Stunning Underwater Plants and Sea Life on the Ocean Floor

With over 1,000 species of sea anemone in the ocean, these creatures are responsible for some of the most stunning colors and shapes you'll find underwater. The white-plumed anemone can grow as high as three feet tall and thrives in cold water from Alaska to San Diego. And while the soft pouf at the top looks like a nice place for a fish nap, those tentacles are the anemone's primary tool for stinging and catching prey.

The bushy red sea whip is a soft coral in the order alcyonacea and the family Ellisellidae. Soft corals do not have the calcium carbonate skeletons found in hard corals. Each branch of the sea whip contains countless coral polyps (small tubes fringed with tentacles) that are responsible for bringing in food. Located primarily in shallow waters in the tropics and subtropics, these coral are found across the world. Like the red whip, corals of this family are usually brightly colored and come in a variety of shapes.

This vibrant green sea anemone bears a strong resemblance to the land-based Anastasia flower, a type of spider chrysanthemum. Most of the anemone’s color occurs due to the symbiotic relationship it has with the photosynthetic organisms that live in its tissues. Like other anemones, these attach themselves to hard surfaces — like rocks and coral reefs — to wait for fish that inadvertently swim into its stinging tentacles.

The vibrant hue of this lilac-looking purple coral isn't the only striking thing about it: Though the color is rare, acropora coral is one of the most plentiful types of coral. Acropora coral provides a habitat for fish and other sea life. These corals are also a reef-building species, which means they're often the first on the scene of a new reef, and they spread to provide homes for other corals.

Only one kind of fish is immune to the stings of the anemone, and, as anyone who has seen "Finding Nemo" can tell you, it’s the clownfish. Here, a bright orange and white clownfish hides among the grass-like tentacles of a sea anemone. Not all clownfish or all sea anemone are able to coexist, but for those that can, the relationship is beneficial to both creatures. The symbiotic process between the two is highly evolved, and involves the clownfish developing a thick mucus layer to protect it from the anemone’s powerful sting.

Despite its name, sun coral are a species of coral that don't require much sunlight. They are a deep water coral that make their homes in caves and other dark, underwater spaces. They get the energy they need (and their bright orange or yellow color) by feeding on zooplankton. They're also the only stony coral that set up permanent digs in the Caribbean after invading the ocean in the ballasts of ships coming from the coral's native ocean, the Indo-Pacific.

Some of these life forms appear more familiar than you'd expect. This kelp, for instance, looks like a leafy forest. Nutrient-rich kelp may show up on the beach as torn piles of seaweed, but underwater it has a whole different life. A type of brown algae, kelp can grow up to 18 inches per day and can reach depths of up to 131 feet. When scientists stumbled upon a kelp forest in the Pacific Ocean in 2007, the discovery highlighted how much we still have to learn about the world's waters: According to NPR, biologists had previously thought that kelp couldn't grow in warm tropical waters.

Feathery soft corals make up this bouquet of brightly-colored sea life. Soft coral are members of the Octocorallia subclass, named for their "eightfold radial symmetry," which means they have eight smaller pieces that branch off of each main tube to give the downy appearance. Soft coral, which have significant variation in shape and size, can thrive in deep water or shallow tropical water.

Open brain coral are found in the warm, shallow waters of the Red Sea, Indonesia, and the Australian archipelago. A type of stony coral, open brain coral are near threatened due to the reduction of coral reef habitat and harvesting for aquariums. This species of coral is small, less than 8 inches in size, and is both solitary and colonial, and may be found among other types of free-living coral.

Coral reefs are a diverse ecosystem teeming with remarkable creatures. But these detailed and dramatic landscapes are threatened by warming, pollution, and overfishing. The largest coral reef system in the world, the Great Barrier Reef, is in danger. One of the greatest threats to coral reefs globally is rising water temperature. Known as coral bleaching, this temperature increase causes a reduction in the amount of microscopic algae that produce the food corals need to survive, which can in turn can destroy coral or cause severe damage to their ecosystem.