Two rivers situated in Central Poland, the Bzura and the Pilica, were selected for analysis of their water quality using benthic diatom species as indicators. The Bzura River has previously been strongly contaminated with organic pollutants, while the Pilica River has been classified as having good water quality. Samples were collected from nine sites along the Bzura in April 2003 and seven sites along the Pilica in April 2006. The main aims of the study were to determine the dominant diatom species present in the rivers and to assess their usefulness as biological indicators. Water quality of the rivers was estimated on the basis of the SPI -Specific Pollution sensitivity Index (CEMAGREF 1982) and the GDI -Generic Diatom Index (Coste, Ayphassorho 1991) while trophic status was estimated using TDI -Trophic Diatom Index (Kelly, Whitton 1995 18Indices determining saprobic water pollution (SPI, GDI) indicated water quality of class III and IV for the Bzura River and class II and III for the Pilica River. The trophic status determined on the basis of the TDI index revealed the Bzura water to be classified in the eutrophic-tohypertrophic zone and that of the Pilica River to the oligo-mesotrophic-to-eutrophic zone.The diatom taxa that dominated in the Bzura River were species that are generally considered to be tolerant and resistant with respect to organic water pollution, including: Cyclotella meneghiniana Kützing, Gomphonema parvulum (Kützing) Kützing, Nitzschia palea (Kützing) W. Smith, Nitzschia paleacea Grunow, Sellaphora pupula (Kützing) Mereschkovsky, Stephanodiscus hantzschii Grunow, Ulnaria ulna (Nitzsch) Compere. In the Pilica River diatoms from groups that are sensitive and tolerant to organic pollution were seen to dominate, such as:

The aim of the study was to compare the biological analyzes of the Linda River (Central Poland), which were based on three diatom indices: IO, GDI and IPS in order to select the best diatom index for the biological assessment of the lotic water quality. Additionally, the summary of the selected results of the biological and chemical analyzes was presented to show how precise the biological analyzes are as a basic tool in the assessment of the ecological status of the lotic waters. The results showed that each of the indices assessed the water in the Linda River to a specific but different quality class. The IO index showed class II of the water quality, while the IPS and GDI − class III. Statistical analysis conducted with the nonparametric Kruskal-Wallis test for independent samples (Kruskal, Wallis 1952) showed that differences in the values of individual indices * Corresponding author: szulc@biol.uni.lodz.pl at different sites were not statistically significant. It should be noticed that the IPS and GDI indices gave values that classify the water in the Linda River at least one class below.The obtained results confirmed that the biological methods are most reliable in the assessment of the water quality. These methods are less sensitive to a single impact of the environmental factors, therefore they permit accurate determination of the ecological status of the water ecosystems.

The main aim of this study was to assess the usefulness of the Biological Diatom Index (BDI) (Lenoir & Coste 1996) for the estimation of water quality in the central section of the Pilica River, located in central Poland in Łódź province. The BDI has never been used before to monitor Polish surface waters. An analysis of the correlations between the values of the BDI and selected physico-chemical parameters was performed, as was an assessment of water quality using the BDI. On the basis of value ranges proposed by Descy and Ector (1996), a good ecological status in the Pilica River was obtained, but this did not correspond with the results achieved from the physico-chemical analysis. This study proposes new value ranges for the BDI. With these new values, the ecological state of the Pilica River changed from good to moderate, which corresponded with the physicochemical analysis of the water. The new, proposed value ranges for the BDI assess more precisely the quality of water in lowland Polish rivers.

I n t e r n a t i o n a l J o u r n a l o f O c e a n o g r a p h y a n d H y d r o b i o l o g y by The Oceanological and Hydrobiological Studies is online at oandhs.ocean.ug.edu.pl pages (236-244) AbstractThe objective of the studies included a complex of three reservoirs (upper, middle and lower Arturówek) which play an important recreational role for the residents of the Łódź city and the surrounding areas. The reservoirs were constructed on the Bzura River and are located in the area of the Łódź Hills Landscape Park. The river, the ecological status of which was defined as moderate, has a great influence on the quality of water in the Arturówek reservoirs. A total of 36 planktonic samples were collected in 2011-2013 during spring, summer and autumn seasons. During the studies, the selected physical and chemical parameters were measured. In addition to taxonomic analysis of Cyanobacteria and algae, the analyses of abundance and biomass of phytoplankton and the concentration of microcystins in water were conducted. In 2013, ecohydrological rehabilitation of the Arturówek reservoirs was carried out. Investment works included: removal of the bottom sediments to reduce internal loads, construction of buffer vegetation zones (ecotones) and sedimentation-biofiltration systems to reduce the amounts of pollutants flowing into reservoirs with rainwater. Significant changes in the structure of phytoplankton were observed in 2013. Every year, the disappearance of Cyanobacterial blooms was observed in favor of an increasing contribution of algae.

Peat bogs are unique and important habitats for biodiversity at the species and ecosystem level where low pH of water plays a major role. The main objective of the present study was to compare the benthic diatom assemblage structure of the selected part of the Fenn's and Whixall Mosses complex in order to verify whether selected sampling sites differ from each other. The complex is a cut-over, lowland raised mire, which is a National Nature Reserve (NNR) and a Site of Special Scientific Interest (SSSI).Altogether 92 diatom species were identified in 72 benthic samples collected between September 2008 and August 2009 from six selected sampling sites. Statistical cluster analysis was used to classify diatom samples and to observe the structure of * Corresponding author: szulc@biol.uni.lodz.pl diatom assemblages. The results of this analysis grouped the data set into 3 clusters with 24 samples from each of the two sampling sites in one cluster. Such a clear division shows that pH of water has an impact on the species composition, the richness and diversity of benthic diatom assemblages.

Diatoms of the genus