Phytoplankton designer - or how to predict compositional responses to trophic-state change

An exercise in which experienced phycologists were invited to nominate ('design') the phytoplankton of a lake, given a description of the physical and chemical conditions, is reported. Few intuitively reversed the process by which they might judge the source of a given unattributed sample on the basis of the algal assemblage. It is argued that the power of preferential selection of particular adaptations of phytoplankton can be invoked predictively through resort to Functional groups ('associations').