Schlieren Technique for Studying Water Flow in Marine Animals

Abstract

A Schlieren optical technique has been developed for studying the flow of water through certain mollusks and brachiopods in sea-water environments. Optical contrast is accomplished by changing either the temperature or salinity of the water. A temperature difference of 0.1° C or a change in salinity of 0.5 per thousand over a path 1 mm long is visible. The technique may be applied in situ in the ocean or through windows in aquaria.