A farewell to Dr Thomas Knacker (* 29.04.1951 - DR 30.10.2011)

On October 30, 2011 we lost Dr. Thomas Knacker, a much valued and loved colleague, research partner and friend. We deeply regret the loss of an internationally honoured ecotoxicologist. The colleagues and friends that wish to express their sorrow in this contribution include individuals from a variety of organisations and academic institutions in Europe and abroad.