The article presents the results of research on the transport of sediment carried by the rivers of the northern slope of the Pomeranian Lake Land to the Baltic Sea in the years 1961-1980. The research includes rivers flowing into the open sea: Rega, Parseta, Wieprza, Slupia, Lupawa and Leba. The total surface of the basins of the rivers in question amounts to 13825.1 km2. The analysis was conducted on the basis of the data concerning the turbidity and flow of the rivers included in hydrological year-books. The size of the transport of the sediment for respective rivers has been counted and the transport of the wash load was analysed with respect to changing conditions of the streamflow and to physical-geographical features of the basin. The transport of the sediment carried to the sea was estimated (46000 tons) and the participation of the rivers of the northern slope of the Pomeranian Lake Land in the total transport of the river wash load from the catchment area of the Baltic Sea has been estimated (0.63%).
Phytoplankton structure (abundance, taxonomical structure, species diversity) as well as physico-chemical factors (tem-perature, pH, electrolytic conductivity, oxygen concentration) were observed in a natural, shallow, small lake. The comparison of three zones within the studied lake showed distinct trophic differentiation. The biodiversity indices, which were used in this analysis, appeared to be useful in determining the lake functions.
The development of the blue-green algae in the Gulf of Gdansk begins in May and lasts till October. To the stable compo-nents of the filamentous forms belong Aphanizomenon-flos aquae, Nodularia spumigena, Planktolynbya limnetica, Pseudanabaena limnetica and Planktothrix sp. The coccoid forms are represented by Snowella septentrionalis, S. lacustris, Merismopedia punctata, M. tenuissima, Woronichinia compacta, Rabdogloea linearis, Cyanodictyon imper,fectum, C.planctonicum. In the years 1992 and 1993 the openwater area of the Gulf of Gdansk was characterised by the summer (July) domination of two species of blue-green algae: Microcystis aeruginosa and Aphanizomenon flos-aquae. The presence of Nodularia spumigena was also noticed. In 1994, the extremely dense bloom of Nodularia spumigena occurred with the biomass increase to 130 mg?C? m^3. The intensity of this bloom could be linked to temperature which in summer 1994 was very high and reached over 22?C. In the years 1996 and 1997, temperature did not attained so high values and the intensity of blooms was lower.
The material studied originated from the marine Holocene sediments of the Gulf of Gdansk and from Kiel Bay. During the diatom analysis, the interest was focused on the dominance of Chaetoceros resting spores. An abundant occurrence of such resting spores was interpreted in terms of changes of environmental conditions in the study areas. In the fossil sediments, it indicated the inflow of the oceanic waters which caused the salinity increase and the natural rise in the nutrient content, whereas in the subfossil sediments, it marked the increasing human impact.
The impact of some organotin compounds (10-200 mg dm^3) on the planktonic cyanobacterium Synechocystis aquatilis was studied. The following order of toxicity of organotins tested to the cyanobacterium culture was found: DBTCl>TPTAclTBTCl? TPTCl>TMTCl. Chlorophyll a content in the culture seemed to be more susceptible to organotins than cyanobacterial growth. The inhibition of both parameters increased significantly with the increase of compound doses, time of exposure and decrease of initial culture density. After 96 h exposure, the chlorophyll a content in the cyanobacte-rium cultures of the initial density 56 mg dry wt dm^3 was reduced for 200 mg dm^3 of DBTCl, TBTCl and TPTCl by 70%, 50% and 20% respectively, while in the cultures of the lowest initial density (10 mg dry wt dm-3) by 90%, 75% and 50%, as compared to the organotin free controls.
A biomonitoring program was developed to assess the ecological status of streams based on the phytobenthic algal community structure. The study presented here focuses on siliceous sites of streams in the central highlands of Germany. Phytobenthic algae belonging to eight classes and 74 taxa were grouped into four categories according to their ecological distribution pattern. A formula was designed to calculate an index ranging from +100 to ?100 to assess stream health. Based on these values, the sampling sites were assigned to one of the five ecological quality classes required by the Water Framework Directive (WFD) of the European Union.
Free fatty acids concentrations and composition in dissolved and particulate fraction of the Baltic Sea surface waters (The Gulf of Gda?sk, the Gda?sk Deep and the Gotland Deep) and the Vistula waters were determined by means of fatty acids coumaryl esters HPLC analysis. Total concentrations of dissolved fatty acids were stated between 0.14 and 13 mg ?dm-3, whereas of particulate fatty acids between 16 and 50 mg ? dm-3. The concentrations depended strongly on the time and location of sampling. Palmitic acid was the dominant one in all inves-tigated samples. It was revealed that the total concentration as well as the percentage composi-tion of individual acids (especially polyunsaturated acids) in surface waters were related to the intensity of biological processes of the investigated area. The autochthonous phytoplankton blooms were the main source of fatty acids in the Baltic Sea surface waters.
A model was developed to describe the material uptake and biodeposition of bivalve Mytilus edulis. The existing blue mussel organism level models are based on contradictory assumptions and no agreement has still been found regarding the processes and environmental factors to be included into the model. A reconciliation of contradictory approaches was successfully done in the present model. Using seston concentration, seston organic content and mussel size as input data, the model is able to predict the uptake of suspended material, selection of organic particles and material allocation as pseudofaeces, ingested, assimilated fractions and faeces. The results of the model application to mussels in the south-eastern Baltic conditions are discussed.
The initial results of modelling of suspended matter (SPM) concentration are presented. The three-dimensional model proposed allows one to calculate the transport, erosion and deposi-tion of a mineral part of seston in the Gulf of Gdansk. The loads of SPM from rivers, atmosphere and the open sea, based on either real data or other model simulations, are included. In this model, the settling velocity of seston particles is assumed to be proportional to the Stokes' one computed for particles of 4 mm in diameter. Erosion and deposition rates depend on the bed shear velocity computed from hydrodynamic model. Results of computations corresponding to a period of one year are compared with in situ ob-servations carried out in the 1996 year and satellite data. In general, horizontal and vertical distri-butions of mineral SPM concentration computed from the model show a characteristic for this area pattern of water turbidity, however, quantitatively the results obtained are in rather poor accordance with real values.
Benthic diatom samples were collected from 45 potential reference river sites in Ireland. Diatom samples were also collected from 24 lowland eutrophic sites. The main objective for sampling the potential reference sites was to determine the type-specific biological typologies represented by these sites. The lowland sites were sampled as part of another project and are used here for comparative purposes. A larger number of taxa was identified from the reference sites (175 species) in comparison with the lowland sites. (71 species). Distinct differences in diatom distribution and diversity between the reference sites and the lowland sites were revealed by DCA analysis. DCA analysis also showed that the original typological classification of the reference sites was not reflected to any extent in the distribution of benthic diatoms between these sites. However, there was some differentiation between the reference river sites with respect to diatom distribution along axis 1 of the DCA ordination and this was strongly correlated with water conductivity.
In this study the concentrations of trace metals in typical parasites of the three-spined stickleback, i.e. Schistocephalus solidus (Cestoda) and Thersitina gasterostei (Copepoda), and in the sticklebacks (infected or uninfected) were compared. Concentrations of Mn, Co, Ni, Cu, Zn, Cd and Pb were determined. The accumulations of metals suggested that S. solidus, T. gasterostei and their hosts could serve as biological indicators of heavy metal contamination.
The Gdansk - East Wastewater Treatment Plant (WWTP) with its predicted average discharge of 2 m3 s-1 is the largest treatment plant with an outfall pointing into the Gulf of Gdansk. The discharge of only mechanically treated wastes into the final kilometre of the River Wisla gave rise to serious environmental problems in the coastal zone. This paper discusses the situation in 1995 and the possible relocation of the outfall based on hydrodynamic conditions. Numerical modelling has been applied to estimate the area influenced by treated water discharged at a variety of locations. The analysis indicates that the optimum location for the outfall would be approximately 2500 metres offshore.
Generic composition and metabolic activity of neustonic and planktonic bacteria inhabiting seawater in the region of the Gdansk Deep were determined. In each of the studied water layers, bacteria of the Flavobacterium-Cytophaga group domi-nated, while bacteria of the Micrococcus, Acineto-bacter, Bacillus genera and of the Arthrobacter-Corynebacterium group constituted only a slight percentage of the bacterioneuston and bakterioplankton. Different levels of metabolic activity of bacteria inhabiting different water layers were measured. The intensity of oxidization of respiratory substrates depended also on taxonomic position of bacteria. Generally casein hydrolyzate was the most actively metabolized respiratory substrate; sodium acetate was oxidized with lesser intensity. A considerable impact of salinity on the level of metabolic activity was noticed.
Concentratin of total mercury was determined in muscle tissue of cod Gadus morhua, herring Clupea harengus, eel Anguilla anguilla, calpout Zoarces viviparus, perch Perca fluvitalis, pikeperch Stizostedion lucioperca, sand eel Hyperoplus lanceolatus, round goby Negobius melanostomus, brown trout Salmo trutta, trout Salmo gairdneri, flounder Platychtis flesus, turbot Psetta mazima, smelt Osmerus eperlanus and sculpin Cottus scorpius caught in the Gulf of Gdansk in 1986-1993.The measurements of mercury concentrations were performed by the method of cold vapour atomic absorption spectrmetry (CV-AAS), after wet digestion of samples with concentrated nitric acid.The highest mean concentration of mercury was found in eelpout, the lowest one in pikeperch.The possitive linear correlations has been found between the body length and mercury concentration in perch, eelpout, sand launce and flounder.
Seasonal and daily changes in the fish community and variations between commercial and non-commercial fish abundance were monitored in the inshore waters of the western part of the Gulf of Gdask (the Sopot territory). Samples were collected from December 1998 to December 1999, though monthly samplings, and supplemented by 24-hour investigations taken every three months, using a two-meter wide trawl. Among the 16 species collected, 5 were commercial and 11 were non-commercial. Juvenile forms of herring and flounder dominated the commercial fish; the highest catches were in March (89 ind. 100 m-2). Among the non-commercial fish, two species of Gobiidae (sand and common goby), and three-spine stickleback were most frequently caught. During the 24hour observations, commercial fish were noticed mostly at night. The investigated area is an important zone for both juvenile commercial fish and some ecologically important uncomercial species.
A total of 861 specimens of Sardinella aurita were collected from month-ly trash catches from a trawling net operating on the Port Said coast on the Mediterranean Sea from January to December 1997. The species constituted 17.9% of the trash catch and about 3% of the total catch of the gear. The juveniles of S. aurita stayed at the nursery grounds from September till March, and recruited from September till December. The length-weight relationships as well as the condition factor of the juvenile fish were studied. The highest values of the condition factor were recorded in autumn. The feeding activities were quite high during the early winter and autumn. The juveniles of S. aurita are likely to feed in the upper water level (planktonivorous).
The Swelinia Stream is one of several streams discharging into the Gulf of Gdansk in the Sopot coastal zone. The stream is inhabited by a great variety of benthic diatom flora, among which freshwater alkaliphilous diatoms, typical of eutrophic waters, are predominant. The $-meso- and $/'-mesosaprobic diatoms typical of waters moderately polluted by organic matter prevail within the saprobic groups. Xenosaprobic diatoms occur only occasionally. Quantitative analysis of diatoms, classified according to their saprobic requirements into taxa sensitive, tolerant and resistant to organic pollution, has shown that the water quality is deteriorating downstream. Evidence for this was the absence of class I water in the stream's lower course; the usual quality level is class II, which may even drop to class III in the summer and autumn.
Results of monitoring carried out in the coastal zone between Kuznica and Gorki Wschodnie (down to 20 m depth) in autumn 1994 and summer 1995 are presented. These investigations were a continuation of measurements taken in the areas of Hel and Krynica Morska in summer 1992 (down to the 60 m depth). The state and directions of seasonal and multi-annual changes of chemical, micro-biological and biological properties of the water and sediment environment of the Gulf's coastal zone are discussed. The results of presented investigations and of experimental research carried out in the Gulf of Gdansk environment were the basis for the development of a system for protection and regeneration of the biocenosis of the Gulf.
The paper results of a study on general chemical indicators of surface water quality carried out in Roztoka Odrza?ska in 1982-1994.The parameters in question were: oxygen content, chloride, nitrate and dissolved phosphate concentrations and BOD5. An attmept was undertaken to determine the influence of the Odra River flow on the chemical status of Roz-toka water. Threshold values of Qs were determined in three regimes of water transport: a back flow of water from the Szczecin Lagoon in the full river-bed and bidirectional (two-layered) water movements - with back flow prevailing and with riverine inflow prevailing.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.