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Everything on Earth relies on something else to ensure its survival. The Arctic food chain is very complex with each marine organism relying on another to complete the chain. In Arctic coastal waters small organisms, known as diatoms, act as the primary producers for this food web of life.
Image: A microscopic look at Thalassiosira nordenskioeldii.
Why this species is important
Thalassiosira nordenskioeldii (its scientific name) is part of a group of diatoms upon which the entire marine planktonic Arctic food chain relies. These tiny living protists provide nutrients and food energy for other larger organisms that marine mammals such as whales and seals rely on for food.
The food web
The food web is an intricate chain in which all living things rely on something else to survive. The Arctic food web is one such chain.
This info graphic shows how just 1kg of a polar bear is reliant on a 10kg ringed seal. 1kg of a ringed seal's energy is based on it consuming 10kg of fish. 1kg of fish requires 10kg of zooplankton while to create 1kg of zooplankton relies on 10kg of phytoplankton.
Looking at this chain overall, to create 1kg of a polar bear requires an extraordinary 10,000kg of phytoplankton.
The single life
Diatoms reproduce sexually and asexually. Thalassiosira nordenskioeldii mainly grows in numbers asexually through mitosis, but during periods of stress can also reproduce sexually with the union of genetically unique cell forms.
A connecting chain
Thalassiosira nordenskioeldii cells contain threads that allow each individual to join to another, creating a bead-like chain. Under a microscope this chain resembles a necklace.
A floating colony
Each Thalassiosira nordenskioeldii contains long tubes called "portula" which house extra threads. These threads can be extended into the water allowing an entire colony to float.
Watch this video to learn more about plankton.
© Parafilms. Used under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0)
Transcript: Plankton life
Diatoms capture solar energy and produce a quarter of our planet's oxygen. Despite their tough, siliceous shells, these phytoplankton are abundant food for copepods and are at the base of the marine food chain.
Diatoms are single-celled organisms with nuclei and chloroplasts. They are protists living individually or forming chains, zig zags or spirals. The first diatoms – the centrics - appeared in the Jurassic age some 200 million years ago, as combinations of yeast-like organisms and algae. Over the eons, diatoms acquired new genes, shapes and complex metabolisms. They've become champions of photosynthesis, while retaining many properties of animal cells.
With other photosynthetic protists, they produce oxygen and absorb CO2. Over millions of years, diatom shells have sunk to the seabed, forming thick layers of silica and fossil fuels.
65 million years ago, diatoms survived the mass extinction of dinosaurs. They adapted to polar regions, where they still proliferate. Pennate diatoms appeared later and colonized new ecological niches. Some can glide over surfaces and congregate into a very thin layer called a biofilm. Pennates produce special metabolites and toxins that can ravage aquafarms.
When the sun shines, if iron and silica abound, diatoms flourish by dividing into smaller and smaller units. Survival demands that size be restored. Miniature diatoms transform into male and female gametes that join together and give birth to children much bigger than their parents.
Proliferation of diatoms at the poles result into explosive blooms visible from outerspace.