The mesocosm dilemma: Need and trouble of synchronizing ecological processes in preperation of ecotoxicological studies

Abstract

For the risk assessment of chemicals, exposure-response studies are demanded preferably with multiple replications in order to increase the test power. However, the higher the ecological realism of such studies, the lesser replications are feasible due to increasing costs and workload. In full system mesocosm studies the dilemma of demanding both, realism and ecological synchronism between systems prior to dosing the test chemical, increases with system complexity. It is surprising though, that means to improve ecological synchronism have hardly been paid attention to so far even although variability in the data may be reduced considerably. Since 2001 the German Federal Environment Agency runs an artificial stream and pond mesocosm system (FSA) consisting of 8 indoor and 8 outdoor ponds and streams, respectively. Due to the FSAs limitations in replication, the synchronisation of ecological processes for exposure-response studies has always been a major research issue. With this contribution it is attended to spread the experience gained concerning effort and methods to achieve synchronism and to compare it with other research findings.Quelle: http://www.sgmeet.com