Co-occurrence patterns of some small-bodied freshwater fishes in southwestern France: implications for fish conservation and environmental management

We assessed the influence of environmental variables (elevation, stream order, distance from source, catchment area, slope, stream width, and fish species richness) on the co-occurrence patterns of the minnow, the stone loach, and the gudgeon at the stream system scale. A total of 474 sites were classified according to the seven variables using the Self-Organizing Map (neural network), and three clusters were detected (k-means algorithm). The frequency of the various fish co-occurrence patterns was calculated for each cluster, and general linear modeling was used to specify the conditions that predict the occurrence of each species. Piedmont streams were more likely to support coexisting gudgeon and minnow populations because of higher probabilities of occurrence for both species. The higher co-occurrence frequency for the three species together in headwater streams resulted from lower occurrence frequencies in gudgeon and minnow. Focusing on areas that favor the co-occurrence of species may enhance the effectiveness of conservation projects.     

Biodegradation of technical mixtures of oxyethylenated aliphatic alcohols in an aqueous environment

A study of the biodegradability of nonionogenic surfactants of oxyethylenated n-butyl, isobutyl, n-pentyl and isopentyl alcohols was conducted by modified static test according to International Standard Organization method 9888. Degradation was evaluated by changes in concentrations of individual oligomers, ethylene glycols, carboxylic and dicarboxylic acids. Good biological degradability was found, with a "primary" degradability of 75-98% in 10 days. Obtained results, in agreement with our previous work, proved the dominant proportion of degradative scission in the hydrophile part of surfactant molecule. During biological degradation no significant cumulation of mono- to polyethylene glycols appeared neither that of mono- or dicarboxylic acids, and degradation of these components was not a rate-determining degradation factor.     

Symbiotic efficiency of autochthonous arbuscular mycorrhizal fungus (G. mosseae) and Brevibacillus sp. isolated from cadmium polluted soil under increasing cadmium levels

The effect of inoculation with indigenous naturally occurring microorganisms (an arbuscular mycorrhizal (AM) fungus and rhizosphere bacteria) isolated from a Cd polluted soil was assayed on Trifolium repens growing in soil contaminated with a range of Cd. One of the bacterial isolate showed a marked PGPR effect and was identified as a Brevibacillus sp. Mycorrhizal colonization also enhanced Trifolium growth and N, P, Zn and Ni content and the dually inoculated (AM fungus plus Brevibacillus sp.) plants achieved further growth and nutrition and less Cd concentration, particularly at the highest Cd level. Increasing Cd level in the soil decreased Zn and Pb shoot accumulation. Coinoculation of Brevibacillus sp. and AM fungus increased shoot biomass over single mycorrhizal plants by 18% (at 13.6 mg Cd kg(-1)), 26% (at 33.0 mg Cd kg(-1)) and 35% (at 85.1 mg Cd (kg(1)). In contrast, Cd transfer from soil to plants was substantially reduced and at the highest Cd level Brevibacillus sp. lowered this value by 37.5% in AM plants. Increasing Cd level highly reduced plant mycorrhization and nodulation. Strong positive effect of the bacterium on inocula, are important in plant Cd tolerance and development in Cd polluted soils.     

The comparison of three cyprinid species in terms of heavy metals accumulation in some tissues.

In this study, three cyprinids species (Acanthobrama marmid, Cyprinus carpio, and Chondrostoma regium) from Keban Dam Lake, Elazi?, Turkey, were compared in terms of the levels of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), cobalt (Co), cadmium (Cd), and lead (Pb) in muscle, skin, liver, gonad, and gill tissues. The Co, Cr, Cd, Mn, and Pb were not found in detectable levels in any organs and tissues of any species, according to results obtained by an atomic absorption spectrophotometer. Only Fe, Cu, and Zn were detected in all tissues examined. The results obtained from different cyprinid species were compared to each other and to tolerable values for heavy metals provided from the Food and Agriculture Organization (Rome, Italy) to determine whether these fish species have any risk for human consumption.     

Distribution coefficients (Kd) and desorption rates of 137Cs and 241Am in Black Sea sediments

The distribution coefficients (K_d) and desorption rates of ¹³⁷Cs and ²⁴¹Am radionuclides in bottom sediments at different locations in the Black Sea were studied under laboratory conditions. The K_d values were found to be 500 for ¹³⁷Cs and 3800 for ²⁴¹Am at the steady state and described exponential curves. Rapid uptake of the radionuclides occurred during the initial period and little accumulation happened after four days. The desorption rates for ¹³⁷Cs in different bottom sediments were best described by a three-component exponential model. The desorption half-times of ¹³⁷Cs ranged from 26 to 50 d at the slow components. However, the desorption rate of ²⁴¹Am described one component for all sediment samples and desorption half-time was found to be 75 d. In general, the results showed that the ²⁴¹Am radionuclide is more effectively transferred to bottom sediment and has longer turnover time than ¹³⁷Cs under Black Sea conditions.     

Rapid regional recovery from sulfate and nitrate pollution in streams of the western Czech Republic--comparison to other recovering areas

Hydrochemical changes between 1991 and 2001 were assessed based on two synoptic stream surveys from the 820-km2 region of the Slavkov Forest and surrounding area, western Czech Republic. Marked declines of sulfate, nitrate, chloride, calcium and magnesium in surface waters were compared with other areas of Europe and North America recovering from acidification. Declines of sulfate concentration in the Slavkov Forest (-30 microeq L(-1) yr(-1)) were more dramatic than declines reported from other sites. However, these dramatic declines of strong acid anions did not generate a widespread increase of stream water pH in the Slavkov Forest. Only the most acidic streams experienced a slight increase of pH by 0.5 unit. An unexpected decline of stream water pH occurred in slightly alkaline streams.     

Determinants of male territorial behavior in a Hungarian collared flycatcher population: plumage traits of residents and challengers

In intrasexual conflicts, contestants can rely on relative or absolute size of status badges to mediate aggressive behavior. Most studies focus on the response of focal animals to variation in status badges of their competitors; few have simultaneously considered the traits of both participants under experimental conditions. By simulating territorial intrusions, we tested the importance of two sexual traits [forehead patch size (FPS) and wing patch size (WPS)] in territorial behavior of males in a Hungarian population of the collared flycatcher, Ficedula albicollis. We presented a stimulus male to an unpaired resident male to examine whether the characteristics of the territory owner or those of the challenger were associated with the latency of the first attack of the owner, which is a good predictor of the territorial behavior in general. WPS of the stimulus male was a significant determinant of the latency of the first attack, as males with a larger WPS elicited quicker attacks from the residents than males with a small WPS. From the residents’ perspective, age appeared to influence their territorial behavior, as yearlings had shorter attack latencies than older males. Additionally, latency could be considered an individual-specific attribute because it varied consistently among males, even when the WPS of the stimulus male was controlled, and it was associated with pairing success. Contrary to findings in a Swedish population, FPS seemed to be unimportant in male–male competition in our population, which suggests population differences in the role of the two plumage traits. Our results indicate that in a territorial conflict, the characteristics of both participants are important.     

A 1-Year Study on the Detection of Human Enteric Viruses in New Caledonia

Human enteric viruses occur in high concentrations in wastewater and can contaminate receiving environmental waters. Due to the lack of data on the prevalence of enteric viruses in New Caledonia, the presence and the concentrations of enteric viruses in wastewater and seawater were determined. Untreated wastewater and seawater samples were collected monthly for 1 year from a wastewater treatment plant (WWTP) and from the WWTP’s outlet, located directly on a popular recreational beach. Samples were tested for norovirus genogroups I and II (NoV GI and GII), astroviruses (AsV), sapoviruses (SaV), enteroviruses (EV), hepatitis A viruses (HAV), rotaviruses (RoV), human adenoviruses (HAdV) and human polyomaviruses (HPyV). To support these data, faecal samples from cases of gastroenteritis were tested for the first time for NoV and detected in the population. NoV GI, NoV GII, EV, SaV, HAdV and HPyV were detected in all wastewaters, RoV in 75 % and AsV in 67 %. HAV were not detected in wastewater. Overall, 92 % of seawater samples were positive for at least one virus. HPyV were detected most frequently in 92 % of samples and at concentrations up to 7.7 × 10³ genome copies/L. NoV GI, NoV GII, EV, SaV, RoV and HAdV were found in 33, 66, 41, 33, 16 and 66 % of seawater samples, respectively. AsV were not detected in seawater. This study reports for the first time the presence of NoV and other enteric viruses in New Caledonia and highlights the year-round presence of enteric viruses in the seawater of a popular beach.