A lotic ecosystem is the ecosystem of a river, stream or spring. Included in the environment are the biotic interactions (amongst plants, animals and micro-organisms) as well as the abiotic interactions (physical and chemical).[1]
Lotic refers to flowing water, from the Latin lotus, past participle of lavere, to wash. Lotic ecosystems can be contrasted with lentic ecosystems, which involve relatively still terrestrial waters such as lakes and ponds. Together, these two fields form the more general study area of freshwater or aquatic ecology.
Lotic waters can be diverse in their form, ranging from a spring that is only a few centimeters wide to a major river that is kilometers in width.[2] Despite these differences, the following unifying characteristics make the ecology of running waters unique from that of other aquatic habitats.[3]