Effect of ageing on survival of benthic diatom propagules

A comparison of viable benthic diatom propagules based on the observations recorded immediately and after 5 years of ageing at 5 °C is presented. The number of viable benthic diatom propagules decreased with ageing. However, they exhibited an apparently longer lag phase. Although diatoms belonging to the genera Amphora, Navicula and Thalassiosira were dominant during immediate observation, only Amphora and Navicula survived the ageing process. The non-viability of Thalassiosira indicates that ageing for five years was beyond its critical period of survival. The other diatom genera that survived the ageing process were Odontella and Grammatophora.