Abstract
The marine benthic diatoms in a soft-bottom substrate have been studied for about one year at six stations. Diatoms from the uppermost 5 mm of the sediment have been counted. Statistical analyses confirm that there are differences in the number of diatoms from station to station, and also differences in time within stations. The results indicate that most localities have a more or less prominent spring peak and for some stations also a late autumn maximum. Number of diatoms per mm3 varied from about 200 individuals (Stn 5) to about 2000 (Stn 6). Living diatoms were found down to about 16 cm in the sediment, even when there was some hydrogen sulphide at this depth at some of the stations. Arguments are presented for the importance of grazing as a controlling factor of diatom standing crop.
