Penguins Barometer for Ocean Health

Chinstrap penguin prancing on Prasiola crispa, a terrestrial green algae. (Ron Naveen/ OCEANITES)

Adélie penguin wing spread. (Ron Naveen/ OCEANITES)

Nesting Adélie penguins, Admiralty Bay. (Ron Naveen/ OCEANITES)

Penguin swimming, Antarctica. (John B. Weller)

Gentoo penguin headshot. (Ron Naveen/ OCEANITES)

Close up of fish below the Ross Sea. (John B. Weller, Courtesy of The Pew Charitable Trusts)

Close-up of krill. (Photo credit: grandfathered)

Below the Ross Sea. (John B. Weller)

Avalanche in the Lemaire Channel. (Ron Naveen/ OCEANITES)

Pods of killer whales, sometimes 100 strong, patrol the ice edges. Three separate ecotypes live in the Ross Sea, each specializing in a different diet. (John B. Weller)