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Reproduction of Potamothrix hammoniensis (Oligochaeta) in shallow eutrophic lakes

Żbikowski J., Mimier D., Żbikowska E.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 2

181--189

EN

The aim of the study was to indicate the abiotic parameters of water and bottom sediments, which significantly affect the reproduction of Potamothrix hammoniensis in 9 shallow eutrophic lakes, of which 5 were dominated by macrophytes and 4 – by phytoplankton. Samples were collected once a month from January to December 2012. The percentage of Potamothrix hammoniensis individuals with a developed reproductive system varied in individual lakes and ranged from 14 to 72%. There was no correlation between the distinguished lake types and the proportion of sexually mature individuals. The reproductive activity was not observed in summer and early autumn. Among the measured parameters, the highest values of the Pearson correlation coefficient were found between the percentage of individuals with a developed reproductive system and the conductivity (r = 0.69; p < 0.001), pH (r = 0.51; p = 0.002) and the organic matter content in the sediments (r = −0.42; p = 0.012). It is worth noting that there was no correlation between the percentage of sexually mature specimens and the water temperature (r = −0.22, p = 0.204) and the oxygen concentration (r = −0.08; p = 0.648).

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Peculiarities of macrozoobenthos in the offshore zone of a small artificial post-gravel pit reservoir

Żbikowski J., Kobak J.

Oceanological and Hydrobiological Studies

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2010

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Vol. 39, No.1

39-59

EN

The offshore macrozoobenthos and selected environmental parameters were studied in a small artificial reservoir, created through sand and gravel extraction. The results are rather surprising. Despite the shallow depth and good wind exposure of the reservoir, a thermal and oxygen stratification developed in the summer, causing hypoxic conditions near the bottom, even though the organic matter content in the sediments was <5%. Furthermore, despite the high fish abundance, chaoborids prevailed in zoobenthos, while Tanytarsus sp. and Chironomus sp. co-dominated among chironomids. This study attempts to explain the observed phenomena, though the presented hypotheses still need further confirmation.

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Long-term changes and spatial variability of mollusc communsities in selected habitats within the dam reservoir (Włocławek Reservoir, Vistula River, Central Poland)

Jurkiewicz-Karnkowska E., Żbikowski J.

Polish Journal of Ecology

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2004

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Vol. 52, nr 4

491-503

EN

The studies on long-term and spatial variability in dominance pattern and abundance of malacofauna in selected habitats of the Włocławek Reservoir (Central Poland) were made in relation to environmental factors. Abundant and relatively rich in species malacocenoses were dominated by Sphaerium corneum. Malacofauna of shallow biotopes was characterized by higher species richness and lower abundance than molluscs inhabiting the old river bed. Eutrophication, turbidity and transformation of bottom sediments are likely to be the most important factors influencing changes in malacocenoses.