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4 Oceanological and Hydrobiological Studies

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Diatom biomonitoring : scientific foundations, commonly discussed issues and frequently made errors

100%

Szczepocka E. , Żelazna-Wieczorek J.

tom Vol. 47, No. 3

313--325

Contemporary assessment of the ecological status of aquatic ecosystems is based on various groups of organisms, including diatoms. Biological assessment, implemented by the Water Framework Directive, has been applied worldwide for more than 15 years. Currently, the most basic “tool” used in biomonitoring are diatom indices, which are routinely applied in Europe and other countries around the world. In Poland, the diatom indices have been used for over 5 years, which is a period of time allowing to summarize and evaluate the effectiveness of these methods in the assessment of aquatic ecosystems. The purpose of this work was to analyse the use of diatom indices in the biomonitoring of surface water by collecting data on the possibilities and limitations of using diatom indices for the objective assessment of water quality. Attention was paid to mistakes made in the course of biological assessment performed with the use of diatom phytobenthos, which have a significant impact on the obtained results. The paper also contains suggestions for introducing several important changes in biological monitoring, which will improve its quality and efficiency in assessing the ecological status of various aquatic ecosystems.

Diatom indices and stream typology in Estonia

88%

Vilbaste S. , Järvekülg R. , Pall P. , Piirsoo K. , Trei T. , Viik M.

tom Vol. 33, No. 1

3--10

This paper deals with the use of diatom indices in the assessment of streams in Estonia. The problem addressed is how rational it is to determine different types of streams or stream reaches based on diatom research. At the moment, there are five different typologies of running waters in Estonia, two of which are analyzed here. Diatom indices can be employed to assess the ecological quality of water but not the status or type of stream. The most promising diatom indices for such assessment are the Trophic Diatom Index, Watanabe Index, Descy Index, and Schiefele & Schreiner Index.

Benthic diatoms of the Vrla River (Serbia) and their application in the water ecological status assessment

88%

Jakovljević O. , Popović S. , Živić I. , Stojanović K. , Krizmanić J.

tom Vol. 45, No. 3

304--315

Epilithic diatoms from the Vrla River (Serbia) have been used to assess the ecological status of water. A total of 227 diatom taxa belonging to 50 genera were identified in the Vrla River during six research seasons with 13 dominant species recorded. Gomphonema (30 species), Navicula (28) and Nitzschia (26) were the most species-rich genera, followed by Pinnularia (12) and Encyonema (11). One taxa was recorded as new to Serbia – Geissleria acceptata. CCA grouped the diatom taxa into three main groups. The first group included taxa found at most of the sampling sites, the second group involved diatom taxa significantly positively correlated with the oxygen, while the third group showed positive correlation with temperature. RDA showed that some diatom taxa, including: Cocconeis placentula var. placentula, C. placentula var. lineata, C. pseudolineata and Mayamaea atomus var. permitis, are significantly positively correlated with temperature, while others, for example Achnanthidium minutissimum, Hannaea arcus, Nitzschia pura are mostly correlated with total phosphorus, alkalinity and water hardness. The ecological status of the Vrla River ranged from moderate, good to high. It was shown that according to the diatom indices, the ecological status of water downstream and upstream of a trout fish pond was slightly different.

Using benthic diatom communities and diatom indices to assess water pollution in the Puck Bay (southern Baltic Sea) littoral zone

75%

Bogaczewicz-Adamczak B. , Dziengo M.

tom Vol. 32, No. 4

131-157

The subject of the study were the benthic diatom communities of the Puck Bay littoral zone. Samples of the sediments were taken from sites situated near the sewage treatment plant at Swarzewo from June 1998 to May 1999. The analysis of the species composition and the relative percentages of the diatom indicative groups were used to evaluate water quality. The following ecological factors were taken into consideration: salinity, trophic status and saprobity. Following Lange–Bertalot (1979), water quality was classified based on a 5-degree scale of saprobity. It was correlated to the percentages of the sensitive, tolerant and resistant diatoms taxa and their reaction to organic matter content. The water quality evaluation was tested with the diatom indices using Omnidia 3 software. The results of the diatom studies indicate that the dominating groups were the oligohalobous and mesohalobous taxa, which are characteristic of eutrophic waters and contain biogenic compounds, mainly nitrogen and phosphorus. The most abundant groups in the saprobic spectrum were the resistant (á-mesosaprobic, polysaprobic) and tolerant (β-mesosaprobic, β/α-mesosaprobic) diatoms, which are indicators of water purity class II (III), and in summer, predominantly class III. The comparison of the results of diatom analysis of the Puck Bay microphytobenthos obtained with the Lange–Bertalot (1979) method and those acquired with Omnidia 3 software demonstrates the possibility of applying it to evaluate environmental status and assess polluted brackish waters.