Longitudinal patterns and response lengths of algae in riverine ecosystems: a model analysis emphasising benthic-pelagic interactions.

•Effects of non-linear processes can be analysed by spatial equilibrium values.•In shallow rivers phytoplankton can exist only when it is subsidised by benthic algae.•In deep rivers benthic algae can exist only when they are subsidised by phytoplankton.•The distance needed to recover after spatial disturbances increases with depth.