Atlantic Ocean

is the world’s second largest ocean. Only the Pacific Ocean is bigger. The

Atlantic makes up about 26 percent of Earth’s ocean area and 17 percent of its total surface area. The Atlantic Ocean contains many special habitats for marine life. It is a rich source of seafood as well as other valuable resources.

Ocean life

A wide variety of plant and animal life thrives in the Atlantic Ocean. Plants and plantlike organisms can live only in the sunlit surface waters, to a depth of about 330 feet (100 meters). Animals live throughout the Atlantic.

Blue whale is the largest animal that ever lived. The blue whale reaches up to 100 feet (30 meters) long and can weigh over 150 short tons (135 metric tons). It has speckled blue-gray and white skin, relatively small, thin flippers, and a large, strong tail.

The blue whale strains food from the water using 260 to 400 thin, fringed plates called baleen, hanging from each side of its mouth. The whale eats primarily krill, a shrimplike animal. It lunges through masses of krill, taking in tons of water and food. It then closes its mouth and squirts the water out through the baleen, trapping the krill inside.

Killer whale, also called orca, is a large marine mammal known for its distinctive black and white coloring. The animal has a glossy black back, a mostly white underside, and a white oval patch near each eye. Adult males typically measure from 19 to 27 feet (6 to 8 meters) long and weigh 4 to 10 tons (3.6 to 9 metric tons). Females usually are somewhat smaller. Males have a dorsal fin on the back that

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stands up to 6 feet (1.8 meters) tall, more than twice the height of the female’s dorsal fin. The killer whale belongs to the marine dolphin family.

Killer whales rank among the most widely distributed mammals in the world. They occur in all oceans, typically in colder regions. Despite their wide distribution, killer whale populations remain small in most areas. Large populations occur in coastal waters of northwestern North America, northern Norway, Japan, and Iceland, as well as waters near Antarctica.

Orcas feed on fish, squids, and such marine mammals as dolphins, porpoises, seals, and whales. Different populations of orcas may eat different types of prey. In waters off northwestern North America, for example, populations known as residents feed mainly on salmon and other fish, but populations known as transients prey mostly on marine mammals. Orcas rarely attack people.

Killer whales often travel in groups called pods. Pods range from two to dozens of animals, usually consisting of several females and their young. In some cases, offspring of both sexes remain in a pod for life. New pods may form by splitting off from older, larger pods. Each pod communicates with its own set of underwater sounds, or dialect. Scientists believe each generation of a pod learns the dialect from the previous generation.

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