Analyse von polycyclischen aromatischen Kohlenwasserstoffen (PAK)

An interlaboratory test was organized by the Allgemeine Unfallversicherungsanstalt, Dept. HUB (Department for the Prevention of Occupational Accidents and Diseases) for the analysis of polycyclic aromatic hydrocarbons (PAH). The aim of the test was to compare analytical results of serveral laboratories performing PAH analysis as routine work. In a preliminary study four different PAH-containing solutions were analyzed by independent laboratories in Germany and Austria. The concentrations of 17 PAH (according to the relevant NIOSH-methods) were to be determined. The results reveal the problems involved in the analysis of PAH.     

The parthenogenetic Marmorkrebs (marbled crayfish) produces genetically uniform offspring

Genetically identical animals are very much in demand as laboratory objects because they allow conclusions about environmental and epigenetic effects on development, structures, and behavior. Furthermore, questions about the relative fitness of various genotypes can be addressed. However, genetically identical animals are relatively rare, in particular, organisms that combine a high reproduction rate and a complex organization. Based on its exclusively parthenogenetic reproduction mode, it has been suggested that the Marmorkrebs (Crustacea, Decapoda, Astacida), a recently discovered crayfish, is an excellent candidate for research addressing the aforementioned questions. However, until now, a study using molecular markers that clearly proves the genetic uniformity of the offspring has been lacking. Here, with this first molecular study, we show that this crayfish indeed produces genetically uniform clones. We tested this with 19 related individuals of various generations of a Marmorkrebs population by means of six different microsatellite markers. We found that all examined specimens were identical in their allelic composition. Furthermore, half of the analyzed loci were heterozygous. These results and the absence of meioses in previous histological studies of the ovaries lead us to conclude the Marmorkrebs propagates apomictically. Thus, a genetically uniform organism with complex morphology, development, and behavior is now available for various laboratory studies.     

Ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus Apiognomonia errabunda of adult European beech trees

In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’ to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2× ozone) and three control trees (ambient = 1× ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection.     

Proximate causes of deforestation in the Bolivian lowlands: an analysis of spatial dynamics

Forests in lowland Bolivia suffer from severe deforestation caused by different types of agents and land use activities. We identify three major proximate causes of deforestation. The largest share of deforestation is attributable to the expansion of mechanized agriculture, followed by cattle ranching and small-scale agriculture. We utilize a spatially explicit multinomial logit model to analyze the determinants of each of these proximate causes of deforestation between 1992 and 2004. We substantiate the quantitative insights with a qualitative analysis of historical processes that have shaped land use patterns in the Bolivian lowlands to date. Our results suggest that the expansion of mechanized agriculture occurs mainly in response to good access to export markets, fertile soil, and intermediate rainfall conditions. Increases in small-scale agriculture are mainly associated with a humid climate, fertile soil, and proximity to local markets. Forest conversion into pastures for cattle ranching occurs mostly irrespective of environmental determinants and can mainly be explained by access to local markets. Land use restrictions, such as protected areas, seem to prevent the expansion of mechanized agriculture but have little impact on the expansion of small-scale agriculture and cattle ranching. The analysis of future deforestation trends reveals possible hotspots of future expansion for each proximate cause and specifically highlights the possible opening of new frontiers for deforestation due to mechanized agriculture. Whereas the quantitative analysis effectively elucidates the spatial patterns of recent agricultural expansion, the interpretation of long-term historic drivers reveals that the timing and quantity of forest conversion are often triggered by political interventions and historical legacies.     

Carbon-optimised land management strategies for southern Amazonia

Regional Environmental Change -