Study of diatoms started relatively late in comparison with most of the other groups of microorganisms. Diatoms have only been studied in an organised fashion for about 200 years, and the period of effective study has been about 150 years. Diatoms were first observed in 1703 by an unknown Englishman, published by “The Royal Society of London in the Philosophical Transactions”. Observing with a simple microscope the roots of the pondweed Lemna, he saw “adhering to them (and sometimes separate in the water) many pretty branches, composed of rectangular oblongs and exact squares." The description refers to the filamentous species of diatoms now known as Tabelleria and it is first written record of diatoms in the scientific community. There was much debate as to whether diatoms should be classified as plants or animals. Since plants were not supposed to move, the moving forms were often classified into the animal kingdom, while colonial forms and tube-dwelling types were thus classified into the plant kingdom. Upon greater accessibility of microscopes during the second half of the 19th century, diatoms, with their hard silica shells, great variety, and beauty, were well-suited specimens for scientific observation. Interest in diatoms soared as microscopists competed amongst themselves to resolve the finest details of diatom valves. In 1844, Kutzing published the Monograph of 1844 in which he classified all diatoms as algae. Most people in the scientific community followed suit, and disagreements about diatom classification disappeared. The close of the 19th century left us with a huge collection of diatom types collected throughout the world.

After the development of fully developed optical microscopes, the study of microorganisms in general, and diatoms in particular, attracted immense interest and attention of a number of productive workers. This grand period of exploration and description produced a very substantial, but poorly assimilated literature. Diatomists who worked towards the end of this grand period of growth produced remarkably advanced insights into cytology and similarly advanced theories of biological evolution (Mereschkowsky, 1903). Even though diatom study declined in the early 1900s due to the requirement of sophisticated microscopes, yet an amateur tradition of its study flourished in England and North America . The study of diatom extended throughout the world during the period of European colonialism and global exploration.

The history of ecological studies on diatom can be roughly classified into three eras. The first era is from 1830 to 1900 named as the “era of exploration”. During this time most research focused on diatoms as objects of study and more attention was given to the discovery of new taxa, their life cycle and basic physiological aspects. The second era is termed as the “era of systematisation”(1900-1970). During this period, most of the efforts were attempted to reduce the rich mosaic of information and inference concerning diatoms to more manageable dimensions. The origin of simple indices as a means of conveying information to managers and the public were developed in this era. The third and current era is the “era of objectification” (Stoermer and Smol, 1999). Thanks to the computational tools and multivariate statistics, which make it possible to determine the variables that affect diatom occurrence and growth, and more importantly, they are quantified, reproduced and measured with precision, which strengthen diatom ecology. In the course of time diatom have proven to be extremely powerful tools with which one can explore and interpret many ecological and practical problems.