Time filter

Source Type

Braunschweig, Germany

Giesemann A.,Johann Heinrich Von Thunen Institute
Analytical and Bioanalytical Chemistry | Year: 2010

Analysis of the stable isotope ratio of carbon (δ 13C) and α-linolenic acid (C18:3ω3) content in milk fat is a useful indicator of organic milk production. Referring to corresponding measurements, further analyses of stable isotope ratios were performed in 120 samples of conventionally and organically produced whole milk collected from German retailers during a period of 18 months. Conventional milk predominantly exhibited higher δ 15N values than organic milk, the latter of which never exceeded a maximum δ 15N threshold value of 5.50‰. Measurements of δ 34S did not differ significantly between organic and conventional milk. Because δ 13C, in general, is related to maize consumption, δ 13C in milk protein and δ 13C in milk fat were equally suited for authentication of organic milk. Thus, a high correlation (r = 0.99) was established between δ 13C in milk protein and lipids. Although occurring on different levels in organic and conventional milk, the relatively constant fractionation of carbon isotopes between protein and fat will allow for the advanced detection of adulteration in processed milk products, such as fraudulent combinations of organic milk fat and conventional skim milk. In addition to the strong correlation between C18:3ω3 and δ 13Cprotein (r = -0.91), a mutual dependence was identified between both δ 13Cprotein and δ 15N (r = 0.66) and C18:3ω3 and δ 15N (r = -0.61). Thus, multi-variable analyses are useful to increase robustness and reduce the number of exceptions in organic milk authentication. Future work involving multivariate statistical analysis can possibly further improve milk authentication in various respects including differentiating between brands of retail milk. © 2010 Springer-Verlag. Source

Roedl A.,Johann Heinrich Von Thunen Institute
International Journal of Life Cycle Assessment | Year: 2010

Purpose Ambitious targets for the use of renewable energy have recently been set in the European Union. To reach these targets, a large share of future energy generation will be based on the use of woody biomass. Therefore, there is an increasing interest in the cultivation of fast-growing tree species on agricultural land outside forests. Intensive crop production is always considered to harm the environment. The study explores the environmental burdens of the cultivation of fast-growing tree species on agricultural land and their subsequent energetic conversion in comparison to the fossil reference energy system. Methods Life cycle assessment (LCA) methodology according to the ISO 14040 and 14044 is used. Input data were partly collected within the German joint research project AGROWOOD. Two utilization paths of short rotation poplar chips are analyzed: heat and power generation in a cogeneration plant and the production of Fischer-Tropsch (FT) diesel. Subsequently, the bioenergy systems are compared with their fossil references. Results and discussion The production and distribution of 1 oven dry tonne (odt) of short-rotation poplar chips require 432 MJ non-renewable energy. This equals an output-input ratio of 43:1, which includes all process steps from field preparation to road transport. Emissions of this energy use amount to a global warming potential of 38.4 kg CO2 eq odt-1, an acidification potential of 0.24 kg SO2 eq odt-1, and a eutrophication potential of 0.04 kg PO 4 eq odt-1. The greatest reductions of environmental impacts can be achieved by substituting power from lignite with cogenerated power from short-rotation coppice (SRC). Compared with the average German power generation mix GWP and AP of power generation from short rotation poplar chips are lower by 97% and 44%, respectively, while eutrophication potential is about 26% higher. FT diesel made from shortrotation poplar chips has an 88% lower global warming potential and a 93% lower acidification potential than fossil diesel. But, the eutrophication potential of FT diesel is twice as high as of fossil diesel. Conclusions It was found that even intensively produced wood from SRC can reduce environmental burdens if it is used for biofuel instead of fossil fuel. The utilization of the same amount of short-rotation poplar chips for heat and power production causes fewer environmental impacts than its use for FT diesel. © 2010 Springer-Verlag. Source

Fock H.O.,Johann Heinrich Von Thunen Institute
Marine Policy | Year: 2011

The implementation of the Natura 2000 network of marine protected areas under the European Habitats Directive (92/43/EEC) has far-reaching implications for fisheries. To date, no consistent approaches have been established to develop fisheries management measures in Natura 2000 areas, and no European member state has proposed any fisheries measures to the European Commission for consideration under the Common Fisheries Policy. Four key issues are identified in the relationship between fisheries and Natura 2000, and the possible role that the future Common Fisheries Policy could have in this context is discussed. There is a need (1) for a consistent framework to integrate scientific advice, stakeholder participation and management in the management process; (2) for a common methodology to prioritize conservation objectives, in particular for transboundary protected areas; (3) for a consistent framework to assess and evaluate fisheries impacts to define management measures; and (4) to define spatial properties for fisheries. The results from the projects EMPAS (Germany), FIMPAS (the Netherlands), and INDEMARES (Spain) and the Dogger Bank case are discussed. © 2010 Elsevier Ltd. Source

A Relative Ecological Risk Assessment model is presented with an emphasis on risk calculation and risk characterization. Several types of impacts are incorporated including mortality, competition, and disturbance effects at different spatial scales exemplifying fisheries effects on benthic communities, marine mammals, and birds. Fisheries sectors analyzed are beam trawlers, demersal otter trawlers, gillnet, and sandeel fisheries in the German Exclusive Economic Zone of the North Sea. The basic ecological unit to which the risk score applies is the population/stock level or the distribution range of a community. The risk function comprises an exposure term and the loss function. The loss function is driven by a relative term, that is, the ratio between negative potential, that is, decline or mortality, and positive potential, that is, recovery. Sensitivity analysis is carried out to indicate model precision and its capabilities to distinguish between high and low risk areas and impacts. Limit reference values important for characterization of relative ecological risk are analytically defined. Model parameterization is based on literature review, and calculated examples show that beam trawling appears as a strong risk component to benthic communities, likely to exceed the limit reference value. For marine mammals (i.e., Harbour porpoise) in the German EEZ, by-catch in gillnet fisheries is a relatively strong risk. © Taylor & Francis Group, LLC. Source

Samples of 50 to 55 beech individuals (Fagus syh/atica L) from each of six selected progenies from a provenance trial (two from Germany, one from Austria, Czech Republic, Romania and Spain each) were genotyped with eight nuclear microsatellite markers to complete comprehensive phenotypical data collections. The detected partially strong deviations from the Hardy-Weinberg equilibrium within each population could be attributed to two essential sources: 1. A subpopulation structure consisting of two or three subpopulations in Hardy-Wein-berg equilibrium per provenance and 2.The existence of null alleles with remarkable frequencies at several marker loci. Furthermore, the representativeness of the seed harvest is indicated for five out of six population samples. In contrast to these, the provenance from Spain was harvested from obviously unbalanced portions or less than ten trees. This was concluded from the close relationship between twelve individuals out of 50, which seem to be a half-sib family. The comparison of genetic structures among populations demonstrates the clear separation of the Spanish provenance originating from the Iberian glacial refugium at the one side from the remaining five provenances originating from the south-eastern European refugium at the other side. A cluster analysis classified three provenances from more cold sites (Germany, Austria, Czech Republic) together into one group and two provenances from more warm sites (Germany, Romania) into another group. Source

Discover hidden collaborations