Tom Fenchel is a Danish marine ecologist who has coalesced physical, mathematical and biological concepts to shape our understanding of ecological processes in the sea. He is distinguished for his work revealing the roles and population biology of microfauna in aquatic environments, for example the ‘microbial loop’ of carbon cycling.

Tom was instrumental in the discovery and description of the microbial loop — a trophic pathway in the marine microbial food web. The pathway highlights the role of marine bacteria in supplying a carbon source for higher microorganisms, and is one of many insights Tom has contributed on the important part played by microbes in the ocean environment.

Tom also developed ‘Fenchel’s law’, a mathematical tool used by population biologists to calculate the maximum reproductive rate of organisms, which decreases with body size. His work has been recognised by international awards, including the 2006 A. C. Redfield Lifetime Achievement Award, and he has written several textbooks.