February 1, 2016 — A man is poised with a crossbow on an inflatable Zodiac in the Weddell Sea, impressively keeping his balance as the tiny boat pitches in the Antarctic swells. He’s aiming at a killer whale that’s surfaced to breathe. Unlike his predecessors from long ago, he’s not trying to kill the whale. Rather, his crossbow is equipped with a satellite tracking device that he is attempting to attach to the whale’s dorsal fin.

The man is Dr. John Durban, and along with his partners Dr. Holly Fearnbach and Bob Pitman with the U.S. National Marine Fisheries Service, he is conducting research to understand the role of killer whales as top predators in the changing Antarctic ecosystem. With a grant from the Lindblad Expeditions-National Geographic (LEX-NG) Fund, this team of scientists makes annual expeditions to Antarctica to carry out their research.

While Antarctica tends to get a bad rap as a frozen wasteland, it’s actually a dazzling wilderness of ice and stone. Offshore, the Southern Ocean is chock full of marine life. Despite the frigid water temperatures—somewhere in the vicinity of 30℉…brrr!—an abundance of marine creatures exist as part of a robust food web.

At the bottom (of the web, not the ocean), is krill. This mini crustacean smaller than your pinky finger is the foundation of the Antarctic food chain. Species from minke whales to small fish, squid, and penguins dine on this shrimp-like creature. Bigger fish and seals eat the fish, squid, and penguins that eat the krill. And at the top of the web is the killer whale: a cunning and efficient predator.

Read the full story at National Geographic