First of all I would like to thank my supervisor Tom Headley at UFZ for all his help, support and encouragement both during the planning, the practical work and the writing stages of my thesis. Many thanks also to my other colleagues at UFZ, with whom it was a pleasure to work: Jaime Nivala and Kinfe Kassa for their great contributions to the field work and lab analyses, as well as for valuable help with other practical issues, Cristina Avila Martin for her contributions to the field work during the first weeks and for many valuable tips on all sorts of things, Katy Bernhard for the many drives to Langenreichenbach and all her help with field work and technical issues, and Grit Weichert for all her valuable help and cheerfulness in the lab (and for making me speak German). Herzlichen Dank to all ('Team LRB') for the great collaborations we had and for inspiring me in so many ways.

In addition, I want to thank Lars Westerberg at Linköping University for his great help with the statistical analysis, which I could not have done without his thorough explanations. Last but definitely not least I want to thank Karin Tonderski at Linköping University for always taking the time to give valuable comments on my draft, as well as for giving me the opportunity to do my thesis at the UFZ in Leipzig. My thesis in its present form would not have been possible without her help.