I just read an interesting article about krill. Yes, I such small creatures can actually sometimes be fascinating. The article talks about how Antarctic krill fertilize the Southern Ocean with iron. I knew krill were a key part of the food chain in Antarctica, as penguins and such eat them, but there role in the ecosystem is much more involved.
The new study shows that krill feed on decaying organisms on the sea floor and then release iron into the ocean as they return to the surface. This is new information in that krill were once thought to mainly stay on the surface, but the new study shows they regularly go down and feed on the sea floor. It also shows that krill play a role in improving the ocean's ability to store carbon dioxide and thus are part of the Southern Ocean's natural carbon cycle.
Further Info: "Antarctic krill help to fertilize Southern Ocean with iron"