Title: Migration rhythm of the benthic diatom<i>Pinnularia virjdis</i>on pond silt (note)
Abstract: 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.