Diatom Algae for Carbon Sequestration in Oceans

Diatom algae are responsible for about 20–25% of primary production on Earth. They are said to have evolved ~200 million years ago (mya). Diatoms have a unique feature—a silica exoskeleton, giving them an advantage over the other phytoplankton. Diatoms play a vital role in regulating the nitrogen cycle in oceans and freshwater bodies. However, anthropogenic activity has adversely impacted diatom production and water ecology over the past 250 years. Their production may have decreased by as much as 40% in the last 50 years. The invention of mechanized trawlers enabled fishing on an industrial scale since these trawlers and other support vessels could travel long distances and spend more days out in the ocean. Thus, fish stocks plummeted, which directly affected the diatom population. Growing diatom algae is also considered the best solution to eutrophication. Diatoms take in CO2 and nutrients like nitrogen and phosphorus, produce oxygen, and are also consumed by zooplankton and fish. Planting forests is considered a carbon sequestration solution. Similar is growing macroalgae in coastal waters. Diatoms in coastal waters keep it clean, enabling mangroves and sea grasses to grow. Dead diatoms sink to the depths of the ocean, together with other organic matter, and sequester carbon into the depths. This is called the ocean’s biological pump. However, growing microalgae/phytoplankton is currently not being considered as a valid carbon sequestration solution. What is required is a thorough research into the world of oceans to understand in further detail the role of diatoms in increased ocean productivity and carbon sequestration.