Diatoms – the jewels of the ocean

Diatoms are unicellular microscopic algae, with cell walls consisting of silicon dioxide. The cell wall has a very specific pattern of tiny pores, allowing exchange of nutrients and waste products. Each pattern is species specific. It is no surprise that diatoms are referred to as ocean jewels.

Fossils indicate that diatoms have existed for at least 200 million years. The number of diatom species is estimated to around 20 000 – 2 000 000. New species are continuously identified and described.

Place in the ecosystem

Our every fourth breath of oxygen comes from diatoms. They form the basis of the food web and are eaten by everything from the size of microscopic ciliates to large whales.

Where to be found

Diatoms are to be found everywhere where there is moist and some available light: in the ocean, on the seabed, in lakes, in and on ice – even on cave walls!

Physiology

Diatoms photosynthesize, but they are also able to uptake small organic molecules. Thus, they can survive in darkness without forming resting stages. Diatoms contain chlorophyll a and c and, in addition, different carotenoids such as fucoxanthin, which give them a brownish colour. They store energy in the form of oil (lipids) and a carbohydrate called chrysolaminarin.

At the service of humans

The frustules of the algae have one to three layers of nanopores, which can be used in several industrial applications. Within Swedish Algae Factory we are currently focusing on their use to increase the efficiency of solar panels. The oil produced by diatoms is excellent as a source for biodiesel. The content of polyunsaturated fatty acids make them interesting as food supplements.

When diatoms grow (increase in number), they capture carbon dioxide, nitrogen and phosphorous, thus, our algae cultures become a perfect combination of a trap of greenhouse gases and waste water treatment.