The unidirectional flow of water in streams provides
benthic organisms with a continuous supply of
nutrients, in addition to oxygen, and removes metabolic
wastes. From a stoichiometric viewpoint, this
arrangement limits the ability of sessile, benthic
organisms to alter the chemical environment to which
they themselves are exposed, although downstream
communities could be affected. Recognising this
condition led to the concept of nutrient spiralling,
and the spiralling framework has organised our
thinking about stream biogeochemistry ever since