They’re only a few centimetres long but krill are among the most abundant and ecologically crucial animals on Earth. Swarms of these shrimp-like crustaceans feed the ocean’s greatest creatures and play a surprising role in regulating our climate.
Life at the Heart of Ocean Food Webs
Krill are primary consumers they feed on phytoplankton converting tiny marine plants into protein-rich food for everything from fish and squid to penguins seals and whales. In the Southern Ocean alone Antarctic krill form massive swarms visible from space with densities of up to 30000 individuals per cubic metre.
Feeding the Giants
Blue whales the largest animals ever eat up to 4 tonnes of krill daily during feeding seasons. Without krill whales would starve seals and penguins would dwindle and marine food webs would collapse.
Climate Heroes
Krill contribute to the biological carbon pump by consuming phytoplankton and excreting carbon-rich waste that sinks to the seafloor they help sequester CO₂ from the atmosphere. This process locks away millions of tonnes of carbon each year helping stabilise Earth’s climate.
Under Threat
Commercial krill fisheries harvest krill for omega-3 supplements and aquaculture feed. Overfishing combined with climate-driven sea ice loss, which krill depend on during early life stages, threatens their populations. A decline in krill would ripple through the Antarctic ecosystem.
Why Krill Matter
As marine biologist Dr Nicol Stephen says “Krill are the linchpins of the Southern Ocean. Protecting them means protecting countless species and the ocean’s role in climate regulation”
