Migration rhythm of the benthic diatom pinnularia virjdis on pond silt (Note)

Abstract

The vertical migration of the motile benthic diatom Pinnularia viridis(Nitzsch) Ehrenberg to and from the surface of silt was observed microscopically in a shallow pond in the Marlborough Sounds district, South Island, New Zealand. These diatoms moved up to the surface during the first 2 h after dawn and left after midday. This behaviour has previously been observed only in the laboratory. © 1976 Taylor & Francis Group, LLC.