A Mini-Atlas of diatom frustule electron microscopy images at different magnifications

Diatom algae are active and efficient photosynthesizing single cell organisms responsible for a quarter of biomass and a quarter of oxygen release on the Earth surface. Diatoms form an enormously diverse class of microorganisms possessing stiff and strong, durable exoskeletons made from hydrated amorphous silica forming neat 3D nanostructures, and displaying hierarchical organization up to the scale of tens of micrometres. In our ongoing research into the structure and properties of diatoms we observed their colonization patterns on various surfaces, including polymers (PE, PP, PC and PETF) and silicon. This process can be guided by purposeful surface patterning to introduce pits, grooves, and ledges. Guided colonization opens the prospect of assembly and harvesting diatom frustules for applications in micro- and nano-electro-mechanical systems (MEMS and NEMS). Additionally, the wide range and specificity of diatoms opens the possibility of using them as tags and markers that are below the level of visibility by naked eye, but present specific spectroscopic fingerprints in visible light and UV ranges. Diatom ‘tags’ can also be read using high magnification imaging using Scanning Electron Microscopy (SEM). As a contributory guidance to morphological diversity of diatoms we present a mini-atlas of diatom in the form of high resolution SEM images.