Effect of salinity on uptake of 14C-2,2′4,5,5′-pentachlorobiphenyl by juvenile Atlantic salmon

Uptake of ¹⁴C-2,2′,4,5,5′-pentachlorobiphenyl by appropiately adapted juvenile Atlantic salmon (Salmo salar) is more efficient from fresh water than from sea water. Concentrations of ¹⁴C-2,2′,4,5,5′-pentachlorobiphenyl in the whole body as well as in a number of organs and tissues were substantially higher in salmon exposed in fresh water.     

Growth and social behavior in a cichlid fish are affected by social rearing environment and kinship

Living in groups is a widespread phenomenon in many animal taxa. The reduction of predation risk is thought to be an important cause for the formation of groups. Consequently, grouping behavior is particularly pronounced during vulnerable life stages, i.e., as juveniles. However, group living does not only provide benefits but also imposes costs on group members, e.g., increased competition for food. Thus, benefits of grouping behavior might not be evident when predation risk is absent. The adaptive significance of living and also developing in a group independent from predation risk has received relatively little attention although this might have important implications on the evolution and maintenance of group living. The first aim of the present study was to examine whether the social environment affects juvenile performance in the cichlid fish Pelvicachromis taeniatus and, secondly, whether kinship affects social behavior. Kin selection theory predicts benefits from grouping with kin. Here, we demonstrate that juveniles reared in a group grow on average faster compared to juveniles reared in isolation under standardized laboratory conditions without predation risk. Furthermore, we found significant differences in social behavior between juveniles reared in a group and reared in isolation. Fish reared in isolation were significantly more aggressive and less willing to shoal than group-reared fish. As expected, genetic relatedness influenced social behavior in group-reared fish as well: dyads of juveniles consisting of kin showed increased group cohesiveness compared to non-kin dyads. We discuss the potential benefits of group living in general and living with kin in particular.     

Staubfilterung und immissionshistorische Aspekte am Beispiel fassadenbegrünenden Wilden Weines (Parthenocissus tricuspidata)

Goal and Scope

At the present, air borne particulate matter is in the focus of public and scientific interest. In this context, it makes sense to remember the buffer function of vegetation for particulate air pollutants, notwithstanding technical and traffic management measures. Since trees with large and dense crowns might be able to shade windows and minimise the turbulent dilution of pollutants, natural-scientific results and socio-scientific aspects will point to the potentials of vertical greening with creeping plants.

Methods

To differentiate the endogenous and exogenous element fractions, the pollution caused by dust that covers the façade climbing creepers leaves was removed by a polyvinyl-butyrale based stripping method. The cleaning success is proven by SEM-Scans. The results of cleaned and not cleaned leaf-samples from an inner-city vertical greening for the element concentrations of Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, Pt, Rh, Sb and Zn between 1991 and 1997 are shown by AAS- and ICP-MS analyses.

Results and Conclusion

The results show the increasing element concentrations during the course of the separate vegetation periods. Due to the long investigation period, it is possible to detect historical aspects concerning pollution, such as the end of the use of leaded fuel and the introduction of the catalytic converters. The comparison of dust deposition data from different cities shows the relevance of the pollution filtering by vertical greenings with Japanese Creeper. The comparison of investigation results of sycamore leaves refer to entirely different filtering characteristics of the leaf-surfaces.

Recommendation and Perspective

If appropriate planning and maintenance is assured, vertical greening can be a useful contribution for air pollution control and neighbourhood improvement. As selected results from a survey show, from the citizens point of view, the aesthetical and psychosocial aspects of well-being are of more relevant than ecological arguments. Therefore it seems to be wise to implement the combined fields of interest.