Die Bedeutung der Zeit

Reflecting on time and its nature has a long tradition in such fields as philosophy, economy and the social sciences. In environmental sciences, however, time has not been taken into sufficient consideration to date, although many ecologists are indeed aware of its importance. Because of the importance of time for mankind, nature and the surrounding world, an outline incorporating time is possible and would lead to new insights in environmental sciences. Here, our idea of a balanced or “healthy” ecosystem, or the consequences of our actions such as depletion of the ozon layer, the greenhouse effect or floods are taken into consideration. A reflection on time its a basic requirement for our understanding of environmental science, its tools and our environmental and political actions. A consideration of time in environmental sciences means, among other things, to think of and to act in accordance with time scales and the rhythms of man and nature.     

Die Bedeutung des organischen Kohlenstoffs im Unterboden

The organic carbon distribution among holorganic, topsoil, and subsoil horizons was determined for a series of 103 forest soils. The results show that only 25% and 36% of total organic carbon are stored within holorganic layers and topsoil, respectively. Subsoil was found to be the most significant compartment representing 39% of the carbon pool. This kind of distribution emphasizes the great importance of future research on structure and stability of subsoil organic carbon.     

Die Umsetzung der FFH-Richtlinie in der Agrarlandschaft

The EU Habitats Directive (92/43/EEC) does include provisions for setting up the Natura 2000-network of protected areas based on listed species and habitats, and in addition specific regulations on species protection. Three Quarters of all designated sites (SCI’s) do not only include natural habitat types in a strict sense like forests or water-bodies, but also agricultural land. 18?% of the SCI’s even include between 25 and 50?% agricultural land and 24?% above 50?%. 48 species and three habitat types listed under the Habitats Directive have a clear focus in agriculture. Another eleven habitat types are dependant from a nature-friendly low intensity use or management. A large proportion of these habitats and species are actually in an unfavourable conservation status. The paper analyses the impact of EU nature conservation on agriculture based on the species and habitats falling under the Habitats Directive. On the other hand indirect negative influences of agriculture are discussed, that may have considerable impact on the future development of the conservation status of endangered habitats and species.     

Die Bedeutung von Lebensmitteln tierischer Herkunft für die Mykotoxinaufnahme beim Menschen

Mycotoxins are a heterogeneous group of secondary fungal metabolites. Their formation in food and feedstuffs is influenced by many factors, including humidity, temperature, pH, oxygen concentration, type of substrate or presence of competitive microflora. The Food and Agriculture Organisation of the United Nations estimated in 1985 that approximately 25% of the world’s grain supply is contaminated with mycotoxins. There are more than 300 known mycotoxins; however, due to their occurrence and concentrations in food, and their toxic potential, only few of these are relevant with regard to consumer protection. These include the aflatoxins, ochratoxins and trichothecenes like deoxynivalenol, zearalenone and fumonisins. In Germany, only aflatoxins in food and feedstuffs are subjected to legal regulations. Beside the negative effects of mycotoxins on health and performance of farm animals, it is of importance to consider to what extent mycotoxins might be carried over into edible tissues like meat, milk and eggs when fed to farm animals. The present review shows that the carry over of mycotoxins into edible tissues is relatively low and is dependent on the specific mycotoxin and animal species. For example, due to the microbial decomposition of mycotoxins in the rumen, the carry over of mycotoxins into edible tissues of ruminants is considerably lower compared to monogastric species (pigs, chickens). Furthermore, after a short withdrawal period of 4 to 14 days combined with the feeding of non-contaminated diets, most of the mycotoxins, aside from ochratoxin A, are no longer detectable in any edible tissue. Ochratoxin A has a high binding affinity to specific blood proteins and is reabsorbed in the kidney; these mechanisms delay its elimination and increase the withdrawal period to at least 4 weeks. However, aside from the concentration of these substances in food, the daily intake of contaminated food is important for the risk analysis of mycotoxins to humans. In a recent study, it has been shown that more than 50% of the daily intake of ochratoxin A is derived from cereals and cereal products, and 30% from red wine, coffee and beer. Mear products from pigs and chickens only account for 4% of the total intake, while products from ruminants are considered to be negligible. These results indicate that mycotoxin-contaminated edible tissue, as compared to plant products, only plays a minor role with respect to consumer protection.     

Bedeutung der Expositionswege auf Bioakkumulation und Wirkung in C. elegans

Different uptake routes of contaminants were analysed with focus on particle-bound pollutants. Bioavailability of cadmium was determined with quantitative mRNA-analysis using the expression of the “cadmium responsive gene” cdr- in Caenorhabditis elegans. Comparable experiments were performed with fluoranthene as organic pollutant. The exposure in medium was compared with and without bacteria as food particles. Both bioaccumulation and toxic effects were most influenced via the food exposure. Inorganic particles increased also the uptake of cadmium, but significantly less than food or mixtures of food and inorganic particles. The exposure of fluoranthene reduced the reproduction of the nematodes, if a gene expression threshold was exceeded. However, bioavailabilty of fluoranthene via food particles caused a faster response of the cyp-expression. Thus means, the internal availability is crucial influenced by the uptake route.     

Die Rolle von Kommunikation in der Umweltbewertung

Goal and Scope

Planning projects concerning the environment often provoke problems due to a lack of transparency of the applied scales and the appropriate evaluation methods. This paper therefore examines the general structure of all valuation processes before describing the character of the economic evaluation method in detail. From this point of view, requirements on planning processes are coming out which are to be achieved if their duty — the provision of public goods — is to be carried out efficiently.

Features

It will be shown that from an economist’s perspective a planning procedure acts as a surrogate of the market in coordinating individual’s preferences. The reasons for the inefficient level of the provision of environmental goods by private producers are their main characteristics: non-rivality and non-excludability; therefore public goods do not possess prices. Thus environmental goods have to be produced by cooperation and planning processes have to guarantee this. The main character of planning procedures is be seen in communication processes which is documented by a narrative study.

Results and Conclusions

Planning projects concerning the environment are strongly contingent on communication processes. Thus, they are also controllable by communication. The interdisciplinary research in communications shows that cooperative behaviour which is required for planning projects that should provide public goods can be benefited by applicative communication technologies. In this juncture (social) norms more and more emerge to act an important part in conveying cooperative behaviour. Especially so called ‘Sozialtechniken’ seem to be able to activate such norms.

Outlook

From the economist’s point of view planning projects concerning the environment mostly desiderate two things: Firstly, the procedures and methods which are applied to evaluate the regarding environmental goods in many cases suffer from transparency. Secondly, individual’s preferences predominant by the local population and accordingly by the directly involved parties are mostly not acquired adequately to achieve an efficient allocation of environmental goods. Applying more communication technologies to solve these two problems in the future both an increase of efficiency and an increase of the acceptability of such planning projects can be expected.     

Die wirkung der sauerstoffspannung auf die druckresistenz einiger mariner wirbelloser

Variations in oxygen tension exert a considerable influence on the resistance of invertebrates to high hydrostatic pressure. Pressure resistance of whole animals (Idotea baltica, Cyprina islandica) and of isolated tissues (gill tissues of Cyprina islandica and Mytilus edulis) is higher in a medium not fully air saturated; it decreases with increasing oxygen tension to about air saturation or higher. In some species, pressure resistance decreases when dissolved oxygen is almost absent. Oxygen tension influences pressure resistance not only during exposure to increased pressure; our experiments revealed that pressure resistance increases in isolated tissues kept under oxygen deficiency prior to the experiment. Lactic acid, a result of anaerobic glycolysis, increases cellular pressure resistance only if its presence is combined with decreased pH values. Metabolic inhibition with cyanide does not increase pressure resistance. It is suggested that the primary reasons for lowered pressure resistance at saturation or higher oxygen levels are oxydation and inhibition of sensitive SH-enzymes under pressure. Decrease of pressure resistance at extreme degrees of oxygen deficiency may be due to insufficient rates of ATP synthesis. According to Marsland (1957), ATP is required for maintenance of protoplasmic gel structures. Correlations between pressure resistance and oxygen tension are of special importance in deep-sea animals, which often have to face reduced oxygen contents in their ambient medium.