Biomonitoring in two tributaries of Lake Constance. Life-history-traits, histopathology and stress protein analysis in gammarids.
|Room:||306, 2nd floor, Auf der Morgenstelle 5|
|send a mail||katharina.peschke [at] uni-tuebingen.de|
Aim of the study
In the context of “SchussenAktiv” the aim of my thesis is to evaluate the suitability of amphipods as indicators of micropollutant-related effects. Micropollutants, like pesticides, pharmaceuticals, industrial chemicals and complexing substances etc. are chemicals, which can be detected in the environment in very low concentrations. Even in these low concentrations, however, they can induce negative effects in exposed organisms. By a variety of ecotoxicological methods including biomarkers, these effects in organisms can be demonstrated. In conventional Sewage Treatment Plants (STPs), micropollutants are not or only partially eliminated and therefore remain in surface waters in relevant concentrations. Active carbon treatment is a possibility to extract micropollutants from the water cycle. The installation of an active carbon treatment stage at the sewage treatment plant Langwiese (AZV Mariatal) which is connected to the Schussen, a tributary of Lake Constance, started in autumn 2010.
An important aspect of my thesis is to investigate endocrine disruption potentials in the effluent of this STP. In the last decades, increasing attention has been paid to evaluate adverse effects of endocrine disrupting chemicals in aquatic environments. For several vertebrate species certain phenomena related to such effects, like sex conversion or disruption of mating behaviour have been described. In invertebrates, endocrine disrupting chemicals can also interfere with complex hormonal regulation in many ways; however, only few studies are related to endocrine disruption in invertebrates. Invertebrates are important members of aquatic biocoenosis. A decline of populations caused by endocrine disruption may have a strong impact on aquatic food webs. For my PhD thesis, two gammarid species are used as monitor organisms: Gammarus pulex (Linné 1835) and Gammarus roeseli (Gervais 1835). Gammarids are important members of aquatic food webs, particularly for fish. As monitor organisms, they are excellent, since they are widely distributed, occur in large numbers of individuals, have a relatively short generation time and high reproductive rates and are characterized with high sensitivity to pollutants. Sampling sites for gammarids are located at two tributaries of Lake Constance, Schussen and Argen. Sampling upstream and downstream the STP Langwiese allows investigating the influence of the effluent on the test organisms. Sampling prior and after the treatment plant expansion allows reflecting its positive effect on the health of gammarids.
Different methods are used to show effects in gammarids. The determination of the sex ratio and fecundity provides evidence of estrogen and estrogen-active substances. The incidence of parasitized individuals points to a possible weakening of the immune system, which also can be related to a polluted environment. By histopathological studies, the impact of the parasite on the tissue health of the host is documented. Analyses of oocyte maturation stages and the analyses of the Hsp90 levels also allow detecting endocrine effects. Analyses of the Hsp70 levels allow us to draw conclusions on the general state of stress of the test organism.