Antarctic Food Chain: From Phytoplankton to Apex Predators

1. Phytoplankton – Microscopic algae; primary producers (photosynthesis).
2. Zooplankton (copepods, etc.) – Eat phytoplankton.
3. Antarctic Krill (Euphausia superba) – Swarm in billions; eat zooplankton; keystone species.
4. Mid-Level Consumers: Fish (icefish, toothfish), squid, small seabirds – eat krill.
5. Apex Predators:
   • Baleen Whales (blue, humpback, minke) – filter-feed krill.
   • Seals (crabeater, leopard, Weddell, Ross) – eat krill, fish, penguins.
   • Penguins (Adélie, emperor, chinstrap, gentoo) – eat krill, fish.
   • Albatrosses & Petrels – scavenge, hunt squid/fish/krill.
   • Orcas (Killer Whales) – top predators; eat seals, penguins, whales, fish.

The system is fragile; krill decline from climate change or overfishing would cascade through the entire web.