comprehensive study of sediments from a shore core from Lake Juusa (Southern Estonia). The obtained multi-proxy data indicate that there is good correspondence between lithological, macrofossil and cladoceran changes during most time in the studied period. The palaeorecords show that the development of the Lake Juusa ecosystem was triggered mainly by the fluctuations of the lake level. Discrepancies of the data for some periods are caused by the concurrent processes having specific impact on the obtained records.
Lake series from the Eemian Interglacial and Early Vistulian has been discovered at Solniki in the Białystok Upland region, north-eastern Poland. Preliminary results of interdisciplinary researches (pollen, diatom, Cladocera, isotopic and magnetic susceptibility analyses) were used to illustrate the changes of the Eemian climate. At present stage of investigations, there are found signs of two abrupt climatic oscillations - first with very humid climate took place at middle part of the regional Carpinus pollen zone (E5 R PAZ), and second with cold and dry climate at middle part of the regional Pinus zone (E7 R PAZ).
PL
W Solnikach na Wysoczyźnie Białostockiej (północno-wschodnia Polska) odkryto serię osadów jeziornych reprezentujących interglacjał eemski i wczesny vistulian. Wstępne wyniki badań interdyscyplinarnych (analiza pyłkowa, okrzemkowa i Cladocera, pomiary podatności magnetycznej osadów oraz zawartości izotopów stabilnych tlenu i węgla) wykorzystano do zilustrowania zmian klimatu podczas interglacjału eemskiego. Udokumentowano dwie gwałtowne oscylacje klimatu - pierwsza z ciepłym i bardzo wilgotnym klimatem (?opady) miała miejsce w środkowej części poziomu pyłkowego E5 Carpinus, druga z klimatem suchym i bardzo zimnym - w środkowej części poziomu E7 Pinus.
Results of stable isotope, Cladocera and pollen analyses of lacustrine sediments from Besiekierz (Central Poland) are presented. The Besiekierz palaeolake is located about 25 km north of Łódź (Central Poland) at 130 m a.s.l. The 4 m thick deposits comprise silty sands and clayey silts, overlain by calcareous gyttja and organic silts and peat. Pollen analysis documents that these deposits accumulated during the Eemian Interglacial and the Early Vistulian. Based on the results of stable isotope analyses, nine isotopic horizons (Is) were defined and characterized, and these enabled reconstruction of both climatic and hydrological changes. A positive trend in δ18O values and constant values of δ 13 suggest gradual climatic warming, while constant values of δ 18O and δ 13C indicate stable conditions and/or a fast rate of sedimentation. The fluctuation of isotopic values in the upper part of the succession probably points to a shallowing of the lake due to sedimentary infill. The subfossil cladoceran fauna in the Besiekierz succession is represented by 11 solely littoral species belonging to 3 families. Four zones of Cladocera development were distinguished. The Besiekierz palaeolake was a shallow reservoir. The initial period of its existence probably saw its greatest depth. The Cladocera species present indicate the initial oligotrophic status of the lake and its subsequent increase in trophic status.We compare the results of the isotopic, cladoceran and published palynological analyses, to distinguish and explain the phases of evolution of the lake.
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From 1969 to 2002 the distribution of cladoceran species on ten islands in the southern North Sea was investigated. A total of 50 species was found. The small water bodies in the salt marsh have to be resettled after salt water floods; Macrothrix hirsuticornis and Moina brachiata are two of the pioneer species in the brackish water bodies. Most cladoceran species were found in permanent and temporary dune waters. Some of them were caught only occasionally and in low abundance. A characteristic species of dune waters is Scapholeberis rammneri, which was detected on eight islands. A small group of cladoceran species inhabited concrete basins containing drinking water for cattle and horses. The Hammersee on Juist island, a shallow freshwater lake since a dyke had been built in 1928, was inhabited by 35 species. Within the last decade the species number decreased because of eutrophication and biotopes being filled up by sedimentation. On islands with newly dug water bodies species number increased. The two species, Macrothrix hirsuticornis and Scapholeberis rammneri, characteristic of the islands in the southern North Sea, are endangered due to changes and losses of habitats on all but one (Wangerooge) islands.
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