Mechanisms of production and fate of organic phosphorus in the northern Adriatic Sea

In the period from 1980 to 1984 organic phosphorus, nutrients, primary production rates (¹⁴C), chlorophyll a (chl a) standing crops, and basic oceanographic parameters were measured during 23 cruises at six stations in the open waters of the northern Adriatic Sea. These waters are significantly influenced by polluted Po River discharge. Organic phosphorus was correlated with several parameters which characterize phytoplankton activity and organic matter decomposition processes. In the late winter-spring period, organic phosphorus is produced during phytoplankton blooms. It is hypothesized that microzooplankton grazing is the main factor increasing the organic phosphorus concentrations in summer (up to 1.1 mol 1^-1). Fall and winter had much lower values (below 0.3 mol 1^-1) due to remineralization processes and an increased water mass exchange between the northern and central Adriatic regions. The direct contribution of organic phosphorus by freshwater discharge was not found to be significant. The higher organic phosphorus concentrations that can occur in low salinity waters are most likely due to their increased capability to support primary production.     

Mechanisms of copper toxicity in the shore crab,Carcinus maenas

The influence of copper(II)chloride on selected key enzymes and metabolites in intermediary metabolism and the energy charge potential of the hyperregulating shore crab, Carcinus maenas (L.) were investigated. Crabs, collected in Odense Fjord, Denmark between September 1989 and May 1990, were exposed to 10 ppm copper(II)chloride, in 10 ppt salinity seawater at 15°C for up to 1 wk. Hexokinase activity was 77% lower in the posterior gills and 60% lower in the midgut gland than in control crabs. Phosphofructokinase activity was reduced in the midgut gland by 82% but was unaffected in the gills. Pyruvate kinase activity was undetectable in the gills of exposed crabs and reduced by 47% in the midgut gland. Citrate synthase activity was depressed by 30% in the posterior gills and unaffected in other tissues. Copper exposure had no apparent effect on tissue cytochrome c oxidase activity. Chela muscle was the only tissue in which copper exposure did not bring about reductions in the enzyme activities tested. As a result of 1 wk of copper exposure the average lactate level increased by 3.5-fold in haemolymph, 9.3-fold in posterior gills and 6.5-fold in midgut gland. The average glucose level was raised by a factor of 6 in the haemolymph, 3.4 in the posterior gills and 1.2 in the midgut gland. Energy charge potential was at a very high level (ca. 0.9) and was unaffected by copper exposure.     

On the functional extinction of the Passenger Pigeon

The Passenger Pigeon (Ectopistes migratorius) was a social breeder, and it has been suggested that the species experienced functional extinction, defined as a total reproductive failure, prior to its actual extinction in the early years of the 20th century. We applied a novel randomization test based on the relative times of the most recent egg‐ and skin‐specimen sightings (i.e., recorded date of specimen collection) to test for functional extinction. For a total of 6 eggs and 27 skins, the observed significance level was 0.38, which indicated that the species did not become functionally extinct. Thus, proposals to reverse its rapid decline in the late 19th century could have been successful.     

Antibiotic resistance,virulence factors and biofilm formation ability in Escherichia coli strains isolated from chicken meat and wildlife in the Czech Republic

Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals. Consequently, these commensal bacteria might serve as indicator of antimicrobial usage for human and veterinary purposes in the Czech Republic. Further, 46 out of 66 resistant isolates (70%) were able to form biofilm and we found out statistically significant correlation between prevalence of antibiotic resistance and biofilm formation ability. The highest prevalence of antibiotic resistance was observed in weak biofilm producers. Biofilm formation was not statistically associated with any virulence determinant. However, we confirmed the correlation between prevalence of virulence factors and host origin. Chicken isolates possessed more virulence factors (66%), than isolates from wildlife (37%). We can conclude that the potential spread of antibiotic resistance pattern via the food chain is of high concern for public health. Even more, alarming is that E. coli isolates remain pathogenic potential with ability to form biofilm and these bacteria may persist during food processing and consequently lead to greater risks of food contamination.     

Future climate of the Carpathians: climate change hot-spots and implications for ecosystems

Regional Environmental Change - The Carpathians are the largest European mountain range and harbour exceptional biodiversity. However, recent and anticipated changes in climate along with rapid...     

Multi-criteria ranking of copper concentrates according to their quality – An element of environmental management in the vicinity of copper – Smelting complex in Bor,Serbia

The results of multi-criteria ranking of copper concentrates by their quality, according to their content of useful and harmful components, are presented in this paper. Cu, Ag and Au were taken as useful components, while Pb, Zn, As, Cd, Hg, Bi and Sb were considered as harmful with adequate weight parameters. Considering its specific role in copper metallurgy, sulfur in the concentrate was considered in two scenarios. In the first scenario S was considered as a useful and in the other one as a harmful component. The ranking is done by implementing the PROMETHEE/GAIA method with an additional implementation of the special PROMETHEE V method, using the standard limitations of the heavy metals content in the concentrate. In this way, it is possible to perform an optimization of the input charge for the copper extraction from two aspects. The first aspect covers benefits from the content of useful metals, while the second deals with the protection of the environment, considering the content of harmful components of the charge.Using multi-criteria decision making for the sake of ranking the quality of copper concentrates, as described in this paper, could be considered as a contribution to the methodology of forming the market price of this product.     

Mercury distribution around the Spolana chlor-alkali plant (central Bohemia, Czech Republic) after a catastrophic flood, as revealed by bioindicators

The current mercury concentrations in moss Hypnum cupressiforme, in forest floor humus and in oak and pine bark were determined in a 10-km radius around a chlor-alkali plant affected by a flood in 2002. Similar distribution patterns of Hg had accumulated in four bio-indicators, irrespective of different Hg concentrations in the analysed biological matrices. No accumulation of extremely Hg-contaminated materials was found in the flooded parts. The bio-indicators, used alone or in combination, can be recommended for effective and reliable determination of Hg contamination levels around Hg sources.