Marine life, or sea life or ocean life, is the plants, animals and other organisms that live in the salt water of the sea or ocean, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. Marine organisms produce oxygen. Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land. The term marine comes from the Latin mare, meaning sea or ocean.
Most life forms evolved initially in marine habitats. By volume, oceans provide about 90 percent of the living space on the planet. The earliest vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians which spend portions of their lives in water and portions on land. Other fish evolved into land mammals and subsequently returned to the ocean as seals, dolphins or whales. Plant forms such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton forms the general foundation of the ocean food chain, particularly the phytoplankton which are key primary producers.
Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes as in mollusc siphons. Fish have gills instead of lungs, although some species of fish, such as the lungfish, have both. Marine mammals, such as dolphins, whales, otters, and seals need to surface periodically to breathe air.
A total of 230,000 documented marine species exist with some two million marine species yet to be documented. Marine species range in size from the microscopic, including plankton and phytoplankton which can be as small as 0.02 micrometres, to huge cetaceans (whales, dolphins and porpoises), including the blue whale – the largest known animal reaching 33 metres (108 ft) in length. Marine microorganisms, including bacteria and viruses, constitute about 70% of the total marine biomass.
The Clownfish, or Anemonefish, are the subfamily Amphiprioninae of the family Pomacentridae. There are currently 27 species, of which one is in the genus premnas and the rest are in the subfamily's type genus Amphiprion. The other pomacentrids are called damselfish.
Clownfish are native to wide ranges of the warm waters of the Pacific; some species ranges overlap others. Clownfish are not found in the Atlantic Ocean. Clownfish live in a mutual relationship with sea anemones, or in some case settle in some varieties of soft corals, or large polyp stony corals. Once an anemone or coral has been adopted, the clownfish will defend it vigorously.
However, clownfish in an aquarium environment can exist very well without an anemone (this may be advisable as most anemones are extremely difficult to keep alive even for experienced aquarists). The anemone is required in nature because reef life is dangerous for small, brightly coloured fish with very poor swimming abilities; in an aquarium lacking predators it is not needed. For this reason, clownfish never stray far from their host. In an aquarium, where they don't have to forage for food, it is very common for clownfish to remain within 6–12 inches of their host for an entire lifetime.
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Jacques-Yves Cousteau (11 June 1910 – 25 June 1997) was a French naval officer, explorer, ecologist, filmmaker, photographer and researcher who studied the sea and all forms of life in water. He co-developed the aqua-lung, pioneered marine conservation and was a member of the Académie française.
Cousteau was born in Saint André de Cubzac, France to Daniel and Elizabeth Cousteau on June 11, 1910 and died in Paris, France. He is generally known in France as le commandant Cousteau ("Commander Cousteau"). Worldwide, he was commonly known as Jacques Cousteau or Captain Cousteau.
Cousteau liked to call himself an "oceanographic technician". He was in reality a sophisticated lover of nature. His work permitted many people to explore the resources of the "blue continent".
His work also created a new kind of scientific communication, criticised at the time by some academics. The so-called divulgationisme, a simple way of sharing scientific concepts, was soon employed in other disciplines and became one of the most important characteristics of modern TV broadcasting.
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Did you know...
- Triggerfishes are the brightly coloured fishes of the family Balistidae. (pictured)
- The sea otter often keeps a stone tool in its armpit pouch.
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Photo credit: Tokugawapants
The Green Sea Turtle (Chelonia mydas) is a large sea turtle, the only member of the genus Chelonia (Brongniart, 1800). This turtle grows to 1-1.5 m in length, and can weigh 200 kg, making it the largest of the hard-shelled turtles. Its distribution extends throughout tropical, subtropical and some warmer temperate waters. Females lay their eggs on traditional nesting beaches, and the turtles often bask in the sand to warm their ectothermic bodies, but otherwise this species is entirely marine.
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