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Qualitative and quantitative changes of diatoms with relation to physiochemical water parameters in the littoral zone of the urban Lake Jeziorak Mały

Zębek E.

Oceanological and Hydrobiological Studies

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2007

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Vol. 36, No.4

3-22

EN

Phytoplankton in the littoral zone of the urban Lake Jeziorak Maly (Mazurian Lakeland) were studied between April and October of 2002 and 2003. Five diatom species (Fragilaria delicalissima, Aulacoseira gramilata, Fragilaria capucina, Diatoma vulgaris, Fragilaria crotonensis) and one genus (Rlrizosolenia sp.), comprising the major proportion of total abundance and biomass of diatoms, were chosen for the study. The relationships between the biomass of these diatoms and water temperature, oxygen content, electrolytic conductivity, orthophosphates, silicon and calcium concentrations were analyzed. The biomass of species F. delicatissima, A. granulata and F. capucina tended to be the highest of the six, which were also associated with the widest temperature range, 10.0°C to 18.7°C. These three species exhibited maximum biomass at the highest orthophosphate concentrations. By contrast, F. crotonensis developed in the narrowest water temperature range, 10.0°C to 13.7°C. The maximum biomass of this species was noted at high silicon and calcium concentrations. The diatoms (except i7, capucina and RSiizosolenia sp.) contributed to statistically significant observed reductions in nutrient concentrations during their growth. These results indicate that a range of factors is involved in the productivity and limitation of the studied diatoms, with water temperature being of particular importance.

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Quantitative changes of Planktolyngbya brevicellularis, Limnothrix redekei and Aphanizomenon gracile in the annual cycle vs. physicochemical water parameters in the urban Lake Jeziorak Mały

Zębek E.

Oceanological and Hydrobiological Studies

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2006

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Vol. 35, No.1

69-84

EN

The study was conducted on net phytoplankton in the urban Lake Jeziorak Mały (Mazurian Lakeland) in the littoral zone in the years 1998 – 2003. The blue-green algae community was dominated by three species: Planktolyngbya brevicellularis (Cronberg &Komarek), Limnothrix redekei (Van Goor) Meffert and Aphanizomenon gracile Lemm. Changes in the numbers of blue-green algae were analyzed in the annual cycle, with respect to water temperature and orthophosphate concentration. One abundance peak of Planktolyngbya brevicellularis was recorded in July, of Limnothrix redekei in May, and for Aphanizomenon gracile there were two peaks in numbers in May and in August. The relationship between water temperature and the occurrence of blue-greens was statistically significant, whereas in the case of orthophosphate concentration, the coefficient of correlation was statistically significant only for Planktolyngbya brevicellularis. On the basis of equations of multiple regression the proportion of orthophosphate concentration was affirmed to be higher than water temperature. This may suggest that the blue-green species contributed to reducing the phosphorus content of the water, and the largest part in this phenomenon could be played by Planktolyngbya brevicellularis, which developed in the widest temperature range and in this way was a competitor species for remaining species.

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Qualitative and quantitative changes of blue-green algae in response to physicochemical water parameters in the urban Lake Jeziorak Mały

Zębek E.

Oceanological and Hydrobiological Studies

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2005

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Vol. 34, No.1

39--56

EN

The study was conducted on net phytoplankton in the urban Lake Jeziorak Mały (Masurian Lakeland) in 1998. The blue-green algae community was dominated by the species - Planktolyngbya brevicellularis, Limnothrix redekei, and Aphanizomenon gracile. The relationships between selected physicochemical water parameters and the numbers of blue-green algae were analyzed. The correlation coefficients of water temperature and blue-green alga abundance were statistically significant, while those of electrolytic conductivity and alga were negative. There was no correlation between the orthophosphate concentration and the blue-green alga count. Increases in the numbers of Planktolyngbya brevicellularis were observed in the widest temperature range (160C-260C), whereas Limnothrix redekei developed in a temperature range of 190C-220C, and Aphanizomenon gracile in a range of 200C-220C.

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Annual succession patterns of blue-green algae as related to physicochemical water parameters in the urban Lake Jeziorak Mały in the 1998 - 2003 period

Zębek E.

Oceanological and Hydrobiological Studies

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2005

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Vol. 34, No.4

33--46

EN

Studies on net phytoplankton were conducted in the urban Lake Jeziorak Mały (Mazurian Lakeland) in the 1998-2003 period. Changes in the numbers of blue-green algae were analyzed in the annual cycle with respect to water temperature and orthophosphate concentration. An increase in water temperature above 13oC was followed by an increase in the population density of bluegreens. Two abundance peaks of blue-green algae were recorded in the summers of 1998, 1999, and 2002 and one in the summers of 2000, 2001, and 2003. The coefficient of correlation between water temperature and the occurrence of blue-greens was statistically significant, but no statistically significant correlation was found between orthophosphate concentration and the abundance of blue-green algae. From May to August, under conditions of the domination of bluegreen algae (over 50% of the total phytoplankton biomass) and water temperature exceeding 19oC, this correlation was negative and statistically significant. This suggests that over this period the blue-greens could contribute to reducing the concentration of orthophosphates in the water.