Theoretical understanding of morphological variations in diatoms

Phenomenon of morphological variations (MV) is well known in diatoms. But, comprehensive study on MV in diatoms are still lacking. So, in the present study, data available on online image database “Diatoms of North America” (DONA) has been taken to explore MV phenomenon in diatoms at morphological and ecological basis. Our study for the time reported that MV phenomenon is more frequent in larger and asymmetrical diatoms than smaller and symmetrical forms. Similarly, in different life-forms and guilds, MV phenomenon is more less frequent in benthic and motile forms, respectively. In cosmopolitan diatom genus, the extent of MV reaches >90%, except araphid and monoraphid genus. Thus, from the finding of present study we conclude that MV phenomenon in diatoms is remarkable, which may affect diatomaceous research output expressed as taxonomical (deformities, biodiversity indices etc.) and non-taxonomical (lipid bodies, protoplasmic content etc.) metrices. In addition, the present study also helps to understand that whether MV phenomenon in diatoms is due to stress (especially climate change) or it is due to its natural tendency.