On the sea ice near the Dumondville expedition station in east Antarctica, there are some ice-covered saline tendrils and the cold "pillars of death" in the picture. Because the sea water is salty, it looks like a full sponge when it freezes. Supercooled, high-density brine escapes from the ice, freezes the less salty water, becomes trapped, and then continues to descend and freeze again, thus forming a temporary and rare phenomenon.
Emperor penguins dive into the wider ocean in search of food. The brown patches above them are microalgae attached to the sea ice, which cling to the sea ice and begin photosynthesis in the spring.
A hundred feet below the ice, a sea lily waved its forelimbs, groping for particles of food. It is an animal, arguably a cousin of starfish, and it can swim. They have up to 20 wavy arms and can grasp floating food particles.
The purple-blue lid jellyfish is a bioluminescent crown jellyfish, about 14 inches (about 35 centimeters) wide, floating at a depth of 130 feet (about 40 meters), shining with a tail and a dozen barbed tentacles. These bell-shaped plankton cannot be exposed to direct sunlight or it will cause their death.
A curious Weddell seal, just a few weeks old, is swimming toward the camera, captured in close-up. Marine biologist Pierre Chevaldonné says it may be its first swim. The Weddell seal is one of all mammals that live and breed at the southernmost tip.
A diver looks at an emperor penguin while swimming nearby.
One of the 16 species of octopus in Antarctica lives on the ocean floor. All Antarctic octopus have a special pigment in their blood that turns them blue, helping them survive in temperatures below freezing.
Divers dive to 230 feet (about 70 meters) below sea level for nearly five hours each time, and then record the colorful life of the flora and fauna in the ocean.
A Weddell's seal swims under the ice. They all stay near the coast, breathing in the air on the ice through holes in the ice floes.
A young Weddell's seal is sitting in an ice gap thinking about life. They can grow up to 10 feet (about 3 meters) long at a young age and weigh up to half a ton when they reach adulthood.
A diver swims 200 feet (about 61 meters) below the surface of the water, where the light is dim and the temperature is below 29 degrees Fahrenheit (about minus 2 degrees Celsius).
The frozen waters beneath Antarctica are also home to a variety of marine invertebrates.
A seal swims under sea ice near Dumondville Station in Antarctica.
A diver is swimming under antarctic ice several feet thick. They used the rope that hung nearby to find their way back to the ground.
The orange sea squirt looks super simple in construction, like a sponge. They are chained to the ocean floor 200 feet below, siphoning (taking advantage of the difference in liquid level) food in the water, but they actually evolved well and belong to invertebrates. Although the juvenile orange sea squirt has a spinal cord.
Extreme conditions breed extreme animals. In the sea below 165 feet (about 50 meters), the light is dim. This 3-inch (about 8 cm) long Antarctic scallop may have been growing for decades, but it grew extremely slowly in extreme cold conditions.
This isopod looks a bit like a small pill that rolls up when threatened. But it's actually nearly 5 inches (about 13 centimeters) long.
At depths of 30 to 50 feet (about 9 to 15 meters), there is a forest of kelp with leaves over 10 feet (about 3 meters) long. Further afield, there are giant starfish up to 15 inches (about 38 centimeters) in diameter, which are much larger than their counterparts living in warm oceans. Starfish nestled on top of a tree sponge? Oh, it's more than 1 foot (about 30 centimeters) wide.
Sea spiders are another example of mysterious "polar gigantism". They are arthropods, like insects and spiders on land, and they can be found in all the oceans of the world, but rare in warm waters, and are smaller and almost invisible to the naked eye. Just like in the Arctic, sea spiders in antarctica can span 1 foot (about 30 centimeters) or more with one foot. In Antarctica, its legs alone are 7 inches (about 18 centimeters) long. But because their bodies are so small, their internal organs have stretched and grown into their legs.
The Weddell seal is swimming under the ice with her child. When the baby seals grow up, they can catch up with their mother's size.
The silverfish is carefully hidden in seaweed forests, and the inhabitants of these deep oceans have antifreeze protein in their blood, which helps them fend off temperatures below 29 degrees Fahrenheit (about minus 2 degrees Celsius). In the cold waters of Antarctica, there are at least 50 species of silverfish.
The body of the anemone clings to the ice floes, and the tentacles reach out into the dark water and sway, appearing sharp and bright. Marine biologist Marymegan Daly says it's the only known species of anemones living in ice, and it's unclear why they cross the ice or survive under the ice.
An octopus is moving at full speed on the Antarctic seabed. Antarctica has at least 16 species of octopus. They all have a special pigment in their blood called hemoglobin, which turns blood blue and helps them survive low temperatures.