Assessment of Population Dynamics of Specific Strains in Groundwater Bioaugmentation Experiments by Two Different Molecular Techniques

A set of microcosm experiments was performed to understand the behaviour of special degraders in bioaugmentation experiments. In the experiments the following chlorobenzene degraders were used: the genetically modified Pseudomonas putida F1CC, and the two wild-type strains Pseudomonas putida GJ31 and Pseudomonas aeruginosa RHO1. These strains were used at an initial cell density of 10⁵ cells mL^–1 groundwater which had been spiked with 1,2-dichlorobenzene (1,2-DCB), 1,4-dichlorobenzene (1,4-DCB) and, as main contaminant, chlorobenzene (CB). The population dynamics and behaviour of the three special degraders within the groundwater microcosms were studied by single-strand conformation polymorphism (SSCP) analysis of 16S rDNA fragments amplified from directly extracted community DNA and fluorescent in situ hybridization (FISH) with species-specific probes. RHO1 disappeared after 4 days as detected by FISH in contrast to SSCP-detection where RHO1 could be found during the whole incubation time. Whereas GEM F1CC and wild-type strain GJ31 survived the whole incubation for 20 days. With both methods we were able to detect all strains with high specificity among the indigenous microbial community. The data sets obtained from SSCP analysis and FISH were highly correlated. Specific band intensity within the SSCPfingerprints and the cell counts determined by FISH gave a quantitative overview about the introduced strains.     

Responses to playback of whistle songs and normal songs in male nightingales: effects of song category, whistle pitch, and distance

In most species of song birds, males develop song repertoires of several different songs. Among this variety, different songs may be used differently in communication and, thus, may have different functions. Here we studied vocal responses to playback of structurally different songs in male territorial nightingales (Luscinia megarhynchos). Nightingales have enormous vocal repertoires of about 200 song types. Among these songs, one category, whistle songs, sticks out syntactically and acoustically. Here we tested whether or not male nightingales match whistle songs with whistle songs and, if so, whether they also match the pitch of the broadcast whistles. Furthermore, we also tested if nightingales treat whistle songs as a separate category of songs. We conducted interactive playback experiments on nocturnal song in which each male received three playback treatments that differed in the number of whistle songs broadcast. Males responded differently during playbacks by singing significantly more whistle songs when the playback tapes contained many whistle songs than when they contained no whistle songs. Males also frequently matched the pitch of the broadcast whistle songs. In contrast to responses during playback, after the playback terminated males sang more whistle songs when no whistle songs were broadcast than when many whistle songs were broadcast. These findings suggest that whistle songs have a specific signal value and that nightingales treat them as a special song category. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00265-002-0511-1.     

Die Wirkung von Photooxidantien auf Sommerweizen (Triticum aestivum L. Star)

The effect of short-time fumigation with the peroxidic photooxidants ozone, peroxyacetyl nitrate (PAN), and hydrogen peroxide (H₂O₂) on the gas exchange of wheat leaves was investigated. Two types of experiments are to be distinguished:

1. Fumigation is carried out at atmospheric CO₂ partial pressure (350 μbar) and the assimilation and transpiration rates are followed simultaneously.
2. The alteration of CO₂-response curves by fumigation is determined; from this, characteristic photosynthetic parameters can be calculated.

With this method, statements about the reaction of both photosynthesis as a whole and specific reaction sites within the most important photosynthetic processes are possible. Ozone in concentrations of 260–280 ppb causes a primary perturbation of the photosynthetic apparatus, whereby the carboxylation rate is affected to nearly the same extent as the electron-transport rate.PAN (120 ppb) causes a reduction in the assimilation rate, primarily due to the closing of the stomata. H₂O₂ affects the gas exchange only in concentrations of above 1 ppm, whereby the reduction of the assimilation rate represents an almost pure stomatal effect. All three fumigants cause an increase in the respiration rate, which may point to an activation of detoxification and repair mechanisms.     

Free phosphine from the anaerobic biosphere

The possible liberation of highly toxic and mutagenic phosphine from putrefying media raises the question of its significance as a problem of hygiene. Free phosphine was established by gas chromatography as a universal trace component in gas emitted from the anaerobic biosphere. Sources of phosphine include landfills, compost processing, sewage sludge, animal slurry and river sediments. We detected maximum concentrations in the order of 20 ppb(v/v).     

Upscaling of Environmental Information: Support of Land-Use Management Decisions by Spatio-Temporal Regionalization Approaches

This article presents several case studies in southwest Germany, which aimed to support land use management decisions by a process-oriented statistical upscaling of point-related environmental monitoring data to the landscape scale. When techniques of data subsetting were used in a sensible way and corresponding to the appropriate scale for the evaluation envisaged, multiple linear regression offered a data mining technique which was able to spatially predict relatively complex environmental patterns with parsimonious, interpretable and accurate models, whereby different evaluation scales were best represented by different DTM resolutions. Scenario models based upon the regression formulas were a valuable tool for visualizing management options and evaluating management impacts (tree species selection) on soil functions (carbon storage), which qualifies the presented methodology as a useful aid in decision making. Such upscaling techniques may be used for forecasting long-term effects of ecosystem management, but they provided no information on temporal dynamics. Therefore, time trends of point information on soil solution data were scaled by linking them to soil chemical data which was available in higher spatial resolution, using both statistical and process-oriented methods.     

Role of protein, amino acids, and enzyme activity on odor production from anaerobically digested and dewatered biosolids.

The main objective of this research was to test the hypothesis that bioavailable protein and, more specifically, the sulfur-containing amino acids within the protein, can be degraded by proteolytic enzymes to produce odor-causing compounds--mainly volatile sulfur compounds (VSCs)--during biosolids storage. To achieve these objectives, samples of digester effluent and cake solids were collected at 11 different wastewater treatment plants in North America, and the samples were analyzed for protein and amino acid content and general protein-degrading enzyme activity. At the same time, cake samples were stored using headspace bottles, the concentration of VSCs were measured using gas chromatography, and olfactometry measurements were made by a trained odor panel. The results showed that the bound cake protein content and methionine content was well-correlated with VSC production and the detection threshold measured by the odor panel.     

Antibiotika (Ivermectin, Monensin) und endokrine Umweltchemikalien (nonylphenol, Ethinylöstradiol) im Boden

The influence of four synthetic chemicals (nonylphenol, ethynyl-estradiol, ivermectin, monesin) on the biomass and on the microbial activity was studied in a laboratory experiment using a typical luvisol derived from loess. The polyether antibiotic monensin, the antiparasitic agent ivermectin and the two environmental chemicals with endocrine effects nonylphenol and ethynylestradiol were chosen because of their toxicity to different organisms and known biological activity. These agents may enter the soil together with sewage sludge or manure. To date, however, the effects on soil have hardly been studied. Selected microbial methods revealed in part very significant effects on the microbial biomass and microbial activity during constant physical (15°C, 50% water holding capicity) and chemical conditions (pH, C_org) 1, 14 and 42 days after contamination.     

Sulfuric acid at workplaces--applicability of the new Indicative Occupational Exposure Limit Value (IOELV) to thoracic particles

Until 2009, the limit values for airborne sulfuric acid in Europe were based on the inhalable particle fraction (e.g. MAK (Maximum allowed concentration at workplace) value 0.1 mg m(-3) as the inhalable fraction). With the publication of the Commission Directive 2009/161/EU, an Indicative Occupational Exposure Limit Value (IOELV) of 0.05 mg m(-3) for sulfuric acid aerosols was based for the first time on the thoracic particle fraction. To permit a comparison of the measured values for the inhalable fraction with those of the thoracic fraction and to quantify the thoracic fraction, a cyclone was fabricated out of sulfuric-acid-resistant stainless steel that achieves suitable collection characteristics (PM(10)) at a flow rate of 5.34 L min(-1). 49 measurements were carried out in parallel in 21 companies. At concentrations well below the IOELV, there is little difference between the thoracic and inhalable particle concentrations. At higher concentrations (>0.1 mg m(-3) inhalable aerosol), larger droplets have a marked effect on the measured values and the thoracic fraction accounts for only 32.1 ± 12.5% of the inhalable fraction. The EU's IOELV and the proposal of the MAK Commission therefore provide a comparable level of protection. In the transposition of the IOELV into national law, an air limit of 0.1 mg m(-3) could therefore be implemented for the inhalable fraction.     

Cycling of volatile organic sulfur compounds in anaerobically digested biosolids and its implications for odors.

The objectives of this research were to elucidate the mechanisms for production and degradation of volatile organic sulfur compounds (VOSCs), key odor causing compounds produced by biosolids. These compounds included methanethiol (MT), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS). A series of experiments were used to probe various pathways hypothesized to produce and degrade these VOSCs. The production of MT was found to mainly occur from degradation of methionine and the methylation of hydrogen sulfide. DMS was formed through the methylation of MT. DMDS was formed by MT oxidation. All three of the VOSCs were readily degraded by methanogens and a cyclic pathway was proposed to describe the production and degradation of VOSCs. The research demonstrated that the main source of VOSCs was the biodegradation of protein within the biosolids and the results provided a framework for understanding the production of odor from anaerobically digested sludges before and after dewatering.