diatomas

Diatomas is a term that in some contexts refers to diatoms, a major group of microalgae found in aquatic environments. The word can appear as an alternate spelling or transliteration in older literature or non-English sources. In modern scientific usage, the standard term for these organisms is diatoms.

Diatoms are unicellular or colonial algae characterized by their unique silica cell walls, called frustules, which fit together like a petri dish. The frustule is often ornamented with intricate patterns of pores and ridges, and its morphology varies widely among species, producing shapes such as disks, needles, and needles with ornate apices. Most diatoms are photosynthetic and contain chlorophyll a and fucoxanthin, contributing significantly to primary production in aquatic ecosystems. They range from freshwater to marine environments and can be free-floating or attached to surfaces.

Ecologically, diatoms play a central role in nutrient cycling and carbon fixation. They require silicic acid to build their frustules, and their rapid growth can lead to seasonal blooms that influence food webs. Diatoms also contribute to sediment formation; when they die, their silica shells accumulate on the bottom, forming deposits that can persist for millions of years.

Reproduction in diatoms occurs primarily asexually through cell division, with a size reduction over generations, followed by periodic sexual reproduction to restore cell size. Diatoms have a long fossil record and are valuable in paleolimnology and paleoceanography, where they help reconstruct past environmental conditions. They are also exploited commercially for filtration, polishing, and as a stabilizing or abrasive material.