Morphological changes inSkeletonema costatum(Bacillariophyceae) during a spring bloom in a marine ecosystem enclosure

Abstract
During a spring diatom bloom in a large marine experimental enclosure, there was a significant increase in cell dimensions of Skeletonema costatum. Over a period of 2 days, the mean value of the pervalvar axis increased from 6·7 to 12·3 μm. This change in size occurred during a period of rapid population growth. Cell diameter did not show the same dramatic increase, although there was a significant increase in cell diameter over the 18-day period of the experiment. Nutrient concentrations were high and nutrient limitation is unlikely to have been the reason for the change in cell length.