Portal:Marine life

The Marine Life Portal

Killer whales (orca) are highly visible marine apex predators that hunt many large species. But most biological activity in the ocean takes place among microscopic marine organisms that cannot be seen individually with the naked eye, such as marine bacteria and phytoplankton.

Marine life, 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, mostly microorganisms, produce oxygen and sequester carbon. Marine life in part shape and protect shorelines, and some marine organisms even help create new land (e.g. coral building reefs). Most life forms evolved initially in marine habitats. By volume, oceans provide about 90% 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 other algae grow in the water and are the basis for some underwater ecosystems. Plankton forms the general foundation of the ocean food chain, particularly phytoplankton which are key primary producers.

More than 200,000 marine species have been documented, and perhaps two million marine species are yet to be documented. Marine species range in size from the microscopic like phytoplankton, which can be as small as 0.02 micrometres, to huge cetaceans like the blue whale – the largest known animal, reaching 33 m (108 ft) in length. Marine microorganisms, including protists and bacteria and their associated viruses, have been variously estimated as constituting about 70%  or about 90%  of the total marine biomass. Marine life is studied scientifically in both marine biology and in biological oceanography. The term marine comes from the Latin mare, meaning "sea" or "ocean". (Full article...)

Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy. (Full article...)

Cscr-featured.png Recognized content - load new batch Symbol support vote.svg

Entries here consist of Good and Featured articles, which meet a core set of high editorial standards.

Selected article - show another


The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth, as illustrated on the right. The word "pelagic" is derived from Ancient Greek πέλαγος (pélagos) 'open sea'. The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes from the surface of the sea almost to the bottom. Conditions in the water column change with depth: the pressure increases; the temperature and amount of light decrease; the salinity and amount of dissolved oxygen (as well as micronutrients such as iron, magnesium and calcium) all change.

In addition to the above changes, marine life is affected by bathymetry (underwater topography) and by the proximity to land that is underwater such as the seafloor or a shoreline or a submarine seamount. Marine life is also affected by the proximity of the ocean surface, the boundary between the ocean and the atmosphere, which can bring light for photosynthesis but can also bring predation from above and wind stirring up waves and setting currents in motion. The pelagic zone refers to open and free waters in the body of the ocean that stretch between the ocean surface and the ocean bottom and are not too close to some boundary, like a shore or the seafloor or the surface. Marine life living in the pelagic zone can swim freely in any direction, unhindered by topographical constraints. (Full article...)
List of selected articles

Marine life images - load new batch

General images - load new batch

The following are images from various marine life-related articles on Wikipedia.

Did you know (auto-generated)

Nuvola apps filetypes.svg

More Did you know - load new batch

  • ... Shark skin is so rough that in the past it was used to make a type of sandpaper, called shagreen.
  • ... there are probably types of cetaceans that are as yet unknown. For example, the Longman's beaked whale is only known from skulls washed ashore in Somalia and Australia. It has never been seen alive!
  • ... Some sharks are so flexible, they can bend right around and touch their tails with their snouts.
  • ... The ear bone called the hammer (malleus) in cetaceans is fused to the walls of the bone cavity where the ear bones are, making hearing in air nearly impossible. Instead sound is transmitted through their jaws and skull bones.
  • ... the male narwhal's tusk can be up to 3 metres in length and weigh up to 10 kilograms.
  • ... In sand tiger sharks and several other species, the biggest, strongest pups eat the others while still inside their mother’s body.

Related portals


List articles

Symbol list class.svg


Category puzzle
Select [►] to view subcategories

Selected image

Photo credit: Mdf

The Double-crested Cormorant (Phalacrocorax auritus) is a North American member of the cormorant family of seabirds. Its name is derived from the Greek words phalakros (bald) and kora (raven), and the Latin auritus (eared). Folk names of this bird include Crow-duck, Farallon Cormorant, Florida Cormorant, lawyer, shag, and Taunton turkey.

More on the Double-crested Cormorant

Cscr-featured.png See also Symbol support vote.svg

Associated Wikimedia

The following Wikimedia Foundation sister projects provide more on this subject:






Learning resources





Have a look at the Marine life WikiProject and sign up.

Here are some tasks you can do, as organized by The Marine life Wikiproject:


Purge server cache