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Phytoseston and heterotrophic bacteria in the assessment of the waters in the Wełna and Nielba Rivers

Messyasz B., Szczuka E., Kaznowski A., Burchardt L.

Oceanological and Hydrobiological Studies

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2010

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Vol. 39, No.4

45-63

EN

The phytoseston flora and heterotrophic bacteria from the two intersecting rivers were studied during the intensive water flow (from October 2006 to May 2007). The physical and chemical measurements indicated that the water quality in the rivers regarding their purity, had slightly improved in the Nielba River and deteriorated in the Wełna River, at the sites behind the intersection zone. It was in the agreement with the studied phytoseston diatom communities (dominated by eutraphentic taxa). Phytoplankton during the winter months was dominated by Aulacoseira granulata. The importance of species from the genera Oscillatoria, Planktolyngbya, Tychonema, Planktothrix, Scenedesmus/Desmodesmus, Nitzschia and Fragilaria increased in spring and autumn. Heterotrophic bacteria occurred in considerably higher numbers in the Wełna River than in the Nielba River, with a significant decrease in the waters of the Wełna River behind the river-intersection. All analyses revealed that the waters in the Wełna River were more polluted with organic compounds than in the Nielba River locations.

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Qualitative and quantitative phytoseston changes in two different stream-order river segments over a period of twelve years (Grabia and Brodnia, central Poland)

Sumorok B., Żelazna-Wieczorek J., Kostrzewa K.

Oceanological and Hydrobiological Studies

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2009

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Vol. 38, No.1

55-63

EN

Phytoseston studies were carried out at two sites near the town of Łask in the third orderstream segment of the Grabia River and the first order-stream segment of the Brodnia River, in two study periods: 1992-1993 and 2005-2006. Water and seston were sampled twice a month. The chemical parameters of N-NO3, P-PO4 and chlorophyll a were also determined. The aim of the studies was to determine the changes in the nutrient load of these ecosystems in the rivers studied over the course of 12 years and their influence on quantitative and qualitative phytoseston differentiation. No important differences in the taxonomic composition of the phytoseston between the two rivers were observed. A high participation of diatoms (over 50%), in relation to other algal groups, was recorded in both rivers. Vegetation in the Brodnia River begins to develop one month earlier than in the Grabia River. The greatest changes in the seasonal rate of algal succession occurred in the spring and summer periods, while no considerable changes in seston composition were recorded in the fall or winter periods. A decrease in phytoseston quantity was observed in the second study period. Chlorophyll a content was significantly lower in 2005-2006 than that in 1992-1993.

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Spatial distribution of chlorococcalean genera in the phytoseston of the Wełna and Nielba rivers

Messyasz B.

Oceanological and Hydrobiological Studies

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2003

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Vol. 32, No. 2

33-43

EN

The chlorococcalean flora from two crossed rivers during the summer period (from July to September 2001 and 2002) was examined. Phytoseston communities were collected from the Wełna and Nielba rivers before and behind the cross-rivers as well as from the central place of the cross-rivers. Species belonging to 6 dominant genera: Scenedesmus, Pediastrum, Monoraphidium, Ankistrodesmus, Coelastrum and Tetraedron were found in both rivers. At most of the stations located along the Wełna and Nielba rivers after their crossing a trend of increasing green algae species richness together with an increase in the total species number of cells was observed. Furthermore, it was found that the Wełna river takes over some of the Nielba phytoseston species.