Use and misuse in the application of the phytoplankton functional classification: a critical review with updates

Since its publication, the article 'Towards a functional classification of the freshwater phytoplankton' (Reynolds et al., J Plankton Res 24: 417-428, 2002), has attracted the attention of dozens of phytoplankton ecologists worldwide. These numerous applications of the functional classification to describe phytoplankton patterns in various aquatic ecosystems allowed the recognition of some uncertain features of this concept originating from various reasons. In this article, we attempt to facilitate the application of the functional classification, by providing a detailed description of the typical misplacements and by modifying some of the original habitat templates and species allocations. Furthermore, we discuss in this review those coda that were additionally described after the publication of the original article, and attempt giving an overview, as complete as possible, of the state of art.