Trace metal dynamics in floodplain soils : a case study with the river Elbe in Germany
Since river-floodplain ecosystems are threatened by multiple stressors, the loss of these ecosystems still continues as does the loss of a multitude of ecosystem functions and services that are of great economic value to society (Oppermann et al. 2010). Some major threats to riparian ecosystems around the world include altered hydrological regimes due to river regulation and water extraction, the clearance of vegetation for agriculture and other developments, livestock grazing, the development of human settlements and infrastructure, pollution and mining (Tockner and Stanford 2002, Naiman et al. 2005). Global climate change is another threat that could impact river-floodplain ecosystems that are very vulnerable in this respect (Erwin 2009, Capon et al. 2013). To preserve river-floodplain ecosystems and their ecosystem functions and services, not only re-vitalisation measures but also sustainable management strategies as well as approaches for climate change adaptation and mitigation are absolutely imperative. This thesis aims to extend the existing knowledge on how river-floodplain ecosystems may be impacted by trace metal pollution and also covers aspects of climate change scenarios in floodplains, especially about the possibility that floodplain soils may shift from sinks to sources of potentially harmful solutes. For this, a floodplain segment along the lower Middle Elbe River was used as a model region. With a literature review on trace metal dynamics in floodplain soils, field measurements conducted over a three-year period to cope with seasonal changes in trace metal dynamics and a laboratory analysis to simulate a climate change scenario referring to stronger fluctuation between anaerobic and aerobic conditions in soils and related trace metal dynamics, the thesis covers several aspects of the recent discussion on this topic.