Silicon limitation induces colony formation in the benthic diatom Nitzschia cf. pusilla (Bacillariales, Bacillariophyceae)

Abstract

While investigating the effects of silicon limitation on the diatom Nitzschia cf. pusilla, we observed, along with expected lower maximum cell density, colony formation. Cells attached in stacks that increased in number, reaching an average of 30 ± 1.8 (mean ± SE) cells per stack. Cells grown under silicon-replete conditions formed short stacks (three to four cells) in the stationary phase. When silicon-depleted cultures were split and silicate was added to half of the split cultures, cell stacks decreased in the cultures to which silicate was added. These results suggest that N. pusilla may possess an adaptive strategy to survive and maintain growth under silicon limitation.

Keywords:

• frustule
• meroplanktonic
• microphytobenthos
• nutrient limitation

Acknowledgements

We thank Jennifer L. Alix, Kimberly Dickinson, Kathy Shuo Zhai, and Scott M. Hawley for their assistance during the experiment. We also thank Dr. Marie Cantino and Steve Daniels in the UConn EM lab for their support and Dr. Eduardo Morales for his helpful suggestions. This project was supported by the NOAA National Aquaculture Program, through a National Research Council Post-Doctoral Fellowship to M.S.F., and by the Northeast Fisheries Science Center of the National Marine Fisheries Service.