Substrate choice and settlement preferences of planula larvae of five Scyphozoa (Cnidaria) from German Bight,North Sea

The settlement behaviour of planula larvae and their development to young polyps was investigated in laboratory experiments in five scyphozoan species [Aurelia aurita (L.), Cyanea capillata (L.), Cyanea lamarckii Péron and Leseur, Chrysaora hysoscella (L.), and Rhizostoma octopus (L.)]. The undersides of settling plates were strongly preferred for settlement. Shells, the only natural substrate type offered, were less attractive than artificial substrates (concrete, machined wood, polyethylene, and glass). The advantages of colonization of substrate undersides for survival and reproduction of polyps are discussed. It is supposed that the increase of artificial substrates in our seas, due to marine litter pollution and submarine building activities, enlarge the areas of distribution of scyphozoan polyps, in coastal as well as in off-shore regions. Subsequent increases in ephyra production by polyps are probably one reason for the increase in mass occurrences of jellyfish recognized worldwide during the last few decades. It is suggested that the early developmental stages in the cnidarian life cycle, the planula larvae, and the polyps, play the key role in the development of jellyfish outbursts.     

Systematische Exploration stoffbezogener Umweltproblematiken

With the aim of providing results for precautionary environmental politics at an early point in time, a strategy is being sought to optimize the identification of research objects in substance-related environmental research. Both, proven as well as potential substance risks are considered as such. This approach is meant to support pro-active elements in environmental chemistry (as opposited to re-active elements associated with environmental damage). In the atmosphere, substance risks are created by perturbations of functions of the atmosphere and of other natural spheres, as far as atmospheric functions are part of the cause-effect relationships. A complete risk assessment includes exposure and effects analyses, a prerequisite for the latter is the identification of critical effect thresholds (in general: criticalities). However, the state of knowledge in many cases does not allow for a quantitative analysis of the cause-effect relationships. Exposure analysis can be significant for the identification of relevant research objects, because the quantification of the spatial and temporal extent of the potential damage constitutes an important risk category which can be addressed by exposure analysis. Examples for priority issues of substance-related environmental research are given based on combined exposure and effect analyses, as well as on exposure analyses alone. References for the knowledge production process in substance-related environmental science are provided in the field of risk assessment and using the syndrome concept.     

Influence of platinum, palladium and rhodium as compared with cadmium, nickel and chromium on cell viability and oxidative stress in human bronchial epithelial cells

The platinum group elements (PGE) Pt, Pd and Rh are increasingly emitted into the environment by automobile catalytic converters. Whereas the biological availability of PGE to plants and animals has been demonstrated, only few studies concentrate on the influence of PGE on a cellular level. The effects of Pt, Pd and Rh compared with Cd, Ni and Cr on cell viability and oxidative stress response using soluble metal salts were studied in the human bronchial epithelial cell line BEAS-2B. Whilst Rh(III) showed little influence, both Pt(II) and Pt(IV) as well as Pd(II) had significant effects on cell viability at levels comparable to Cd(II) and Cr(VI). Arranging metal species in order of increasing toxicity as determined by LC50 yields: Rh(III)=1.2 mmol/L相似文献