At the bottom of the food chain is the algae because its a plant. Next comes the Krill, which are more successful then humans. They eat algae but are eaten buy fish, penguins and other birds, seals, etc. Next would probably be fish or penguins because they eat the krill which eats the algae, but are eaten by seals. Seals are up next because they get eaten and killed by whales and other seals. Bears and whales are up at the top and although they are the best hunters, there are a lot fewer of them.