Role of Diatoms in Water Quality Assessment and Environment
The diatoms are one of the prominent and ecologically most significant groups of organisms on the earth. They are unicellular, eukaryotic, photosynthesizing algae, having a siliceous skeleton and are found in all aquatic environments. The division Bacillariophyta is illustrious by the presence of an inorganic cell wall composed of silica (hydrated SiO2). The wall or frustule consists of two parts called “valves”. Diatoms have evolved to have detailed silica cell walls that reflect the types of habitat to which the particular species is adapted. Diatoms multiply rapidly, maintaining a dynamic population of varying size. They range in size between 20-200 microns in diameter or length in size, although sometimes they can be up to 2 mm long. The cell is solitary or colonial. They are non-motile or capable of only limited movement along a substrate and play ecological roles in producing diatomaceous earth and toxic blooms in surface waters.