Abstract
Wadden Sea inhabiting diatoms often show a patchy distribution on sediment surfaces with areas of higher and lower cell densities. The factors causing patchiness have not been clearly worked out and are under debate. Even the mode of reaching the sediment surface is almost completely unknown.
The observations indicate that trails of individual diatoms might be used by others for upward directed migration and offer another plausible explanation for the existence of surfaces areas of higher and lower cell densities in general.