ABSTRACT
Any organism living in flowing water—a rheophile—has mechanisms adapted to resist the current. The term living drift refers to the carrying and transport of organisms by the current. The aquatic drift affects all the organisms exposed to the current, but in different ways according to the species and their developmental stage. There is a constant drift of bacteria, algae, and benthic invertebrates, fortuitous for each individual, but regular along the length of a water course. One consequence of the drift, on a water course, is a constant tendency to homogenization of benthos and recolonization of the environment. The effect of homogenization is particularly perceptible during high water. Small species or those at juvenile stages, which can embed themselves in the alluvia, drift very little, as do species with heavy shells and those that adhere to the substrate. Resistance to the current obviously depends on the mode of fixation or attachment to the substrate.
