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.
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, and particularly phytoplankton, are key primary producers forming the general foundation of the ocean food chain.
Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes (see insect and mollusc siphons) and gills. 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. Some amphibians are able to absorb oxygen through their skin.
A total of 230,000 documented marine species exist, including about 20,000 species of marine fish, 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 up to 33 metres (108 ft) in length. Marine microorganisms, including bacteria and viruses, constitute about 70% of the total marine biomass.
Giant squid, once believed to be mythical creatures, are squid of the Architeuthidae family, represented by as many as eight species of the genus Architeuthis. They are deep-ocean dwelling animals that can grow to a tremendous size: recent estimates put the maximum size at 10 meters (34 ft) for males and 13 meters (44 ft) for females from caudal fin to the tip of the two long tentacles (second only to the Colossal Squid at an estimated 14 meters (46 ft), one of the largest living organisms).
The mantle length, though, is only about 2 meters (7 ft) in length (more for females, less for males), and the length of the squid excluding its tentacles is about 5 meters (16 ft). There were reported claims of specimens of up to 20 meters (66 ft), but none had been scientifically documented.
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Nicholai Nicholaevich Miklukho-Maklai (Николай Николаевич Миклухо-Маклай in Russian) (1846 – 1888) was a Russian ethnologist, anthropologist and biologist.
Miklukho-Maklai was born in a temporary workers camp near Novgorod, a son of a civil engineer working on the construction of the Moscow-Saint Petersburg Railway. He attended a grammar school in Saint Petersburg, then went on to study at St. Petersburg University.
He travelled and studied widely in Europe, and became a close friend of the biologist Anton Dohrn, with whom he helped conceive the idea of "research stations" while staying with him at Messina, Italy.
Miklukho-Maklai left St Petersburg for Australia on the schooner Vityaz. He arrived in Sydney on 18 July, 1878. A few days after arriving, he approached the Linnean Society and offered to organise a zoological centre. In September 1878 his offer was approved. The centre, known as the Maritime Biological Centre, was constructed by prominent Sydney architect, John Kirkpatrick. This was the first marine biological research institute in Australia.
He visited Papua New Guinea on a number of occasions, and lived amongst the native tribes, writing a comprehensive treatise on their way of life and customs.
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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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