Neues vom Ontong-Java-Plateau (Westpazifik)

For the investigation of climatic history for the last 65 million years, several holes were drilled in 1990 on the Ontong Java Plateau by the drilling vessel Joides Resolution, under the auspices of the international Ocean Drilling Program. The Ontong Java Plateau is the largest basalt plateau on earth, and was formed in the Middle Cretaceous. From the core material, seismic reflectors from the overlying sediments can be associated with specific, climate-related oceanic events. For the cyclic sediments of the last 2 million years, high-resolution isotope curves were generated which depict the two dominant Milankovitch cycles with periods of 100 000 and 41000 years.     

Monitoring of iodinated X-ray contrast media in surface water

A monitoring programme was carried out in order to determine iodinated X-ray contrast media (ICM) in the River Danube and to investigate the raw water quality for drinking water production at Langenau waterworks. The study revealed that the maximum concentrations of ICM (over 500 ng l(-1) for diatrizoic acid and iopamidol) were found in 2h-composite samples taken from the downstream of the Ulm/Neu-Ulm metropolitan area. By means of a concentration profile over one month the highest ICM concentrations were observed on weekdays. The extended data evaluation with principal component analysis shows that the upstream and downstream samples had different pattern of variations in ICM concentration and also demonstrates a clear change in ICM composition by the discharge of municipal wastewater. In addition to load profiles of ICM, time-dependent plots of principal component 1 exhibited peaks, indicating a short-term discharge of ICM between the two sampling sites. In conclusion, a point source for ICM contamination between the sampling sites in Ulm upstream and Leipheim downstream seems to be the reasonable explanation for peak ICM concentrations. Due to the observed high variations of ICM concentrations in river, the evaluation of natural waters by means of a single analysis is not representative.     

Spatial and temporal variability of water repellency in a sandy soil contaminated with tar oil and heavy metals

Water repellency can induce preferential flow and thus affect water flow and contaminant transport at hazardous waste sites. Since the spatial patterns of water repellency are mostly unknown, it is problematic to use numerical transport models to predict leachate composition. In this study, the spatial variability of soil water repellency was studied at an industrial site contaminated with tar oil, chromium, copper and arsenic. The persistence of water repellency was assessed by the water drop penetration time (WDPT), and the degree of water repellency was quantified by the ethanol percentage (EP) test. Measurements were made at the soil surface along 3.5-12.1 m long transects at different times between March and October 2002. The spatial variability of WDPT, EP, water content, and organic matter content was quantified by variogram analyses. Both the persistence and the degree of water repellency varied seasonally, with the highest water repellency during the summer months. The correlation lengths of WDPT values ranged between 16 and 406 cm, whereas EP values showed no spatial correlation. For field-moist samples, a critical soil water threshold, below which water repellency prevails, was estimated to be 2.5-4%. For oven dry samples, the WDPT values were dependent on the water content prior to drying. The wide range of correlation lengths and the temporal dynamics of spatial repellency patterns suggest that simulations of solute leaching must consider the spatial and temporal variability of soil hydrophobic properties.     

Tradescantia micronucleus test indicates genotoxic potential of traffic emissions in European cities

Urban atmospheres contain complex mixtures of air pollutants including mutagenic and carcinogenic substances such as benzene, diesel soot, heavy metals and polycyclic aromatic hydrocarbons. In the frame of a European network for the assessment of air quality by the use of bioindicator plants, the Tradescantia micronucleus (Trad-MCN) test was applied to examine the genotoxicity of urban air pollution. Cuttings of Tradescantia clone #4430 were exposed to ambient air at 65 monitoring sites in 10 conurbations employing a standardised methodology. The tests revealed an elevated genotoxic potential mainly at those urban sites which were exposed to severe car traffic emissions. This bioassay proved to be a suitable tool to detect local 'hot spots' of mutagenic air pollution in urban areas. For its use in routine monitoring programmes, however, further standardisation of cultivation and exposure techniques is recommended in order to reduce the variability of results due to varying environmental conditions.     

Light harvesting by wavelength transformation in a symbiotic coral of the Red Sea twilight zone

We report an extraordinary depth range for Leptoseris fragilis (Milne Edwards and Haime), a reef building coral of the Red Sea living in cytosymbiosis with zooxanthellae. The coral harbours an as yet unknown pigment system. We suggest that the heterotrophic host — the coral — provides its photoautotrophic symbionts with additional light. The supplementary light is provided by host pigments which transform light of short wavelengths into suitable wavelengths for photosynthesis, thus amplifying and increasing the transfer of photoassimilates from the zooxanthellae to the host.     

Die ökologische Bewertung von Seeufern in Deutschland

Goal and Scope

Details about the ecological function of lake shores as ecotones between land and lakes are not well-known. These ecotones are also heavily exploited and, in part, considerably changed. Whereas anthropogenic nutrient loading is decreasing, structural changes are increasing. Unfortunately, there is a deficit in methods of evaluation and decision processes.

Main Focus

Even the EU-water framework directive was no remedy for this deficit, as lake shores were included only implicitly. In this article several evaluation methods and their conceptual groundwork are presented. However, these methods were not developed for lake shore research. Therefore, criteria are proposed which could fulfill the specific demands of lake shore assessments. The management of lakes shores should consider structural and biological parameters, and be agreeable to local residents.

Results and Conclusions

In addition to conventional biodiversity methods, the ecology of lake shores could also be represented by a functional food net, for example in benthic invertebrates. But even quantification of biodiversity alone creates many problems. A simple biodiversity index cannot meet all the demands placed on a method of evaluation in complex situations, especially when coupled with additional information on structure, practicability, costs, etc. For these reasons, assessments for future management cannot be based on such an index.

Outlook

A possible approach to include this complexity in assessments is to apply mathematical models and theoretical order concepts.     

Development of a probabilistic blood lead prediction model

A partially probabilistic blood lead prediction model has been developed, based on the US Environmental Protection Agency integrated exposure-uptake-biokinetic blood lead model (IEUBK model). This study translated the IEUBK model into a spreadsheet format. The uptake submodel incorporates uncertainty distributions for exposure and bioavailability parameters. The biokinetic submodel is duplicated with a table incorporating partitioning and decay of lead levels in the body. As a case study, the probabilistic model is applied to a lead exposure scenario involving a former smelter site in Sandy, Utah. The probabilistic model produces less biased estimates of means and standard deviations than the deterministic model. Parameter uncertainty is propagated in the model by the use of Monte Carlo simulation. Thus, sensitivity analysis is possible, and driving variables can be determined.     

Analytische Schnellerkennungsmethoden: Bewertung abzulagernder Abfälle und Kontrolle von Deponien

Rapid test methods have been developed to classify waste. These procedures includes rapid elution and analytical determination methods for the detection of such elements as copper, nickel and zinc. Test kits for matter analysis (with a time requirement of about 30 minutes) have been modified with regard to the matrix waste. A comparison between such rapid testing methods and standard procedures using real samples leads to a similar waste classification. The reduction in time and costs via rapid assay methods allows multiple determinations of wastes to consequently increase the reliability of results from heterogeneous samples. The simple and rapid employment of these tests also makes an “on-site” performance possible.     

Estimating the complexity of bird song by using capture-recapture approaches from community ecology

Repertoire size, the number of unique song or syllable types in the repertoire, is a widely used measure of song complexity in birds, but it is difficult to calculate this exactly in species with large repertoires. A new method of repertoire size estimation applies species richness estimation procedures from community ecology, but such capture-recapture approaches have not been much tested. Here, we establish standardized sampling schemes and estimation procedures using capture-recapture models for syllable repertoires from 18 bird species, and suggest how these may be used to tackle problems of repertoire estimation. Different models, with different assumptions regarding the heterogeneity of the use of syllable types, performed best for different species with different song organizations. For most species, models assuming heterogeneous probability of occurrence of syllables (so-called detection probability) were selected due to the presence of both rare and frequent syllables. Capture-recapture estimates of syllable repertoire size from our small sample did not differ significantly from previous estimates using larger samples of count data. However, the enumeration of syllables in 15 songs yielded significantly lower estimates than previous reports. Hence, heterogeneity in detection probability of syllables should be addressed when estimating repertoire size. This is neglected using simple enumeration procedures, but is taken into account when repertoire size is estimated by appropriate capture-recapture models adjusted for species-specific song organization characteristics. We suggest that such approaches, in combination with standardized sampling, should be applied in species with potentially large repertoire size. On the other hand, in species with small repertoire size and homogenous syllable usage, enumerations may be satisfactory. Although researchers often use repertoire size as a measure of song complexity, listeners to songs are unlikely to count entire repertoires and they may rely on other cues, such as syllable detection probability.Communicated by A. Cockburn