The essential role of exopolymers (EPS) in aquatic systems

Abstract

Exopolymers (EPS) are exuded by single-celled and multicellular organisms. They consist mainly of carbohydrates that hydrate on contact with water and EPS are absorbent and often thixotropic. These properties result in a large number of uses: for attachments, as an aid to flotation, in locomotion, in feeding, for building structures, as the basis of biofilms, for protection against a number of harsh environmental conditions, as a barrier against attack by pathogens, parasitic organisms and predators, and in communication. In addition, EPS are found free in the water column where they form readily into gels and then into larger aggregates that are foci for biological activity and the breakdown of organic matter to provide nutrients. EPS are truly ubiquitous and are essential to the functioning of all aquatic ecosystems.