Aufnahme von Cyanid in Pflanzen

Zusammenfassung  Cyanide entstehen bei der Pyrolyse von Kohle, und bei der Gasreinigung wird Blaus?ure als Berliner Blau gef?llt. Diese Abf?lle sind heute h?ufig Bestandteil von innerst?dtischen Altlasten. Cyanwasserstoff HCN (Blaus?ure) ist ein schnell wirksames und starkes Gift; eisenkomplexierte Cyanide im Boden sind jedoch weit weniger giftig. Die Phytotoxizit?t von freiem Cyanid wurde für Korbweiden (Sálix viminális) mit dem Baum-Transpirationstest bestimmt. Der EC₁₀ liegt für t=72 h bei 0,76 mg KCN (0,3 mg CN) je Liter, der EC₅₀ bei 4,47 mg/l KCN. Langfristig sind 5 mg/l KCN t?dlich. Balsampappeln (Pópulus trichocárpa) k?nnen in bis zu 2500 mg/l Ferroferricyanid (Berliner Blau) überleben, wenn auch mit Wachstumsst?rungen. Weiden überlebten in einem Gaswerksboden mit bis zu 452 mg/kg Gesamt-CN. Aus der N?hrl?sung wurde mehr freies CN aufgenommen als aus dem Boden. M?glicherweise wird auch komplexiertes Cyanid in die Bl?tter verlagert. In Erlenmeyern mit Pflanzen wurde freies Cyanid bei sublethaler Dosis rasch aus der N?hrl?sung eliminiert. Die Bepflanzung mit geeigneter Vegetation k?nnte eine L?sung für viele cyanid-kontaminierte Gaswerks- und Minengel?nde sein. OnlineFirst: 09. 01. 2001     

Effects of the juvenile hormone mimic ZR-512 (Altozar®) on larval development of the mud-crab Rhithropanopeus harrisii at various cyclic temperatures

Effects of the juvenile hormone (JH) mimic hydroprene (Altozar^®: ZR-512), which exhibits high activity against Lepidoptera, were studied on the larval development of the mud-crab Rhithropanopeus harrisii (Gould) (Brachyura: Xanthidae). Larvae reared in 20 S at 3 cycles of temperature of 20° to 25°C, 25° to 30°C and 30° to 35°C, were exposed to 0.01, 0.1 and 0.5 ppm hydroprene from hatching to the first crab stage. Larvae were also exposed to 0.1 and 0.5 ppm hydroprene only from the megalopa stage to the first crab stage. When larvae were treated with hydroprene throughout larval life, survival was significantly reduced with increasing concentrations of the compound at all temperature cycles. Synergistic effect between hydroprene and temperature on survival of zoeal larvae was not observed. On the average there was 11% less survival in the zoeal stages at the 0.01 ppm concentration. of hydroprene than in the control, an additional reduction of 13% occurred at 0.1 ppm, and finally there was a further decrease of 46% at 0.5 ppm hydroprene. Significant decrease in survival in the megalopa stage occurred only in the 0.5 ppm concentration of hydroprene at the lowest temperature cycle when larvae were exposed to the compound from hatching. When larvae were treated with hydroprene only within the megalopa stage, a significant reduction in survival was not observed. First-stage zoeae were the most sensitive of the larval stages to hydroprene. Duration of zoeal development was significantly delayed at 0.5 ppm hydroprene at the two lower temperature cycles, whereas in the megalopa stage the delay began at the 0.1 ppm level at all 3 temperature cycles when larvae were exposed to hydroprene from hatching. A significant delay was also observed at 0.1 ppm hydroprene at the two lower cycles when larvae were exposed to hydroprene only in the megalopa stage; at 30° to 35°C a significant delay was observed only at the 0.5 ppm level. The results show that metamorphosis to the first crab stage was not inhibited at the 0.5 ppm level of hydroprene or lower. Reduction in survival and increase in duration of larval development were presumably related to stress conditions caused by hydroprene. The results also suggest an interaction between temperature and hydroprene on survival of megalopa larvae and duration of larval development.     

Use of decision analysis interviews to support the sustainable use of the forests in Finnish Upper Lapland

Controversy between alternative uses of forests in Finnish Upper Lapland has been going on for decades, and in recent years it has been escalated to a serious conflict. The core of the conflict is the adverse impacts of forestry on old forests which are important grazing areas for reindeer and which are regarded as intact nature and wilderness areas. This paper describes the experiences of applying multi-criteria decision analysis interview approach on this conflict. The approach provides tools for structuring the problem and preferences of the stakeholders as well as for analyzing the effects of different alternatives in a common framework. We focus on the practical experiences gained from the application of this approach in this context. Multi-criteria decision analysis was found to be a useful approach to evaluate the economic, ecological and cultural aspects of this intense conflict. The obtained experiences also support the view that the approach works best when tightly integrated into the planning process.     

Climate adaptation of biodiversity conservation in managed forest landscapes

Conservation of biodiversity in managed forest landscapes needs to be complemented with new approaches given the threat from rapid climate change. Most frameworks for adaptation of biodiversity conservation to climate change include two major strategies. The first is the resistance strategy, which focuses on actions to increase the capacity of species and communities to resist change. The second is the transformation strategy and includes actions that ease the transformation of communities to a set of species that are well adapted to the novel environmental conditions. We suggest a number of concrete actions policy makers and managers can take. Under the resistance strategy, five tools are introduced, including: identifying and protecting forest climate refugia with cold-favored species; reducing the effects of drought by protecting the hydrological network; and actively removing competitors when they threaten cold-favored species. Under the transformation strategy, we suggest three tools, including: enhancing conditions for forest species favored by the new climate, but currently disfavored by forest management, by planting them at suitable sites outside their main range; and increasing connectivity across the landscape to enhance the expansion of warm-favored species to sites that have become suitable. Finally, we suggest applying a landscape perspective and simultaneously managing for both retreating and expanding species. The two different strategies (resistance and transformation) should be seen as complementary ways to maintain a rich biodiversity in future forest ecosystems.     

Development of a combined isotopic and mass-balance approach to determine dissolved organic carbon sources in eutrophic reservoirs

A combined mass-balance and stable isotope approach was set up to identify and quantify dissolved organic carbon (DOC) sources in a DOC-rich (9 mg L⁻¹) eutrophic reservoir located in Western France and used for drinking water supply (so-called Rophemel reservoir). The mass-balance approach consisted in measuring the flux of allochthonous DOC on a daily basis, and in comparing it with the effective (measured) DOC concentration of the reservoir. The isotopic approach consisted, for its part, in measuring the carbon isotope ratios (δ¹³C values) of both allochthonous and autochthonous DOC sources, and comparing these values with the δ¹³C values of the reservoir DOC. Results from both approaches were consistent pointing out for a DOC of 100% allochthonous origin. In particular, the δ¹³C values of the DOC recovered in the reservoir (−28.5 ± 0.2‰; n = 22) during the algal bloom season (May-September) showed no trace of an autochthonous contribution (δ¹³C in algae = −30.1 ± 0.3‰; n = 2) being indistinguishable from the δ¹³C values of allochthonous DOC from inflowing rivers (−28.6 ± 0.1‰; n = 8). These results demonstrate that eutrophication is not responsible for the high DOC concentrations observed in the Rophemel reservoir and that limiting eutrophication of this reservoir will not reduce the potential formation of disinfection by-products during water treatment. The methodology developed in this study based on a complementary isotopic and mass-balance approach provides a powerful tool, suitable to identify and quantify DOC sources in eutrophic, DOC-contaminated reservoirs.     

Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs

Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N₂ allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.     

Reflections on the use of Bayesian belief networks for adaptive management

A broad range of tools are available for integrated water resource management (IWRM). In the EU research project NeWater, a hypothesis exists that IWRM cannot be realised unless current management regimes undergo a transition toward adaptive management (AM). This includes a structured process of learning, dealing with complexity, uncertainty etc. We assume that it is no longer enough for managers and tool researchers to understand the complexity and uncertainty of the outer natural system-the environment. It is just as important, to understand what goes on in the complex and uncertain participatory processes between the water managers, different stakeholders, authorities and researchers when a specific tool and process is used for environmental management. The paper revisits a case study carried out 2001-2004 where the tool Bayesian networks (BNs) was tested for groundwater management with full stakeholder involvement. With the participation of two researchers (the authors) and two water managers previously involved in the case study, a qualitative interview was prepared and carried out in June 2006. The aim of this ex-post evaluation was to capture and explore the water managers' experience with Bayesian belief networks when used for integrated and adaptive water management and provide a narrative approach for tool enhancement.     

Pollution and potential mobility of Cd, Ni and Pb in the sediments of a wastewater-receiving river in Hanoi, Vietnam

Large quantities of untreated industrial and domestic wastewater are discharged from the city of Hanoi into urban rivers. Sediment samples from three sites in the To Lich River in Hanoi were assessed with respect to the concentrations and potential mobility of cadmium (Cd), nickel (Ni) and lead (Pb). Due to very high Cd concentrations up to 700 mg kg^?1 at one site, the sediment was considered highly unsuitable for any types of land use if dredged and disposed of on land. Chemical sequential extractions of wet and anoxic sediment samples showed that Cd and Pb were largely associated with the redox-sensitive fractions and could thus be mobilised following measures such as resuspension or dredging. To assess the potential mobilisation of heavy metals from the anoxic sediment due to oxidation, the samples were exposed to different oxidants (i.e. atmospheric air and hydrogen peroxide) and afterwards submitted to a leaching test. These experiments showed that although oxidation may increase the equilibrium pore water concentrations of heavy metals in the sediments, other sediment mineral fractions seem to effectively immobilise heavy metals potentially released from the oxidisable fraction.     

MEAD: an interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat

This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.