Polar Food Chains
Understand polar food chains: in the Antarctic, phytoplankton are eaten by krill, krill are eaten by fish and penguins, and penguins are eaten by leopard seals and orcas; in the Arctic, algae under ice feeds zooplankton, which feeds fish, which feeds seals, which feeds polar bears, and that tiny organisms like krill and plankton are the foundation of all polar life
What a learner can do afterwards
- Construct an Antarctic food chain: phytoplankton → krill → penguin → leopard seal or orca
- Construct an Arctic food chain: algae → zooplankton → fish → seal → polar bear
- Explain why krill and plankton are critical: without them, the entire food chain collapses
1 · Read
Every living thing needs food for energy, and in nature, food connects in a chain. One animal eats another, and that animal gets eaten by something bigger. At the icy poles, every chain starts with something so small you can barely see it.
In the Antarctic Ocean, tiny phytoplankton float near the surface and soak up sunlight. Small krill eat the phytoplankton by the billions. Fish and penguins eat the krill. Then leopard seals and orcas hunt the penguins. Each animal passes energy up to the next.
Under the Arctic ice, tiny algae grow and use sunlight to make food. Zooplankton eat the algae. Fish eat the zooplankton. Seals eat the fish. Polar bears hunt the seals on top of the ice. It is the same idea as the Antarctic chain, just with different animals.
Krill and plankton are tiny, but they hold up the whole chain. If they disappeared, penguins, fish, seals, and even polar bears and orcas would run out of food.
Every polar food chain starts with tiny plankton or algae, and every bigger animal depends on it.
More to read
Save the krill, save the world
Krill are tiny animals that look like little shrimps. They are very small, but they are some of the most important animals in the ocean. Giant whales, like humpback whales and blue whales, eat krill. Even though a whale is as big as a bus, it depends on these tiny creatures to live. In the cold waters near Antarctica, krill gather in huge groups in the summer. Whales travel very far to feast on them. Penguins, seals, and fish eat krill too. This means krill are like the bottom block of a tower. If you take away the krill, the whole tower falls down. The whales, penguins, and seals would have nothing to eat. So if we want to protect the biggest animals on Earth, we have to protect some of the smallest.
Data Puzzle: Tracing Carbon Through the Arctic Food Web
In the Arctic Ocean, tiny algae grow on and under the sea ice. These algae are like little food factories. They use sunlight to make their own food. Small animals called zooplankton eat the algae. Fish eat the zooplankton. Seals eat the fish. And polar bears eat the seals. This is called a food web, and the algae are at the very bottom of it. Scientists wanted to know what happens when the sea ice melts. They found a clever trick. Algae that live in open water and algae that live on ice make different kinds of fats. By looking at the fats inside an animal's body, scientists can tell which kind of algae its food ate. This helps them see how the whole Arctic food web is connected, from tiny algae all the way up to the polar bear.
Polar Bears: Climate Change Lesson
Every living thing in the Arctic is connected, like strands in a spider web. This is called the web of life. Algae and plankton make food from sunlight. Little fish and sea animals eat the plankton. Bigger animals eat the little ones. At the top sits the polar bear. When the climate warms up, the sea ice melts earlier. That changes life for the algae and plankton at the bottom of the web. Then the change travels up the web, to the fish, to the seals, and finally to the polar bears. In this lesson, students play a game with the web of life. They see how one small change can shake the whole web.
Explore more
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.