A Simple System of Replicated Recirculating Experimental Streams

ABSTRACT

A system of recirculating artificial streams is described that has low initial cost and operating expense and operates efficiently over long periods of time. Although individual stream units are large enough to accommodate minnows and crayfish, they are sufficiently compact that replication with up to 12 streams is possible in a relatively small laboratory. The system is simple in design, with no moving parts (except pumps) and no costly flow meters or regulating devices. Replication of stream units is facilitated by depending on inlet ports of fixed size, full-capacity operation of pumps, and uniform diameters of distribution systems. A basic stream tank unit is described in detail, with techniques for combining up to 12 units for water-exchange and inflow-outflow of water in different experimental applications. We have operated the system for almost a year with very little cost or repair. Substrates incubated in the laboratory streams readily grow an algal flora similar to that of nearby natural streams, and fish, crayfish and snails exhibit normal activities in the streams. Total cost for construction of a 12-stream system was less than $3,500 U.S.