CONICET | Buscador de Institutos y Recursos Humanos

I would like to make the point on the fuel of Antarctica: the krill. This is a shrimp like critter of 2 inches long, that is the most abundant on Earth, either if we weight them all together or if we count them. The Antarctic population of krill can reach a number followed by 14 zeros!! The krill serves as food for all the animals that we can see from a ship or a boat travelling to Antarctica: penguins, seals, whales, and flying birds (like albatrosses or petrels). Even those species that feed on seals or penguins, like the infamous leopard seal or the orca whales, depend indirectly on krill. The krill itself is a filter-feeder, has a special basket made of its 13 pairs of forelimbs, that allow it to grab a parcel of water, squeeze it, and retain the tiny, microscopical algae that is contained in the water. These algae are the plants of the sea, which from sunlight and minerals produce their own sugars that serve as food for themselves. During winter, when the day is very short and there is no enough sunlight for the algae to growth, the krill must search food somewhere else. This place is under the sea ice, where some algae are accumulated, and the krill -by scrapping the ice with their limbs- get their food. The sea ice begins to build up during fall, it covers the sea surface, and can reach 3 to 8 feet thick. The sea ice covers a surface of the Southern Ocean that doubles that of the United States, and melts down during summer. During the recent years, scientists have discovered that during the last 100 years the extension of the sea ice during winter has diminished and the number of krill so did. The global warming is one of the threats to the extension of the sea ice, and so to the number of krill, penguins, whales, seals, petrels, and all the Antarctic ecosystem.

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