What Are Diatoms?

Ecologically, Diatoms are the most significant groups of organisms on Earth. They are a major group of microalgae and live almost everywhere including oceans, rivers, lakes, damp rock surfaces, bogs and anywhere there is water. Living diatoms generate 20% of the oxygen that is produced on the planet in one year. Diatoms also consume around 6.7 billion metric tons of silicon every year from the waters they exist in. 

Diatoms are unicellular, which means that they are also extremely tiny in size. They are known to occur as solitary cells or colonies. These colonies can be in the shapes of ribbons, zigzags or stars. With adequate sunlight and nutrition, diatoms double every 24 hours, while every cell’s maximum life span is around six days.

Just like plants, diatoms use photosynthesis to convert light energy into chemical energy. This energy, in turn, helps other water organisms to survive. 

Diatoms are the most common type of plankton and are also called phytoplankton. According to fossil evidence, diatoms originated around 150 to 200 million years ago, i.e. before or during the early Jurassic period.

Diatoms are important because:

  • They are a major source of the oxygen found in our atmosphere and are responsible for 20 to 30% of the carbon fixation on the earth.
  • They provide the basis of the food chain for both freshwater and marine micro-organisms.
  • They can act as an environmental indicator of climate change.
  • They form the basis of household goods like pest prevention.
  • They tell us about the biotic condition of the water.

Diatoms are used to monitor past and present environmental conditions, especially the changes in the water quality over time. Diatomite—a collection of diatom shells found in the earth’s crust—is used for various purposes including water filtration, in cat litter, as a dynamite stabilizer and as a mild abrasive.

Diatomic Elements/ Molecules:

Diatomic Molecules

Diatomic molecules are molecules composed of two atoms of chemical elements. There are two types of Diatomic molecules: Homonuclear Diatomic molecules and Heteronuclear Diatomic molecules. When a diatomic molecule contains two atoms of the same element, it is called homonuclear. On the other hand, if a diatomic molecule consists of atoms of two different elements, then it is called heteronuclear.

There are hundreds of diatomic molecules that have been identified in the Earth’s environment, in interstellar space, and in the laboratory. Two species of diatomic molecules i.e. oxygen and nitrogen make up almost 99% of our atmosphere. On the other hand, hydrogen is the most abundantly found diatomic molecule in the whole universe.

A List of Diatomic Elements

The elements that form diatomic molecules at room temperature are:

  • Hydrogen.

Hydrogen is found in a large quantity in the overall makeup of the universe.

  • Oxygen.

Oxygen is present in the Earth’s as well as the Universe’s atmosphere.

  • Nitrogen

Nitrogen is the most abundantly found element in the Earth’s atmosphere.

And the halogens:

  • Chlorine.

Chlorine is a yellow-green colored element that exists as a gas at room temperature.

  • Fluorine.

Fluorine is a pale gas that has a sharp odor. It is also highly toxic.

  • Iodine.

Iodine exists as a purple-black solid at room temperature. When heated, it turns into a diatom.

  • Bromine.

Bromine is a red-brown liquid at room temperature. Similar to Iodine, it turns into a diatom when heated.

The noble gases are monatomic i.e. they rarely form molecules at all.

Diatomic Compounds

Some compounds like hydrogen chloride, carbon monoxide, and nitric oxide have diatomic molecules. These compounds are called heteronuclear since their atomic nuclei come from different elements.

High Temperature

Some elements form diatomic molecules once they’re heated long enough to turn into gas. The prefix ‘di-’ is added to the name of an element to signify its diatomic phase. For example, when the lithium gas forms a diatomic molecule, it is called dilithium. 

Other elements that form diatomic molecules when turned into gases are tungsten, sulfur, and carbon. Ionic compounds like sodium chloride can also become diatomic molecules when turned into gas.

These elements can only form diatomic molecules when they’re turned into gases. Once they cool down, they repolymerize.

Low Temperature

Diatomic molecules that are gases at room temperature remain diatomic even when the temperature is low enough to turn them into liquids. 

In conclusion, some of the most common elements found on earth and its atmosphere are diatomic molecules.

Commercial Use Of Diatoms

Dead diatom cells at the bottom of a lake bed or sea get mixed with organic matter and clay. When this sediment is exposed, it forms a mineral called Diatomite.

  • Diatomite is commercially used in a lot of ways. It is found in drinking water filters as well as in swimming pools. On the other hand, it is also present in nail polish and car paint. 
  • Diatomite can also be used to clean up toxic spills as well as an important component of cat litter. 
  • In buildings and auditoriums, Diatomite is used as insulation and it is also used for soundproofing.
  • Diatomite is also used as a pesticide because it absorbs all the water from the outer layer of insects.
  • Diatoms are also found useful in forensic science. The presence of diatoms in particular parts of a drowned person’s body helps the pathologist determine whether they were alive or dead while drowning.
  • Glass covers made from Diatoms are extremely good at capturing the sunlight. Therefore, they are used to increase the efficiency of solar energy cells.
  • Diatomite is extremely porous and hence is used to filter a variety of liquids from beer and wine to oil and drinking water.
  • Diatomite is also added to soil to make it less soggy or to loosen hard soil. It helps water and air to permeate through the soil, thus promoting plant growth.
  • Diatomite is also used as an important ingredient in dental fillings.
  • Diatomite is also used in hair, skin and nail products as a thickening agent as well as for high amounts of silica.


What do Diatoms eat?

Most Diatoms use the process of photosynthesis in order to produce their food. Though there are some diatoms that may rely on the nutrients floating in the water for their survival.

How do Diatoms move?

Most Diatoms do not move much in their lifetime, though a type of Diatom called Pennales is known to move in a gliding motion in the water.