Diatomology

Diatomology is the scientific study of diatoms, a diverse group of unicellular algae within the division Bacillariophyta. Diatoms are characterized by their frustules, intricately patterned cell walls of hydrated silica that come in two halves and fit together like a microscopic shoe box.

Diatoms are traditionally split into centric and pennate forms. The frustule's ornamentation, including pores (striae) and the raphe system, provides key diagnostic features. Reproduction is primarily asexual by cell division, with occasional sexual reproduction to restore cell size. Diatoms require dissolved silicic acid for growth.

Diatoms inhabit oceans, rivers, lakes, and moist soils. They are major phytoplankton producers, contributing substantially to primary production and the global carbon cycle. Diatoms respond to nutrient availability, light, and silica supply and form seasonal blooms in many aquatic systems. They also fossilize well due to their silica shells.

Diatom fossils from silica deposits are important in paleoecology and biostratigraphy. Large deposits of diatomaceous earth, composed of fossil diatoms, are used commercially for filtration, polishing, and adsorbents.

Researchers study diatoms with light and scanning electron microscopy, often after oxidizing organic material with hydrogen peroxide or acids. Identification relies on valve morphology, striae patterns, and raphe structure. Diatom-based indices are used in water quality assessment.

Beyond ecology and paleontology, diatoms have applications in filtration, industrial abrasives, and as model organisms in evolutionary research, with emerging uses in nanotechnology and biomaterial science.