Volume 38 (2009): Issue 3 (September 2009)

Indoor artificial streams were used to evaluate the short-term (24 day) influence of copper and zinc, individually and in combination, on the biomass and taxonomic composition of algal periphyton communities. The effects of Cu (50 μg 1^-1) and Zn (1 mg 1^-1) were assessed using measurements of biomass, ash-free dry mass (AFDM), chlorophyll-a concentration, taxonomic composition and biovolume. In artificial streams with Cu, Zn and Cu+Zn, there were significant (p > 0.05) reductions of chlorophyll-a concentrations, dry mass and AFDM, and also changes in the species diversity and relative abundances of periphyton species. In artificial streams containing both Cu and Zn the taxonomic composition shifted from a Cyanophyceaen dominated community to one consisting mainly of Chlorophyceae, whilst the relative contribution of Bacillariophyceae was not significantly altered.

Chironomus f. l. plumosus larvae, a valuable food of bream (Abramis brama (L.)), dominate in the benthos of the extra-littoral zone of the shallow, lowland, eutrophic Zegrzyński Reservoir. Bream is the dominant fish species in this reservoir, making up to 80% of total net catches. During eight years of studies, very regular Chironomus population dynamics were noted in the lotic part of the central, broad basin of the reservoir. There were usually two peaks of the abundance: the higher one in spring, and the much lower one in late summer. Both peaks of Chironomus abundance positively correlated with commercial net catches of bream in the reservoir in particular years. The total bream catch per year in the reservoir studied also correlated positively with the average yearly abundance of Chironomus. The correlation between Chironomus abundance and bream occurrence (measured by commercial net catches) in the reservoir studied suggests that this environment is used by bream mainly as a feeding ground. In the years with a low spring Chironomus peak of abundance, the bream leave the reservoir, searching for food in its inflows - two large, lowland rivers. This corresponds to much lower catches noted in the reservoir in the years of low Chironomus abundance.

Research relating to the subject of this paper was conducted on the Tywa River between September 1996 and July 1998. In the samples, invertebrates were found belonging to 46 species, 26 genera, and two subfamilies. In the 1996 season, the highest abundance was observed among Tanypodinae (larvae) at 10,878 ind. m^-2; among Chironominae (larvae) it was 9,965 ind. m^-2; and among Tubifex tubifex it was 2,605 ind. m^-2. The maximum total density of macrozoobenthic forms in the Tywa River was at station no. 1, where it amounted to 23,953 ind. m^-2. The quantitative structure in the 1997 season was lower than in the 1996 season, and the highest abundance was for Simulium sp. (larvae) at 5,196 ind. m^-2; for, Tanypodinae it was 3,360 ind. m^-2; and for Dreissena polymorpha it was 4,721 ind. m^-2; and for Theodoxus fluviatilis — it was 4,114 ind. m^-2. In this season, the biodiversity of the macrozoobenthic community was the highest of all seasons. In 1998, the qualitative structure of the macrozoobenthic community was low: Hirudinea disappeared, and the quality of the community was almost four times lower than in 1996. The river's fast current, its diverse substratum, its very good oxygenation, and moderate concentrations of organic matter created conditions appropriate for species that differ in their requirements.

Delayed luminescence is the phenomenon of long-lived emission of light by living plants and cyanobacteria after being illuminated with light and put into darkness. This study presents uses of this phenomenon as a tool for monitoring the chlorophyll a concentration in phytoplankton. The luminescence method was used on natural phytoplankton from the surface waters in tributaries supplying Lake Miedwie and compared with the commonly used spectrophotometric method of determining chlorophyll a concentrations.

The aim of the present paper is to present the results of a study on the impact intensive carp (Cyprinus carpio L.), feeding with extruded commercial feed has on the quality of cooling waters. The feed studied had varied fat and carbohydrate contents. The study also revealed the optimal hydrochemical conditions of cooling waters for carp farming. Cage farming caused growing loads of organic matter, nitrogen, and phosphorus in the water. Experimental extraction of feed from the water revealed that high fat fish feed was more stable in comparison to high carbohydrate fish feed. Intensive carp farming with these two feeds led to considerable fish weight gain in both feed groups, but the weight gain for the carp fed with high fat feed, in comparison with that of carp fed with high carbohydrate fish feed, was significantly greater (p<0.01).

This paper discusses preliminary research on using photoinduced luminescence phenomena in determining the structural properties of humic acids extracted from the bottom sediments of two lakes. The lakes examined differ in the hydrochemical parameters of the water body, as well as in the drainage basins surrounding the lakes. Photoinduced luminescence of humic acids was induced with a halogen light of 1500 μmol m^-2 s^-1 photon flux density. The differences observed are evidence of both the variable qualitative and quantitative contribution of photoluminophors to the structure of the examined humic acids, and of their different photochemical activity. Furthermore, photoinduced luminescence intensity depends on the degree of transformation of the humic acids.

This study presents and discusses the result of research on the chemical composition of bottom sediments of throughflow lakes located in Drawieński National Park. Basic hydrochemical indicators of the studied sediments are discussed: total organic carbon (C_org), total nitrogen (N_tot), and the C_org/N_tot ratio, which shows the rate of organic matter mineralization. The research and the analysis of the results show that the quality of the studied sediments changed with their distribution in the lake basin. The highest C_org and N_tot values were noted in sediments accumulated in the maximum depth of each lake, and at the inflow and outflow from the first lake in the whole cascade of throughflow lakes. Low C_org/N_tot ratios indicate that most of the sedimentary organic matter in the throughflow lakes comes from aquatic organism production, but the small participation of land-plant organic matter delivered to the lakes is also shown.

The subjects of the study were two high-mountain lakes, Morskie Oko and Czarny Staw pod Rysami, in the Tatra range of the Carpathian Mountains located within the protected area of the Tatra National Park. This paper presents results of the analytical study of the lake water composition and compares this with relevant data from earlier years. The impact of the following factors was distinguished and discussed: atmospheric deposition (dry and wet), migration of pollutants with runoff water supplying both reservoirs, tourism (hiking, climbing), and the influence of mountain hostels. The resistance and sensitivity of the lakes to human impact is described in terms of water quality changes and characteristics of the catchments and the region.

Assessment of the ecological status of an aquatic environment according to the European Union Water Framework Directive (WFD) requires the determination of a link between the observed status of the marine ecosystem and catchment loading as well as the establishment of criteria for ecological status definitions. This article presents the results of a study identifying links between environmental pressures in the Polish sector of the Baltic Sea and state parameters applied in the assessment of eutrophication. Strong, statistically significant correlations were found between riverine loads of nutrients and their marine concentrations even in relatively short time data series.

To implement the EU Water Framework Directive (WFD) it is necessary to establish tools enabling ecological status quantification on the basis of biological indicators, and to assess reference conditions and relevant environmental pressures for the construction of response curves. This study focuses on the Polish sector of the Baltic Sea. A number of statistically significant linear correlations, linking chlorophyll-a concentrations with pressure parameters, were found. Due to the lack of historical data, reference conditions and ecological class boundaries for chlorophyll-a assessment were determined using a simplified mathematical approach.

The implementation of the EU Water Framework Directive (WFD) requires ecological status quantification on the basis of biological and physico-chemical parameters, and an assessment of reference conditions and relevant environmental pressures for the construction of response curves. In this study the linking of water transparency, a proposed eutrophication indicator, to environmental pressure parameters was examined in the Polish sector of the Baltic Sea. Statistically significant linear correlations were detected between nutrient concentrations in sea water and Secchi depth, and between nutrient riverine loads and Secchi depth. The magnitude of acceptable deviation from reference conditions is also discussed.

Different morphological features of particular water bodies, physical and chemical factors of their waters and sediments will have an impact on the development of specific aquatic vegetation types, which in turn will affect the creation of specific communities of plankton organisms. Therefore the aim of this study was to analyse the quantity and quality changes of macrophyte structure in relation to the lowering of the water level. Furthermore, the relationship between zooplankton community densities and environmental parameters was studied. Another aspect of the study was to investigate the similarity of the zooplankton communities of particular sampling stations in the three examined seasons.

The study was carried out on Dąbrówka water body, a shallow and macrophyte-dominated pond, situated 10 km west of Poznań, Wielkopolska region, western Poland. The examination was conducted in the three seasons: spring, summer and autumn.

The results revealed that during one vegetative period, including three seasons — spring, summer and autumn, three different layouts of aquatic vegetation were obtained, which reflected a significant transformation in the macrophyte cover. Along with the lowering of the water level the structural changes, especially in the case of submerged vegetation were recorded, which in each season was represented by different dominating species.

Only three significant correlations between zooplankton densities and environmental factors observed. Negative relationship concerned total nitrogen and two positive related to biometric parameters of the macrophyte habitat (plant biomass plant stem volume). The plant biomass was a predictor of cladoceran abundance and plant stem volume referred to rotifers, which may reflect the complexity of the aquatic plant habitat, indirectly relating to the effectiveness of the macrophyte stand as anti-predator refuge.

The analysis of the similarity of the zooplankton communities of particular sampling stations in the three examined seasons did not reveal any clear relationship, either in relation to a particular season or a sampling station. The participation of eutrophic species was highest in the spring and lowest during the autumn season. The open water zone possessed the highest participation of these species compared to the macrophyte zones.

During investigations of an inundated opencast sulphur mine (an open, deep water habitat with a relatively small littoral area) only five species of breeding water birds were recorded. The density of breeding great crested grebes Podiceps cristatus was relatively high (c. 1.0-1.1 pairs 10 ha^-1 of water, and 1.6-1.8 pairs ha^-1 of the macrophyte area) although fish density was very low. High water transparency probably compensated for low prey density, because potential prey could be readily detected. Most of the fish were small and occurred in the upper layers of the water column (they could not live below 10 m where the water was anoxic), so were readily available and easily caught by the grebes.