An Artificial Stream Apparatus for the Study of Lotic Organisms

It has been shown that a current of water is required by certain species of plants and animals. Apparatus to produce a current have been devised for the study of such organisms by several investigators. As early as 1956, one of us used an artificial stream set up in a constant temperature room to determine the effect of a current on the growth of freshwater algae. With it, data were obtained on the effect of a current vs. still water on species having a low light requirement, but it was evident that it would be difficult to raise the intensity of artificial illumination to that of an outdoor environment in spring and summer so that species requiring high light intensities could be tested. Since outdoor light can be controlled by shading, the obvious solution is to place the apparatus in sunlight, but in sunlight some method of controlling water temperature is necessary. Such an artificial stream apparatus has been devised and set up in a greenhouse to eliminate interference by dust, flying insects, and storms.