IN A LABORATORY beneath the long wings of the Australian Antarctic Division (AAD) in Hobart’s southern suburbs, krill biologist Rob King is lit by the glow of eight long tubes of radiant water. Each 120-litre tube, filled with billions of red or green Antarctic phytoplankton, gleams as luminously as traffic lights. If you didn’t know better, you might mistake them for sports drinks.
“They are sports drinks,” says King. “They’re sports drinks for krill.”
These tubes represent the largest volume of Antarctic phytoplankton outside the Southern Ocean. They’re a mesmerising sight, but the microscopic, single-celled plants aren’t here for their beauty. They’re here to feed the 40,000 Antarctic krill (Euphausia superba) that skitter about in tanks in the two adjoining rooms that make up the world’s largest krill aquarium.
Now, King skims a small aquarium net across the surface of one of the 2000-litre tanks, scooping up krill and checking their transparent carapaces for signs of eggs. In a way, he’s checking the future health of the Southern Ocean. These eggs are crucial to our understanding of Antarctic krill’s resilience against a changing planet – and Antarctic krill are pretty much crucial to everything about the Southern Ocean.
There, the food chain is typically short and simple. Antarctic krill feed on phytoplankton (and smaller amounts of zooplankton), while the ocean’s charismatic megafauna – baleen whales, seals and penguins – feed on krill. In a year, up to half of the Southern Ocean’s krill is devoured by other creatures; a blue whale alone might eat four tonnes of krill in a day. And yet the krill population routinely replenishes itself.
Such resilience and the weight of numbers might suggest an invincibility, but there are very real and familiar threats to this massive population. Studies have found that oceans absorb more than 30% of global carbon
