This paper presents the results of investigatoins on activity of proteases, amylases and lipases synthetized by estuarine bacteria.The highest lavels of activitry of the enzymes studied were observed in bacteria from hypertrophic lake Jamno, the lowast in bacteria from eutrophic lake Lebsko.The activity of the enzymes displayed substantial seasonal fluctuations.The marked impact of pH and salinity on the level of the enzymatic activities was also noticed.
It was demonstrated that significant differences in the abundance of individual physiological groups of bacteria existed among the lakes studied, sampling sites, as well as seasons.Ammonifying, denitrifying and glucose acidifying bacteria constituted the most abundant groups of planktonic and benthic organisms.Bacteria producing hydrogen sulfide and reducing sulfates were rather infrequent.In the case of both water and sediments, microflora of three lakes studied exibited very similar potential ability to carry out the processes of macromolecule degradation.Among bacterai isolated from the two zones, the most abundant were strains hydrolizing proteins, lipids and starch.Only small percentage of strains carried out depolymerization of cellulose.
Mineral composition of water in Roztoka Odrzanska was studied between 1991-1993. The studies showed that the mineral composition of water depends mainly on the magni-tude of the river Odra flow. The increase in mineralisation of Roztoka Odrzanska water was found to be coinciding with the decline of the monthly mean Odra flow below 395 m3?s-1. Specific changes of mineral composition occur in the mixing zone of fresh and saline water. They can be related to coagulation-peptization processes of colloides and sorption processes which use up SO2-, and Mg2+ ions.
Nutrient concentrations and their annual/interannual variability in the Szczecin Lagoon are shaped by variable riverine water/nutrient discharges and bio-geochemical processes in the Lagoon which modify the dissolved/suspended matter introduced. On an interannual scale, nitrate and phosphate concentrations in the Lagoon in 1969-97 displayed quite considerable variability, with maxima of NO3 coinciding with minima of PO4 concentrations. Both NO3 concentrations in the Lagoon and total nitrogen loads showed a strong positive correlation with the water volumes discharged (r = 0.73 and 0.82, respectively). This dependence was much weaker and negative for PO4 (r = - 0.51), and weak and positive for total phosphorus loads (r = 0.35). It would appear, therefore, that in the catchment area of the Oder River, nitrogen sources are mainly diffuse, while phosphorus is derived from point sources. There was a considerable predominance of nitrates in the inorganic nitrogen pool, but the presence of ammonium in large concentrations in winter and summer was also evident. Among the inorganic nutrient species, nitrates exhibited the highest transformation rate into organically bound forms (over 60%) while passing through the Lagoon. The mechanisms responsible for the nutrient transformation patterns in the Lagoon - temperature, in particular - are discussed in the paper. Phytoplankton production in the Lagoon appeared to be phosphorus-limited in spring and nitrogen-limited in summer.
The potential chemical impact of a treated sewage discharged from the ?Gdansk-Wschod? Sewage Treatment Plant to the Gulf of Gdansk was studied. A physical and chemical investigation of the sediments sampled in the area of the planned collector outlet as well as results of an earlier research were the basis for the present paper. A spatial distribution of majority of the studied sediment components shows a distinctive zoning that is clearly due to them being supplied by the Vistula River (Wisla River). This is particular for the mercury, lead, zinc and chromium as well as organic carbon and phosphorus. A distribution of the redox potential shows too a distinctive relation to the Vistula River mouth. Starting a sewage discharge through a new collector located between the two river mouths of the Wisla Smiala and the Wisla Przekop can move westwards the presently observed zoning of increased concentrations of some chemicals. However, most probably such changes will be small and they will not cumulate themselves over time.
The 131-km-long Ulla is one of the most important rivers in the region of Galicia, and flows into the R?a of Arosa, the largest r?a in Galicia. Water, surface sediments and suspended particulate matter were sampled along the Ulla and in its estuary. The grain size fractions below 500 mum, below 63 mum. and, for selected samples, below 2 mum were separated and their contents measured. The concentration of suspended matter, pH and water salinity were also determined. The solid samples were digested with HF+HNO3+HCl and the total concentration of heavy metals (Zn, Pb, Cd, Cu, Ni, Cr, Mn and Fe) analysed by AAS. The sediments and suspended matter in the upper reaches of the river Ulla were found to be enriched with heavy metals: Pb, Cu, Ni, Cr and Zn were present in the sediments in concentrations of up to 68, 300, 357, 1035 and 272 mg kg-1 respectively. The heavy metal concentration in the clay fraction of selected samples is higher than in the below 63 mum fraction. The surface sediments contain heavy metals in concentrations mostly well above what would be expected if these metals had been derived from detrital inputs from soils and weathered granitic rocks, especially in the upper reaches of the Ulla. Of the heavy metals investigated, Zn, Cu, Pb, Cr and Ni are derived from anthropogenic sources.
Species composition of the algae as well as frequencies of their occurrence in a food content of the Chironomus larvae were usually showing a distinctive correlation to the plankton algae rather than to the algae from the mud sediments surface. The main food of the larvae was a filtered phyto-plankton matter decomposed by bacteria. In the reolimnian part of the Lagoon with the sedimentation of the dead phytoplankton restricted by a water-flow, there were poor feeding conditions for the benthos. The main factor that restricted the quantitative growth of the chironomids larvae in that part of the Lagoon was largely because of their feeding on the algae from the sediments.
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