Algae

Abstract

Algae are susceptible to irreversible removal and downstream transport, and variability in the flow may lead to movement or suspension of substratum material, with a concomitant increase in turbidity and deprivation of light, to siltation and burial by disentrained sediment and, perhaps, to desiccation. Even when the physical environment is less exacting, such biotic factors as comparative rates of arrival, growth or selective removal (as food) by animals have profound effects upon the composition, abundance and temporal change in the algal assemblages present and, potentially, to the functional organization of the fluvial ecosystem. This chapter explores these selective mechanisms and makes some general deductions about their impact upon the structure and maintenance of the algal assemblages of flowing waters. The approach is to identify the interactions and limitations governing algal production in the principal habitats of the river, and then to emphasize those features impinging upon the contribution of algae to fluvial ecosystems. -from Author