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Most oceanic species (78 per cent, or 44 per cent of all fish species), live near the shoreline. These coastal fish live on or above the relatively shallow continental shelf. Only 13 per cent of all fish species live in the open ocean, off the shelf. Of these, 1 per cent are epipelagic, 5 per cent are pelagic, and 7 per cent are deep water. [16]
Marine biology studies species that live in marine habitats. Most of the Earth's surface is covered by ocean, which is the home to marine life. Oceans average nearly four kilometers in-depth and are fringed with coastlines that run for about 360,000 kilometres. [4] [5] Marine biology can be contrasted with biological oceanography.
The mass of this world ocean is 1.35 × 10 18 metric tons or about 1/4400 of Earth's total mass. The world ocean covers an area of 3.618 × 10 8 km 2 with a mean depth of 3682 m, resulting in an estimated volume of 1.332 × 10 9 km 3. [18]
Global biodiversity is the measure of biodiversity on planet Earth and is defined as the total variability of life forms. More than 99 percent of all species [1] that ever lived on Earth are estimated to be extinct. [2][3] Estimates on the number of Earth's current species range from 2 million to 1 trillion, but most estimates are around 11 ...
Marine ecosystems are the largest of Earth 's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply [1][2] and 90% of habitable ...
Species evenness [181] is the relative number of individuals of each species in a given area. Species richness [182] is the number of species present in a given area. Species diversity [183] is the relationship between species evenness and species richness. There are many ways to measure biodiversity within a given ecosystem.
The ocean is known to be the habitat of over 230,000 species, but may hold considerably more – perhaps over two million species. [18] Yet, the ocean faces many environmental threats, such as marine pollution, overfishing, and the effects of climate change. Those effects include ocean warming, ocean acidification and sea level rise.
Balaenoptera sibbaldii Sars 1875. The blue whale (Balaenoptera musculus) is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9 m (98 ft) and weighing up to 199 t (196 long tons; 219 short tons), it is the largest animal known ever to have existed. [a] The blue whale's long and slender body can be of various shades ...