Diatom studies three decades into the molecular age: a bibliometric analysis reveals genetic underexploration of diatoms compared to other taxa

Diatoms are among the most diverse and environmentally significant protists on Earth. Like many other organismal groups, a large portion of their diversity appears to lie beyond the resolution of the traditional light microscopy-based methods routinely and sometimes exclusively utilized in their investigation. Although the technological and conceptual developments in the fields of molecular biology and bioinformatics unlocked a remarkable opportunity to study diatoms in a previously unimagined depth and breadth, molecular diatomists anecdotally claim that diatoms remain genetically understudied compared to other taxa. However, this claim has never been quantified and rigorously tested. Therefore, we performed a bibliometric analysis of over 42,000 WoS-indexed diatom documents published in the past 35 years, between 1988 and 2023. The claim is confirmed: only ~15% of the analyzed diatom literature incorporated molecular data, about half compared to other groups, including other algae, cyanobacteria, plants, fungi, and animals. Interestingly, research for all groups seems to asymptotically saturate with molecular methods once they are used in about one-third of the documents annually, an observation which has important implications. In addition, past trends in the use of molecular data in diatomology were explored and some future ones were predicted.