Southeast Germany Research Articles

Short-term effects of temperature enhancement on growth and reproduction of alpine grassland species

In order to study the effects of temperature enhancement on alpine calcareous grassland species, a warming experiment was carried out in the Berchtesgaden National Park (Southeast Germany, Northern Calcareous Alps) between 2002 and 2004. The study was conducted in stands of the Carex sempervirens and the Carex firma communities; the two most widespread grassland types in the alpine zone of the Northern Calcareous Alps. The temperature of the vegetation stand and the upper soil was passively enhanced using open top chambers (OTCs). The construction of the OTCs was appropriate since temperature was clearly increased while water conditions (humidity, soil water content) were not changed. By comparing manipulated (temperature enhancement) with non-manipulated plots, the effects of warming on growth and reproduction of selected key species were studied. To test if vegetation response to temperature enhancement is at least partly due to increases in nutrient availability, soil solution concentrations of nitrate and ammonium were analysed. We found that most of the studied plant species are sensitive to temperature enhancement. Growth and/or reproduction of 12 of the 14 studied species were significantly stimulated by warming. Only two species showed no response; none of the species experienced decreases in growth or reproduction. Dwarf shrubs and graminoids showed a stronger response than herbaceous perennials. A significant effect of warming on nutrient availability could not be detected. The observed response of vegetation is therefore mainly caused by direct and not by indirect temperature effects. Um die Auswirkungen einer Temperaturerhöhung auf die Vegetation alpiner Kalk-Magerrasen zu untersuchen, wurde im Bereich des Nationalparks Berchtesgaden (Nördliche Kalkalpen, SO-Deutschland) zwischen 2002 und 2004 ein Erwärmungsexperiment durchgeführt. Als Vegetationstypen wurden der Horstseggenrasen und der Polsterseggenrasen gewählt, da diese die flächenmäßig bedeutsamsten Vegetationseinheiten der alpinen Kalk-Magerrasen darstellen. Die Umgebungstemperatur der Pflanzen und die Oberbodentemperatur wurden mittels Open Top Chambers (OTCs) passiv erhöht. Die Konstruktion der OTCs erwies sich als günstig, da sie die Temperatur deutlich erhöhte, nicht aber den Wasserhaushalt (Luftfeuchtigkeit, Bodenwassergehalt) der Bestände änderte. Durch einen Vergleich von erwärmten mit nicht erwärmten Flächen wurden die Auswirkungen einer Temperaturerhöhung auf Wachstum und Reproduktion ausgewählter Schlüssel-Arten untersucht. Bodenkundliche Untersuchungen sollten klären, ob neben direkten auch indirekte Temperatureffekte (verbesserte Nährstoffverfügbarkeit) für die Vegetation eine Rolle spielen. Die vorliegende Untersuchung zeigt, dass Pflanzenarten alpiner Kalk-Magerrasen sensibel auf eine experimentell induzierte Temperaturerhöhung reagieren. Wachstum und/oder Reproduktion von 12 der 14 untersuchten Arten wurden durch die Erwärmung stimuliert. Nur zwei Arten reagierten nicht, keine einzige Art zeigte eine negative Reaktion. Zwergsträucher und Grasartige regierten insgesamt stärker auf die Temperaturerhöhung als krautige Arten. Signifikante Effekte der Erwärmung auf die Nährstofffreisetzung konnten nicht nachgewiesen werden. Die aufgezeigten Reaktionen der Vegetation beruhen daher offenbar auf direkten und nicht auf indirekten Temperatureffekten.

Larval trematodes (Digenea) of the great pond snail,Lymnaea stagnalis(L.), (Gastropoda, Pulmonata) in Central Europe: a survey of species and key to their identification

A survey of cercariae and metacercariae (Trematoda, Digenea) from the great pond snail (Lymnaea stagnalis) in Central Europe (Austria, Czech Republic, South-East Germany, Poland and Slovak Republic) is presented, based on a study of 3,628 snails examined from 1998 to 2005. A total of 953 (26.3%) L. stagnalis were infected with 24 trematode species comprising 19 species of cercariae and 11 species of metacercariae (six species occurred both as cercarie and metacercarie) of eight families. The dominant cercariae were those of Opisthioglyphe ranae (159 hosts infected), Plagiorchis elegans (141) (both family Plagiorchiidae) and Echinoparyphium aconiatum (153) (Echinostomatidae); 14 double infections were found. The most frequent metacercariae were those of Neoglyphe locellus (71) (Omphalometridae), E. aconiatum (66), Echinostoma sp. (59) and Moliniella anceps (48) (Echinostomatidae). In the previous studies carried out in Central Europe, a very similar spectrum of nine trematode families of 22 cercariae determined to species level and 43 types of cercariae reported under generic or provisional names, which can be in many cases conspecific with the previous taxa, were found. A simple key to identification of cercariae and metacercariae, together with their illustrations, is provided.

Biomass, morphology and nutrient contents of fine roots in four Norway spruce stands

Fine root systems may respond to soil chemical conditions, but contrasting results have been obtained from field studies in non-manipulated forests with distinct soil chemical properties. We investigated biomass, necromass, live/dead ratios, morphology and nutrient concentrations of fine roots (<2 mm) in four mature Norway spruce (Picea abies [L.] Karst.) stands of south-east Germany, encompassing variations in soil chemical properties and climate. All stands were established on acidic soils (pH (CaCl2) range 2.8–3.8 in the humus layer), two of the four stands had molar ratios in soil solution below 1 and one of the four stands had received a liming treatment 22 years before the study. Soil cores down to 40 cm mineral soil depth were taken in autumn and separated into four fractions: humus layer, 0–10 cm, 10–20 cm and 20–40 cm. We found no indications of negative effects of N availability on fine root properties despite large variations in inorganic N seepage fluxes (4–34 kg N ha−1 yr−1), suggesting that the variation in N deposition between 17 and 26 kg N ha−1 yr−1 does not affect the fine root system of Norway spruce. Fine root biomass was largest in the humus layer and increased with the amount of organic matter stored in the humus layer, indicating that the vertical pattern of fine roots is largely affected by the thickness of this horizon. Only two stands showed significant differences in fine root biomass of the mineral soil which can be explained by differences in soil chemical conditions. The stand with the lowest total biomass had the lowest Ca/Al ratio of 0.1 in seepage, however, Al, Ca, Mg and K concentrations of fine roots were not different among the stands. The Ca/Al ratio in seepage might be a less reliable stress parameter because another stand also had Ca/Al ratios in seepage far below the critical value of 1.0 without any signs of fine root damages. Large differences in the live/dead ratio were positively correlated with the Mn concentration of live fine roots from the mineral soil. This relationship was attributed to faster decay of dead fine roots because Mn is known as an essential element of lignin degrading enzymes. It is questionable if the live/dead ratio can be used as a vitality parameter of fine roots since both longevity of fine roots and decay of root litter may affect this parameter. Morphological properties were different in the humus layer of one stand that was limed in 1983, indicating that a single lime dose of 3–4 Mg ha−1 has a long-lasting effect on fine root architecture of Norway spruce. Almost no differences were found in morphological properties in the mineral soil among the stands, but vertical patterns were apparently different. Two stands with high base saturation in the subsoil showed a vertical decrease in specific root length and specific root tip density whereas the other two stands showed an opposite pattern or no effect. Our results suggest that proliferation of fine roots increased with decreasing base saturation in the subsoil of Norway spruce stands.

Extraordinary snow accumulations over parts of central Europe during the winter of 2005/06 and weather‐related hazards

During the winter of 2005/06, record-breaking snow accumulations were observed in many locations in south-east Germany, large parts of Austria and in the low mountain ranges along the Czech/German as well as Czech/Austrian borders. In the lowlands, low mountain ranges and eastern Alpine valleys of the above-mentioned study area, the snow mantle reached its maximum depth in early to mid-March, with many stations reporting snow depths between 40 and 60 cm in the morning hours of 7 March 2006 (Figure 1), with a few readings of more than 100 cm, e.g. Lunz am See 139 cm (Eastern Alps, Austria, altitude of 615 m above sea-level (a.s.l.)) and Zinnwald-Georgenfeld 150 cm (Erz Mountains, Germany, 882 m a.s.l.). Shortly after this date, widespread snow depths of more than 100 cm were also observed in the Bavarian and Bohemian Forests and the Austrian Forest Quarter. The picture taken at Neureichenau (Bohemian Forest, Germany) on 12 March 2006 gives a good impression of the landscape buried under the deep snow (Figure 2). As seen in the picture, local residents had to remove the snow from the roofs of their houses to avoid collapse. The winter of 2005/06 was not only notable in terms of the snow depth at the end of the winter season, but also in terms of snow-cover duration and intermittent heavy snowfall events in the low-lying areas of the study region. Among the most momentous weather-related hazards were the collapse of several roofs under the heavy weight of the snow. For example, the breakdown of the dome of an ice skating hall at Bad Reichenhall (Germany) on 2 January killed 15 people and injured over 50. As many winters in the last two decades were unusually mild and, consequently, marked by a poor snow cover, the winter of 2005/06 was perceived by the local residents as being extremely snowy, cold and long. People will commemorate the winter of 2005/06 as being the severest in decades; at some locations the severest within living memory. In the present contribution, we will highlight that from the climatological standpoint the winter was neither unusually wet nor cold, but characterised by the absence of significant thawing episodes. We will relate this to the anomalous frequency and persistence of two particular circulation weather types. This article will also give a more detailed account of the weatherrelated hazards and will briefly discuss if this type of extreme weather is likely to be expected more frequently in the future. For these aspects, the winter period is defined as the time from the beginning of October to the end of March. The winter of 2005/06

First Comparison of Array-Derived Rotational Ground Motions with Direct Ring Laser Measurements

Recently, ring laser technology has provided the first consistent obser- vations of rotational ground motions around a vertical axis induced by earthquakes. Consistent, in this context, implies that the observed waveforms and amplitudes are compatible with collocated recordings of translational ground motions. In partic- ular, transverse accelerations should be in phase with rotation rate and their ratio proportional to local horizontal phase velocity assuming plane-wave propagation. The ring laser installed at the Fundamentalstation Wettzell in the Bavarian Forest, Southeast Germany, is recording the rotation rate around a vertical axis, theoretically a linear combination of the space derivatives of the horizontal components of motion. This suggests that, in principle, rotation can be derived from seismic-array experi- ments by finite differencing. This has been attempted previously in several studies; however, the accuracy of these observations could never be tested in the absence of direct measurements. We installed a double cross-shaped array of nine stations from December 2003 to March 2004 around the ring laser instrument and observed several large earthquakes on both the ring laser and the seismic array. Here we present for the first time a comparison of array-derived rotations with direct measurements of rotations for ground motions induced by the M 6.3 Al Hoceima, Morocco, earthquake of 24 February 2004. With complete 3D synthetic seismograms calculated for this event we show that even low levels of noise may considerably influence the accuracy of the array-derived rotations when the minimum number of required stations (three) is used. Nevertheless, when using all nine stations, the overall fit between direct and array-derived measurements is surprisingly good (maximum correlation coefficient of 0.94).

Impacts of Snowmelt on Peak Flows in a Forest Watershed

Using data of long-term observations at three gauging stations and one climatic station in a forest region in southeast Germany, the impacts of snowmelt on peak flow have been investigated in this paper. Results show that the major climatic feature was found to be a precipitation maximum during the hydrological summer, and the major hydrological feature was a discharge maximum during the hydrological winter. Empirical equations describing snow depth and snow water equivalent for the studied climatic station have been developed for both snow accumulation period and ablation period. Through introducing snowmelt-rainfall depth as a new variable, the present work investigates the simultaneous occurrence of snowmelt and rainfall on snow cover, assesses the characteristics of runoff including peak flows, calculates the runoff from the snowmelt and rainfall. A hydrological model has been applied to generate hydrographs resulted from snowmelt and rainfall-on-snow.

Larval trematodes in freshwater molluscs from the Elbe to Danube rivers (Southeast Germany): before and today

Studies on life cycles of trematodes have a long tradition in Germany; (Odening 1978) listed a total of 177 trematodes, which can potentially complete their life cycles in German inland waters. However, almost no recent data on the occurrence of larval stages in molluscs are available. Therefore, a survey of trematodes in Southeast Germany was carried out in 2004. A total of 31 species of ten families (29 species of cercariae, seven species of metacercariae, and five species found of both) were found in 311 (4.9%) molluscs of 15 species. The dominant cercariae were Plagiorchis elegans, Echinoparyphium aconiatum, Opisthioglyphe ranae, and Diplostomum pseudospathaceum. Echinoparyphium pseudorecurvatum is reported, for the first time, under its valid scientific name from Germany. In previous studies from the same region, 88 species of cercariae of 16 families were found in 19 species of molluscs (52 cercariae with valid names and 36 not identified to species level). It is proposed that there is still a very similar spectrum of the most common species of cercariae typical for Central Europe as found 20, but also 100-150 years ago.

A new Puumala hantavirus subtype in rodents associated with an outbreak of Nephropathia epidemica in South-East Germany in 2004

A micro-epidemic of hantavirus infections occurred in Lower Bavaria, South-East Germany, starting in April 2004. While only three cases were registered from 2001 to 2003, a dramatically increased number of clinically apparent human hantavirus infections (n=38) was observed in 2004, plus seven additional cases by June 2005. To determine the reservoir responsible for the infections, a total of 43 rodents were trapped in Lower Bavaria. Serological and genetic investigations revealed that Puumala virus (PUUV) is dominant in the local population of bank voles. Partial PUUV S segment nucleotide sequences originating from bank voles at four different trapping sites in Lower Bavaria showed a low divergence (up to 3.1%). This is contrasted by a nucleotide sequence divergence of 14-16% to PUUV strains detected in Belgium, France, Slovakia or North-Western Germany. PUUV sequences from bank voles in Lower Bavaria represent a new PUUV subtype which seems to be responsible for the observed increase of human hantavirus infections in 2004-2005.

Investigation of coupled hydraulic–geomechanical processes at the KTB site: pressure‐dependent characteristics of a long‐term pump test and elastic interpretation using a geomechanical facies model

AbstractThe German Continental Deep Drilling Program comprising a pilot borehole down to 4000 m and a main borehole down to 9101 m in southeast Germany (KTB) is continuing to provide a unique opportunity for the identification of important factors and processes in deep‐seated fluid and energy transfer. In situ stress conditions significantly impact flow, transport and exchange characteristics of fracture networks that dominate the permeability of crystalline reservoir rocks. In this paper, several scales of information are combined to present a fully three‐dimensional hydraulic finite element model of the principal KTB fault zones, and linked to a geomechanical model describing the alteration of the hydraulic parameters with stress changes caused by fluid extraction. The concept of geomechanical facies is introduced to define and characterize architectural elements in the subsurface system. Evaluation of a long‐term pump test in the KTB pilot hole, June 2002–July 2003, coupled with a geomechanical model gives an insight into some of the elastic and nonelastic processes controlling hydraulic transport in the basement rocks. Trends in the decline of the permeability and the degree of storage in the system could only partially be explained by elastic processes, clearly indicating the importance of nonelastic processes. A number of inelastic processes are suggested as areas for further research.

The Reference Index Method for the Macrophyte-BasedAssessment of Rivers - a Contribution to the Implementationof the European Water Framework Directive in Germany

The European Water Framework Directive requires ecological status classification and monitoring of surface and ground waters using biological indicators. To act as a component of the “Macrophytes and Phytobenthos” biological quality element, as demanded by the Directive, a macrophyte-based assessment system was developed for application in river site types in Germany. Macrophyte abundance data were collected from 262 sites in 202 rivers. Seven biocoenotic river site types were established using differences in characteristic macrophyte communities reflecting ecoregion, channel width, water depth, current velocity, water hardness, and ground water influence. For four of these river site types, a macrophyte assessment system was developed, for the remaining three river site types data were insufficient for developing an assessment system. Ecological status classification of river sites is based on the calculation of a Reference Index value, in some cases supplemented by additional vegetation criteria. The Reference Index quantifies the deviation of species composition and abundance from reference conditions and classifies sites as one of the five possible ecological quality classes specified in the Directive. The assessment of long river stretches with changing river site types along its course is discussed based on an example from the Forstinninger Sempt River, southeast Germany. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Proxiandrena subgen. nov. and revision of the Andrena proxima group in the western and central Palaearctic Region (Hymenoptera, Apidae)

The former Andrena proxima group is revised for the western and central Palaearctic Region. Proxiandrena subgen. nov. is described for the here treated species with Andrena proxima as type species. Proxiandrena includes 5valid species, which had been treated as subspecies of Andrena proxima s. 1. before: Andrena ampla Wamcke in Morocco, Spain, southern France, the western Alpes, and - separated from this area - in Central Asia north of Turkmenistan; Andrena alutacea Stoeckhert with a range from southeast Germany and eastern Switzerland to the eastern Mediterranean area and Turkmenistan; Andrena aspericollis Perez from Algeria; Andrena bernicla Warncke from Turkey; Andrena proxima (Kirby) from Central Europe and Italy. A key to the species and diagnostic characters are given and distribution of the species is discussed. The female of A. bernicla is unknown and its status as a species remains doubtfull.

A 500 year dendroclimatic reconstruction of spring-summer precipitation from the lower Bavarian Forest region, Germany

This paper presents a 500 year March–August precipitation reconstruction for the Bavarian Forest region of southeast Germany based on a composite, well-replicated data set of 676 living and historical tree-ring width series from Norway spruce. Two versions of the chronology are developed. The cubic smoothing spline (SPL) chronology, standardized with a fixed 80 year spline function, retains decadal and higher frequency variation. The regional curve standardization (RCS) chronology uses regional curve standardization to retain additional lower frequency variation from the same data. Calibration (1879–1978) of these chronologies with March–August precipitation indicates they explain 40% (SPL) and 34% (RCS) of the variability in the instrumental precipitation record. The SPL reconstruction models the highfrequency variation better, whereas the RCS reconstruction tracks the low-frequency trends more robustly. It suggests that spring–summer precipitation was above the long-term average for the periods 1730–1810 and 1870–2000, about average between 1560 and 1610 and that significantly drier periods occurred during 1510–60, 1610–35, 1660–1730 and 1830–70. The low-frequency trends of the RCS reconstruction during the 19th century were verified by comparison with a regional precipitation series derived from 14 long precipitation records from central Europe. Better verification results were obtained using the original (non-homogenized) records over this interval. These results suggest that some low-frequency variability may have been removed during correction of these early records. Periods of synchronous decadal variability were observed between the SPL series and independent dendroclimatic reconstructions from central Europe. The RCS reconstruction is the first dendroclimatic precipitation reconstruction in Europe to capture low-frequency information. These long-term trends, however, are difficult to verify owing to the paucity of other proxy precipitation records in central Europe that portray low-frequency information. Further verification and testing of the RCS reconstruction will require the development of additional reconstructions from tree-rings (or other proxy data series) that similarly target low-frequency variability. Copyright  2005 Royal Meteorological Society.

P wave material anisotropy of a tectono‐metamorphic terrane: An active source seismic experiment at the KTB super‐deep drill hole, southeast Germany

An active‐source seismic experiment at the KTB deep drill hole in southeast Germany reveals seismic P wave anisotropy to exist within a tectono‐metamorphic sub‐terrane of the crystalline Bohemian massif. The experiment used multi‐azimuth vertical seismic profiling whereby downhole sensors recorded surface seismic Vibroseis sources located along six 7.5‐km radial profiles emanating from the borehole location. Representative bulk anisotropic P wave velocities of the upper crust were derived from this seismic data and compared with predictions of velocity and anisotropy based on petrophysical laboratory measurements and geological information. We show that azimuth and inclination behavior of the observed anisotropy is consistent with characterization of the geology surrounding the borehole as a coherent regional block containing pervasive highly tilted foliation. This seismic anisotropy can be explained by “intrinsic” material properties associated with the well‐developed foliation fabrics.

Lightning detection with 3‐D discrimination of intracloud and cloud‐to‐ground discharges

A new technique has been developed to operate spatially extended VLF/LF lightning detection networks in a pseudo 3‐D mode in order to facilitate discrimination of intra‐cloud and cloud‐to‐ground lightning. Time‐of‐arrival measurements are carried out with high precision to distinguish VLF/LF‐emission regions of lightning discharges in higher altitudes and near ground, respectively. This is accomplished by utilizing deviations of arrival times measured at sensor stations close to lightning events as compared to arrival times expected on the basis of 2‐D propagation paths. Successful functioning of the method in networks of common dimensions requires that both signal processing and event time tagging is achieved with an accuracy level of about 1 μs. Results are presented from a new network which has been operating continuously since May 2003 and covers southeast Germany in an area of approximately 300 × 400 km. VLF/LF source emission heights of ∼5–15 km have been identified.

Utilising historical tree-ring data for dendroclimatology: A case study from the Bavarian Forest, Germany

Summary Although there are abundant historical tree-ring (TR) data available in Europe, these data have rarely been used for dendroclimatic reconstruction. Dendro-historical dating is possible because of a strong common signal in the TR data, which, if consistent over large areas, must represent a common climatic forcing upon growth. The most commonly cited limitations to the use of historical TR data for climate reconstructions are (1) mixed climate signals within the living TR data used to crossdate the historical TR data (e. g. European Oak) and (2) the unknown provenance and/or site ecology of the historical wood. In addition, as historical timbers were often taken from relatively young trees, they may have a different climate response from the mature living trees used for calibration studies. The short mean segment length of the historical timbers may also limit the potential to recover low frequency growth trends from these series. In this study, we address these issues using a well-replicated TR data-set comprised of 678 living and historical TR width series of Norway spruce (Picea abies (L.) Karst) sampled in the Lower Bavarian Forest region in south-east Germany. The historical TR series were collected from 40 buildings in towns along the Danube River. Local knowledge suggests that almost all wood used for construction prior to the 20th century had a local origin. The historical spruce TR series correlate with living spruce chronologies from sites located below 700 m, but do not correlate with spruce chronologies from above 1050m. Comparison of the statistical characteristics of chronologies from historical timbers (e. g. ring-width, mean sensitivity and correlation with high elevation spruce chronologies) with those from living trees at low elevation sites indicated that the timbers were derived from ecologically similar, low elevation sites. As RW series of these living-tree sites contain a strong spring/summer precipitation signal, it is suggested that the historical TR data are similarly climate-sensitive. Differences in age-related response to climate were addressed by comparing the response of TR chronologies composed of trees 110 years with spring/summer precipitation. Results from a moving window regression procedure indicate no significant difference in the climate response of these two chronologies. The segment length problem was examined by dividing the 678 TR series into 3 age groups and applying regional curve standardisation. We demonstrate that multi-centennial trends can be captured from these data even when sample lengths of

La formation professionnelle en Allemagne : une coopération réussie avec les entreprises et un atout pour le développement local. L'exemple de la Fachhochschule Furtwangen en Forêt-Noire (Vocational training in Germany : a successful partnership with business and an asset for local development. A case study of Black Forest based-Fachhochschule Furtwangen)

This paper questions the impact that training institutions can have on a region 's economic development. First, it presents three different models of German vocational training. Then the paper focuses on the Fachhochschule Furtwangen, based in the uplands of the Black Forest, a rural district of south-east Germany, which provides a good example of a positive partnership between training institutions and the world of work. High quality training combined with a pivotal position among SMEs in research projects have made it a key factor for the location of more high tech and innovative companies than elsewhere.

Progressive Hyperpigmentation and Generalized Lentiginosis without Associated Systemic Symptoms: a Rare Hereditary Pigmentation Disorder in South-East Germany

Familial progressive hyperpigmentation is rarely described in the literature. We report on five patients from three different families presenting with a peculiar progressive pigmentary disorder. The patients show a progressive diffuse, partly blotchy, hyperpigmentation, intermixed with scattered small hypopigmented macules, a few large hypopigmented areas, occasional café-au-lait spots and, most remarkably, a generalized lentiginosis. Histology revealed different degrees of basal layer hyperpigmentation and pigment incontinence, also in the spots appearing hypopigmented. Ultrastructural analysis showed a normal mode of Caucasian-like melanogenesis with varying content of regular melanosome complexes within the keratinocytes. All families are clustered in a small area around the town of Teublitz in south-east Germany with about 20,000 inhabitants, suggesting a genetic founder effect. Pedigree analysis is compatible with an autosomal dominant mode of inheritance with variable penetrance. Only a few similar, but not identical, cases have been reported in the past. This cluster of cases may therefore represent a rare and perhaps novel variant of a familial progressive disorder of hyperpigmentation.

Envionmental applications of airborne radiometric surveys

Airborne gamma-ray measurements, primarily developed for uranium exploration (e.g. Bristow 1983), have many applications in environmental monitoring and geological mapping (e.g. IAEA 1991; Jaques et al.1997; Wilford et al. 1997). For example, they have been used to map radioactive fallout from nuclear accidents (e.g. Mellander 1989) and contaminant plumes from power plants (e.g. Rangelov et al. 1993) as well as monitoring the impact of uranium mining. Airborne measurements can be used for quick and effective mapping of large areas. Although the gamma-ray measurements record variations in the radioactivity of a relatively shallow surface layer (c. 0.3 m), the results are useful for both regional and targeted surveys. The results are normally presented as total gamma activity and as equivalent ground concentrations of uranium, thorium, potassium and other radionuclides (e.g. 137Cs) or as ratios (including ternary K, U, Th plots). Methods have been developed to separate natural and man-made radioactivity. This paper presents some examples of environmental applications of airborne gamma-ray surveys from Germany and the UK. In both cases, the results of multisensor (radiometric, electromagnetic and magnetic) airborne surveys are validated by ground measurements and sampling. The AERA project (Assessment of environmental risks by airborne geophysical techniques validated by geophysical field measurements) was an EC-funded project in south-east Germany, coordinated by the Geological Survey of Finland (GTK) (Gaál et al. 2001). A 1100 km2 site in the Zwickau area of Saxony was selected because of its extensive mining and industrial activities over several centuries. Uranium, black coal and nickel mining and smelting, military activities, modern heavy industry, and industrial and domestic waste have caused considerable environmental impacts. The HiRES-1 survey of central Britain was carried out to assess a range of environmental and resource applications of airborne survey data. The 14000 km2 area surveyed encompasses a wide range of rock and soil types. The area includes many urban centres and has a long history of extractive and manufacturing industry. There are regions with relatively high indoor radon levels and areas contaminated by fallout from nuclear weapons testing, the Chernobyl accident and discharges from the Sellafield nuclear fuel reprocessing plant. Small targets within the HiRES-1 area were flown as part of a collaborative GTK-BGS (British Geological Survey) project to investigate specific sites in more detail. These included landfills, colliery spoil heaps and gravel workings used for power station fly ash disposal. Although a multisensor approach was adopted for these projects, this paper concentrates on the environmental applications of airborne gamma-ray data.

Nutrient elimination in pre-dams: results of long term studies

The results of inflow–outflow investigations carried out at the pre-dams of Saidenbach Reservoir (southeast Germany) show that the nutrient elimination in pre-dams is largely controlled by biological processes, mainly by the phytoplankton growth, and strongly depends on the retention time. Average SRP-elimination rates of up to 80% in summer and 60% in the whole year were observed in a pre-dam of `optimum size', which confirms the theory well. However, the mean total P reduction was much lower and did not even exceed 25% in the largest pre-dam in summer, since settling of particulate P (fine disperse suspended matter, phytoplankton) was restricted by the short retention time. The highest average summer nitrate elimination rate of 16% was found in a very shallow pre-dam and was mainly the result of extremely high denitrification at the sediment. Dissolved Si removal was low as well and reached average summer rates of up to 15%. In was correlated to the SRP-elimination in two basins. Fast siltation reduced the retention time and nutrient elimination capacity of the pre-dams. Thus, sediments have to be removed regularly from pre-dams.

Sediment Conditioning with Organic and/or Inorganic Carbon Sources as a First Step in Alkalinity Generation of Acid Mine Pit Lake Water (pH 2−3)

Laboratory scale microcosm studies were conducted to determine the efficacy of controlled in situ saprobization of lake sediments as one opportunity for deacidification of artificial shallow lakes resulting from open cast lignite mining located in southeast Germany. Under lasting anoxic conditions iron and sulfate were removed from the lake water as a result of microbial iron- and sulfate reduction together with a subsequent precipitation of insoluble sulfide minerals to the lake sediment. The 2 L closed system microcosms were made up of a model of the sediment/water interface. They were filled with lake water and sediment and treated subsequently with different organic and/or inorganic carbon sources in combination with wheat straw. Just the water was characterized initially and finally 8 weeks later. The rise of pH together with acidity consumption was observed. In the microcosms treated with wheat straw and pyruvate, ethanol, Carbokalk, or Pfezi-granula the pH rose to 5.5 and 7.0, respectively, and iron- and sulfate reduction were observed. With wheat straw and ethanol or Pfezi-granula sulfate concentrations decreased from initial concentrations of 11.5−13.5 mmol L-1 to final concentrations of < 3 mmol L-1. However, the iron concentration decreased significantly to a value of 0.01 mmol L-1 exclusively with Pfezi-granula and wheat straw. For the most reactive microcosms geochemical equilibrium calculations suggest precipitation of different sulfide minerals. The critical revision of the results obtained from this study indicate that ethanol or Carbokalk together with wheat straw are suitable for further upscaling in larger-scale microcosms.