A farewell to Dr Thomas Knacker (* 29.04.1951 – ？ 30.10.2011): scientific contributions and personal memories

Thomas Knacker was born in Wüstensachsen, a small village in East Hesse in what was then the Federal Republic of Germany, close to the border to the former East Germany (Figure 1). Despite living most of his life in Frankfurt and travelling all over the world, he always kept very close connections to his home region. As a young man, he served as a German Federal Border Guard (1969–1971), a period he later called the most boring time of his life. While he was never a typical member of the 1968 student movement, he kept, often with fine humour, his distance from authorities and he had a strong sense of social justice. Between 1972 and 1977, he studied biology, in particular plant physiology, biochemistry and microbiology at the Johann Wolfgang Goethe-University in Frankfurt am Main, serving several years as an elected student representative in the university council. Afterwards, while being supported by the “German National Merit Foundation”, he completed his Ph.D. thesis entitled “Measurements of the lipid content and the CO2-gas cycle and determinations of growth characteristics of Amaranthus paniculatus being grown under different oxygen concentrations” (1981) [1-3]. After a short stay at a governmental agency, he continued his studies on plant physiology at the Department of Biochemistry at the University College in Cardiff (Wales, UK). The time spent in Cardiff instilled in him a deep interest in and fondness for the English language and culture and rewarded him with long-lasting friendships.After his return to Germany, Thomas Knacker changed his scientific orientation considerably by joining the Battelle Institute in Frankfurt (1983). This private American contract research institute (in fact at that time the biggest world-wide) was focused on applied research. He was hired to set up a working group in ecotoxicology; a field of science barely established back then. Starting with three colleagues and using his broad and profound biological knowledge, Thomas Knack