Synergistic effects of nutrients and lead on the quantitative ultrastructure of Cyclotella (Bacillariophyceae)

Abstract

A four-way completely crossed factorial enrichment experiment (2T×2Si×2Pb×2P) was used to analyze the short (2 hr) and long (48 hr) term effects of nutrients and lead on the quantitative ultrastructure of Cyclotella , a diatom. Some of the cytological modifications that have been reported to occur in other algae as a result of heavy metal exposure occurred in Cyclotella , but were mediated in some cases by the addition of low levels of nutrients. While it is extremely difficult to simulate the natural environment where a variety of parameters may be changing simultaneously, it is suggested that factorial design experiments approximate it more closely. Furthermore, environmental factors that may change the availability of metals may also change the physiological state of the cells, which may also either amplify or mitigate the metal effects.