What Kind of Animals Live in the Ocean?

Many different animals live in the ocean. The ocean extends over more than 70 percent of the earth's surface. Unfortunately, human beings are a non-aquatic life form so the majority of the wonders of the marine world go unseen. If we lived in the water, though, we would see the tallest mountains in the world, the deepest valleys and, most importantly,  the most varied and numerous collection of animal species.

It is impossible to accurately state the number of marine species that exist, but scientist have estimated a formidable number of over two million. This means that there are many different kinds of animals living in the ocean. The biggest animal on earth, the blue whale, is found in the ocean as well as some of the smallest organisms on earth (collectively called plankton).

Animals in the ocean vary in shape, size, color, living environment, type of food, and even breathing mechanisms. The majority of people could easily many name ocean dwellers including whales, dolphins, sharks. Some might even remember “Nemo” who was a clown fish, but most forget about the smaller, but just as amazing, prominent animals that share the marine habitat with these bigger ocean occupants.

Interesting Ocean Animals

Here is some information on just a few of some of the most interesting animals living in the ocean - tube worms, coral and jellyfish.

Tube Worms

Tube worms are fascinating creatures just because their habitat is in the ocean. As their name implies, they are tube-like shaped worms characterized by a red “plume” at their tip. As it turns out, the red plume is filled with blood and highly vascularized to optimize exchanging chemical compounds with the environment (which is how it gets its food).

The environment in which a tube worm lives is one of the most extreme on earth. Tube worms live near hydrothermal vents which are openings in the ocean floor where hotter-than-boiling water containing minerals spew out. As these vents are on the ocean floor, they are so deep underwater that it is utterly dark (there is no sunlight whatsoever), and there is a pressure so intense that the lungs of a human being would be instantly crushed.

However, these tube worms have a symbiotic relationship with the bacteria that live within them. Through the process of chemosynthesis, the bacteria convert the minerals in the water from the hydrothermal vents into usable energy supply for the tube worms. 

Coral

Corals exist in colonies as small sea anemone-like polyps, but they are most easily recognized as coral reef builders. It is a little known fact that the beautiful coral reefs that enthrall scuba divers and snorkelers around the world are actually skeletons of these organisms.

Reef building corals are characterized by having more than eight tentacles, and though they can feed on small fish and plankton using the stinging cells on their tentacles, they get most of their nutrients through a symbiotic relationship with zooxanthellae algae. It is this zooxanthellae that give coral reefs their amazing colors. As these algae are photosynthetic, the majority of coral reefs are found in shallower, clearer waters in which sunlight can easily penetrate.

Jellyfish

Jellyfish is a rather generic name for a group of free-swimming marine animals that have similar morphologies consisting of a bubble-shaped body and string-like tentacles. It encompasses almost 2000 different species from several different animal classes, but all under the phylum Cnidaria.

Jellyfish are found in every ocean, and at every depth, favoring neither the surface, nor the deep sea. Jellyfish are known to appear suddenly in large groups commonly referred to as blooms, or swarms, but these are actually a consequence of their natural life cycles.

Jellyfish are usually produced in the spring from benthic polyps that asexually bud to give rise to the familiar jellyfish form. However, it is important to note that the life cycle of the Jellyfish is a lot more convoluted and involves both asexual and sexual reproduction.

Furthermore, bloom formation is a complex process that depends on many variables such as ocean currents, oxygen concentrations, nutrients, and temperature. It is a fact that Jellyfish are becoming more populous in the ocean and besides the severe effects to fish in the area, they are also affecting people. Jellyfish carry an ominous reputation for their painful sting, which may, in rare cases, result in death.