Oceans and seas

Observed from space, our planet’s surface appears to be dominated by the color blue. This blue color occurs because of the presence of the oceans and seas of the world. These features cover approximately 71% or 361 million square kilometers (139 million square miles) of Earth’s surface with a volume of about 1370 million cubic kilometers (329 million cubic miles). The average depth of these bodies of seawater is about 3.8 kilometers (2.4 miles). Maximum depths can exceed 10 kilometers (6.2 miles) in areas known as ocean trenches. The oceans contain 97% of our planet's available water. The ocean is also home to many forms of life uniquely adapted to survive in this habitat. Humans have degraded the oceans and their life through pollution, overfishing, carbon dioxide acidification and resource exploitation.

  • Indigo hamlet Featured Article Indigo hamlet Indigo hamlet

    The indigo hamlet (scientific name: Hypoplectrus indigo) is a member of the grouper/seabass family (Family Serranidae) that live on coral reefs in the Western Atlantic Ocean... More »

  • Spinner dolphin Featured Article Spinner dolphin Spinner dolphin

    The Spinner dolphin (Stenella longirostris), a marine mammal in the family of oceanic dolphins,  gets its name from the spinning behavior it shows when it leaps out of... More »

  • Ocean acidification troubles Featured Article Ocean acidification troubles Ocean acidification troubles

    The seas in which corals and other calcifying species dwell are turning acidic, their pH slowly dropping as Earth's oceans acidify in response to increased carbon dioxide... More »

  • Marine biodiversity Featured Article Marine biodiversity Marine biodiversity

    Biodiversity is now commonly defined as the variety of life in genes, species and habitats. According to the definition of the Convention on Biological Diversity, biodiversity is... More »

  • Coccolithophores Featured Article Coccolithophores Coccolithophores

      Like any other type of phytoplankton, coccolithophores are one-celled marine plants that live in large numbers throughout the upper layers of the ocean. Unlike any... More »

  • Long-finned pilot whale Featured Article Long-finned pilot whale Long-finned pilot whale

    The long-finned pilot whale (scientific name: Globicephala melas) is one of two species in the genus Globicephala. The pilot whale is so named because when swimming, the groups... More »

  • Seas of the world Featured Article Seas of the world Seas of the world

    A sea is commonly defined to be an extended body of saline water associated with one of the worlds five oceans (Atlantic, Indian, Pacific, Arctic, and Southern oceans). Some seas... More »

Recently Updated
Northwestern Hawaiian Islands Marine National Monument Last Updated on 2014-07-23 19:37:23 The Northwestern Hawaiian Islands Marine National Monument is the single largest conservation area under the U.S. flag, and the largest marine conservation area in the world. It encompasses 137,792 square miles of the Pacific Ocean – an area larger than all the country's national parks combined. If they were laid atop the continental United States, the Northwest Hawaiian Islands (NWHI) would cover a distance equal to that between New York City and Omaha, or Boston and the Florida Everglades. The NWHI coral reefs are the foundation of an ecosystem that hosts more than 7,000 species, including marine mammals, fishes, sea turtles, birds, and invertebrates. Many are rare, threatened, or endangered. At least one quarter are endemic, found nowhere else on Earth. Many more remain unidentified or even unknown to science. Many of the islands and shallow water environments are... More »
Pinniped Last Updated on 2014-07-21 17:04:25 Pinnipeds ("finned-feet") are are group of marine mammals, that includes seals, sea lions, and walruses. The word pinniped is sometimes treated as a synonym for "seal" since all pinnipeds except for the the sole species of Walrus are seals (sea lions are eared seals).     Scientific Classification Kingdom: Animalia (Animals) Phylum:--- Chordata Class:------ Mammalia (Mammals) Order:-------- Carnivora (Carnivores) Family:-------- Otariidae (Eared seals) Pinnipeds differ form other marine mammals like whales, dolphins and porpoises in that they do not spend their entire lives in water. Pinnipeds "haul out" onto land and ice to mate, give birth, moult, and rest. Pinnipeds were agressively hunted until the early twentieth century for their skins, oil, meat and, in the case of... More »
Hawaiian Islands Humpback Whale National Marine Sanctuary Last Updated on 2014-07-10 16:22:15 The Hawaiian Islands Humpback Whale National Marine Sanctuary is one of 13 sanctuaries in the National Marine Sanctuary System created under the U.S. Marine Protection, Research and Sanctuaries Act. The sanctuary's goal is to promote comprehensive and coordinated management, research, education and long-term monitoring for the endangered humpback whale and its habitat. The Hawaiian Islands are the world's most isolated island archipelago, born of ancient volcanoes and inhabited by animals and plants derived from ancestors that found their way here over thousands of miles of ocean. According to scientists, the shallow, warm waters surrounding the main Hawaiian Islands constitute one of the world's most important habitats for the endangered humpback whale. Nearly two-thirds of the entire North Pacific population of humpback whales migrates to Hawai`i each winter. Here,... More »
Monterey Bay National Marine Sanctuary Last Updated on 2014-07-10 15:23:34 The Monterey Bay National Marine Sanctuary (MBNMS), designated in 1992, is a Federally-protected marine area offshore of California's central coast. Stretching from Marin to Cambria, the MBNMS encompasses a shoreline length of 276 miles and 5,322 square miles of ocean, extending an average distance of 30 miles from shore, extending from Rocky Point (just north of San Francisco's Golden Gate Bridge) to Cambria (just north of Morro Bay). At its deepest point, the MBNMS reaches down 10,663 feet (more than two miles). It is the USA's eleventh Marine Sanctuary and second only to the Northwestern Hawaiian Islands Marine National Monument in size—larger than Yosemite or Yellowstone National Parks. The MBNMS was established for the purpose of resource protection, research, education and public use. Its natural resources include the USA's largest kelp forest, one of... More »
Gray’s Reef National Marine Sanctuary Last Updated on 2014-07-08 18:36:18 Within the 17-square-nautical-mile sanctuary, there are both rocky ledges and sandy flat places. The reefs' rock ledges, submerged beneath 60 to 70 feet of water, can be as tall as 6-8 feet and are highly complex, with nooks and crannies that provide habitat for invertebrates and fishes to hide. The attached invertebrates form a dense carpet of living creatures that in places completely hides the rock. This feature gives the habitat of Gray's Reef its common name -- a "live bottom." Gray's Reef National Marine Sanctuary, designated in January 1981, is one of the largest near-shore live-bottom reefs in the southeastern United States. The sanctuary is located 32 kilometers (17.5 nautical miles) off Sapelo Island, Georgia and encompasses 58 square kilometers (17 sq. nautical miles) of live-bottom habitat. It is one of 13 marine sanctuaries that make up the... More »