Wyniki wyszukiwania - Biblioteka Nauki

1

The sorption and removal of heavy metals by algal biomasses

100%

Pawlik-Skowronska B. , Pirszel J. , Skowronski T.

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tom 27

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nr 1

79-90

EN

Metal sorption capacity of Chlorella kessleri and two strains of cyanobacteria (Aphanocapsa sp., Anabaena flos-aquae) was studied. It was found that among studied organisms, dead cells of C. kessleri were the most effective sorbents of Pb, Cu, Cd and Zn. They displayed the highest cation-exchange (Cd2+/H+) capacity and bound much more Cd and Zn at pH 7 than at pH 4. The optimum pH for sorption of Pb and Cu was 6. At pH 6, dead cells of C.kessleri could bind maximally about 37 mg Cd, 38 mg Zn, 21 mg Cu and 70 mg Pb per g of dry weight. Generally, algal dead cells (0.3 g dry wt dm^3) removed 50-70% of the metal ions from 0.01 mM solutions. A surplus of calcium and magnesium caused a slight decrease of Pb, Cu, Cd and Zn sorption.

2

Eucaryotic algae and cyanobacteria in the river dunajec upstream and downstream from the new dam reservoirs in Czorsztyn and Sromowce and their use for monitoring

88%

Mrozinska-Broda T. , Czerwik-Marcinkowska J.

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nr 3

83-97

EN

This report presents results of the studies conducted in 2002 of eukaryotic algae and cyanobacteria found in the River Dunajec in the area of the newly built dam reservoirs in Czorsztyn and Sromowce. The studies demonstrated that diatoms were the dominant group in both the river (at 74 %) and the dam reservoirs (at 32 %), and that among the diatoms collected, eutraphenthic [van Dam et al. 1994] species usually prevailed. The diatom group, characterized by a broad ecological scale (tolerant), predominated slightly only at Station 3 located downstream from the dam reservoirs. This variation, which was probably connected with improved water quality in this part of the river, was the result of the sedimentation of pollutants in the dam reservoirs. Equally unexpected was the mass development of Didymosphenia geminata in this area. It occupied not only spots in the riverbed of the River Dunajec, but it also spread to the riversides and even to the river arms close to the confluence of the streams flowing from the Pieniny Mountains. The quantitatively dominant species in this area was Cladophora glomerata, which is an excellent habitat for other algae, particularly diatoms. The ultrastructure of its cell and cell wall is of great significance since it reflects the environmental conditions in which it lives. The ultrastructure of the Cladophora glomerata that occurred at different stations did not differ significantly, nor did it indicate the existence of any considerable hazard resulting from environmental pollution.

3

The role of nitrilotriacetic acid as a modyfying factor of phytoplankton growth

88%

Kosakowska A.

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tom 27

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nr 1

61-68

EN

The paper presents results of studies on the influence of fresh and aged for 6-12 months aqueous solutions of nitrilotriacetic acid (NTA) on the growth of phytoplankton cells. Axenic strain of unicellular algae Scenedesmus microspina (B2-76) and cyanobacteria Chroococcus minor (A-101) (Gleocapsa minor) were used in the experiments as test organisms. These or-ganisms are common in waters of the Gulf of Gdansk and are important components in the food chain. Concentration of chlorophyll a in test cultures served as a measure of the growth of phytoplankton cell studied. NTA, when added to the culture of Scenedesmus or Chroococcus in the concentration range from 1 to 50 mmol/dm3 exerted a strong growth promoting effect on the cells. NTA solutions aged for 9-12 months stimulated the growth of cyano-bacteria Chroococcus minor to a much larger extent than green algae Scenedesmus microspina. These results indicate that the biological activity of NTA, after long-term incubation as an aqueous solution, undergoes a considerable modification. The effects biological of the end products of such a modification depend on the time of adding of NTA, its initial, concentration as well as on the sensitivity of phytoplankton strains. It is concluded therefore that, the presence of NTA in estuarine and coastal waters may significantly affect the metabolism and growth of phytoplanktonic cells, especially cyanobacteria.

4

Cyanobacteria ? the source of biologically active substances

75%

Glowacka J. , Waleron M. , Szefel-Markowska M. , Lojkowska E. , Waleron K.

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nr 4

95-112

EN

Cyanobacteria (blue ? green algae) are one of the largest group of Gram ? negative, photosynthetic prokaryotes, which are morphologically diverse and highly widespread in salt and sweet water and also in terrestrial habitats. They play a significant role as primary producers in many ecosystems. Some species of Cyanobacteria are capable to grow extensively and formate toxic water blooms which can be dangerous for animal and human health. Certain species of them produce a wide variety of bioactive compounds which can have potential biotechnological cosmetical and pharmaceutical applications. Cyanobacteria have recently been identified as one of the most promising group of organisms from which large number of novel, biochemically active natural compounds can be isolated.

5

Response to drying of cyanobacteria and algae communities in Tatra Mts stream (Poland)

75%

Kawecka B.

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nr 1

27-38

EN

The structure, dynamics and chlorophyll a content of lithoreophilous communities of Cyanobacteria and algae in two periodically drying sectors of the stream: in its upper (alpine ), and middle part (forest) zones were investigated. In both sectors the diversity of species was low. After snow melt, in the upper part, the stones were successively colonized by Cyanobacteria (with Chamaesiphon polonicus (Rostafinski.) Hansgirg prevailing), and green alga Klebsormidium rivulare (Kutz.) Starmach, finally obtaining stable and abundant communities. In the middle part of the stream, a spring explosion of Klebsormidium rivulare and species from the Chlorococcales group was observed. They developed temporary, since they disappeared after the June spate. Later this area was colonised mainly by Homoeothrix janthina (Bornet et Flahault) Starmach, Hydrurus foetidus (Villars) Trevisan, and diatoms, coming from a neighbouring non drying part of the stream. The chlorophyll a content in both sectors was low (2 - 55.8 mg m ?2) .