What is cyclomorphosis?

1. The history of the term cyclomorphosis and of research investigating the phenomenon it describes are reviewed briefly.
2. Several distinct definitions of this term appear in the limnological literature. Some of these definitions are consistent with earlier studies; others are not and are very restrictive and reliant upon extensive laboratory analysis.
3. We argue for the adoption of a broad definition of cyclomorphosis that is consistent with the majority of previous studies and practical to apply to the field populations it attempts to describe.
4. We also urge all researchers investigating this phenomenon to provide their working definition of this term in their reports in order to avoid terminological confusion.