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Marine biology

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Title: Marine biology  
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Marine biology

Two views of the ocean from space
Only 29 percent of the Earth's surface is land. The rest is ocean, home to marine life. The oceans average nearly four kilometres in depth and are fringed with coastlines that run for 360,000 kilometres.[1][2]

Marine biology is the scientific study of organisms in the biology is the study of the organisms themselves.

A large proportion of all phytoplankton and zooplankton to huge cetaceans (whales) 30 meters (98 feet) in length.

Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support

  • Smithsonian Ocean Portal
  • Marine Conservation Society
  • Marine biology at DMOZ
  • Marine Ecology - an evolutionary perspective
  • Free special issue: Marine Biology in Time and Space
  • Creatures of the deep ocean – National Geographic documentary, 2010.
  • Exploris. [1]

External links

  • Morrissey J and Sumich J (2011) Introduction to the Biology of Marine Life Jones & Bartlett Publishers. ISBN 9780763781606.

Further references

  1. ^ Charette, Matthew; Smith, Walter H. F. (2010). "The volume of Earth's ocean". Oceanography 23 (2): 112–114.  
  2. ^ World The World Factbook, CIA. Retrieved 13 January 2014.
  3. ^ Oceanographic and Bathymetric Features Marine Conservation Institute. Uploaded 18 September 2013.
  4. ^ Foley, Jonathan A.; Karl E. Taylor, Steven J. Ghan (1991). "Planktonic dimethylsulfide and cloud albedo: An estimate of the feedback response". Climatic Change 18 (1): 1.  
  5. ^ Sousa, Wayne P (1986) [1985]. "7, Disturbance and Patch Dynamics on Rocky Intertidal Shores". The Ecology of Natural Disturbance and Patch Dynamics. eds. Steward T. A. Pickett & P. S. White. Academic Press.  
  6. ^ "History of the Study of Marine Biology - MarineBio.org". MarineBio Conservation Society. Web. Monday, March 31, 2014.
  7. ^ "A Brief History of Marine Biology and Oceanography". Retrieved 31 March 2014. 
  8. ^ Ward, Ritchie R. Into the ocean world; the biology of the sea. 1st ed. New York: Knopf; [distributed by Random House], 1974: 161
  9. ^ Gage, John D., and Paul A. Tyler. Deep-sea biology: a natural history of organisms at the deep-sea floor. Cambridge: Cambridge University Press, 1991: 1
  10. ^ Maienschein, Jane. 100 years exploring life, 1888-1988: the Marine Biological Laboratory at Woods Hole. Boston: Jones and Bartlett Publishers, 1989: 189-192
  11. ^ Anderson, Genny. "Beginnings: History of Marine Science". 
  12. ^ http://www.fishbase.org
  13. ^ http://www.worldwatch.org/node/784
  14. ^ Stidworthy J. 1974. Snakes of the World. Grosset & Dunlap Inc. 160 pp. ISBN 0-448-11856-4.
  15. ^ Sea snakes at Food and Agriculture Organization of the United Nations. Accessed 7 August 2007.
  16. ^ Hyde, K.D.; E.B.J. Jones, E. Leaño, S.B. Pointing, A.D. Poonyth, L.L.P. Vrijmoed (1998). "Role of fungi in marine ecosystems". Biodiversity and Conservation 7 (9): 1147–1161.  
  17. ^ Kirk, P.M., Cannon, P.F., Minter, D.W. and Stalpers, J. "Dictionary of the Fungi". Edn 10. CABI, 2008
  18. ^ Hyde, K.D.; E.B.J. Jones (1989). "Spore attachment in marine fungi". Botanica Marina 32: 205–218.  
  19. ^ San-Martín, A.; S. Orejanera, C. Gallardo, M. Silva, J. Becerra, R. Reinoso, M.C. Chamy, K. Vergara, J. Rovirosa (2008). "Steroids from the marine fungus Geotrichum sp". Journal of the Chilean Chemical Society 53 (1): 1377–1378. 
  20. ^ Suttle, C.A. (2005). "Viruses in the Sea". Nature 437 (9): 356–361.  
  21. ^ NOAA (1998) Record-breaking coral bleaching occurred in tropics this year. National Oceanic and Atmospheric Administration, Press release (October 23, 1998).
  22. ^ ICRS (1998) Statement on Global Coral Bleaching in 1997-1998. International Coral Reef Society, October 15, 1998.
  23. ^ Bryant, D., Burke, L., McManus, J., et al. (1998) "Reefs at risk: a map-based indicator of threats to the world's coral reefs". World Resources Institute, Washington, D.C.
  24. ^ Goreau, T. J. (1992). "Bleaching and Reef Commumity Change in Jamaica: 1951 - 1991". Amer. Zool. 32: 683–695.  
  25. ^ Sebens, K. P. (1994). "Biodiversity of Coral Reefs: What are We Losing and Why?". Amer Zool 34: 115–133.  
  26. ^ Wilkinson, C. R., and Buddemeier, R. W. (1994) "Global Climate Change and Coral Reefs:Implications for People and Reefs". Report of the UNEP-IOC-ASPEI-IUCN Global Task Team on the Implications of Climate Change on Coral Reefs. IUCN, Gland, Switzerland.
  27. ^ Seven Miles Down: The Story of The Bathyscaph Trieste., Rolex Deep Sea Special, January 2006.

References

Lists

See also

Most ocean life breeds in specific places, nests or not in others, spends time as juveniles in still others, and in maturity in yet others. Scientists know little about where many species spend different parts of their life cycles. For example, it is still largely unknown where sea turtles and some sharks travel. Tracking devices do not work for some life forms, and the ocean is not friendly to technology. This is important to scientists and fishermen because they are discovering that by restricting commercial fishing in one small area they can have a large impact in maintaining a healthy fish population in a much larger area far away.

An active research topic in marine biology is to discover and map the life cycles of various species and where they spend their time. Marine biologists study how the ocean currents, tides and many other oceanic factors affect ocean life forms, including their growth, distribution and well-being. This has only recently become technically feasible with advances in GPS and newer underwater visual devices.

Distribution factors

Marine life also flourishes around seamounts that rise from the depths, where fish and other sea life congregate to spawn and feed. Hydrothermal vents along the mid-ocean ridge spreading centers act as oases, as do their opposites, cold seeps. Such places support unique biomes and many new microbes and other lifeforms have been discovered at these locations .

In general, the deep sea is considered to start at the aphotic zone, the point where sunlight loses its power of transference through the water. Many life forms that live at these depths have the ability to create their own light known as bio-luminescence.

Other notable oceanic trenches include Monterey Canyon, in the eastern Pacific, the Tonga Trench in the southwest at 10,882 m (35,702 ft), the Philippine Trench, the Puerto Rico Trench at 8,605 m (28,232 ft), the Romanche Trench at 7,760 m (25,460 ft), Fram Basin in the Arctic Ocean at 4,665 m (15,305 ft), the Java Trench at 7,450 m (24,440 ft), and the South Sandwich Trench at 7,235 m (23,737 ft).

The deepest recorded oceanic trench measured to date is the Mariana Trench, near the Philippines, in the Pacific Ocean at 10,924 m (35,840 ft). At such depths, water pressure is extreme and there is no sunlight, but some life still exists. A white flatfish, a shrimp and a jellyfish were seen by the American crew of the bathyscaphe Trieste when it dove to the bottom in 1960.[27]

Deep sea and trenches

The open ocean is relatively unproductive because of a lack of nutrients, yet because it is so vast, in total it produces the most primary productivity. Much of the aphotic zone's energy is supplied by the open ocean in the form of detritus.

Open ocean

Much attention in marine biology is focused on coral reefs and the El Niño weather phenomenon. In 1998, coral reefs experienced the most severe mass bleaching events on record, when vast expanses of reefs across the world died because sea surface temperatures rose well above normal.[21][22] Some reefs are recovering, but scientists say that between 50% and 70% of the world's coral reefs are now endangered and predict that global warming could exacerbate this trend.[23][24][25][26]

Reefs comprise some of the densest and most diverse habitats in the world. The best-known types of reefs are tropical coral reefs which exist in most tropical waters; however, reefs can also exist in cold water. Reefs are built up by corals and other calcium-depositing animals, usually on top of a rocky outcrop on the ocean floor. Reefs can also grow on other surfaces, which has made it possible to create artificial reefs. Coral reefs also support a huge community of life, including the corals themselves, their symbiotic zooxanthellae, tropical fish and many other organisms.

Reefs

Shore habitats span from the upper intertidal zones to the area where land vegetation takes prominence. It can be underwater anywhere from daily to very infrequently. Many species here are scavengers, living off of sea life that is washed up on the shore. Many land animals also make much use of the shore and intertidal habitats. A subgroup of organisms in this habitat bores and grinds exposed rock through the process of bioerosion.

Intertidal zones, those areas close to shore, are constantly being exposed and covered by the ocean's tides. A huge array of life lives within this zone.

Tide pools with sea stars and sea anemone in Santa Cruz, California

Intertidal and shore

Marine habitats can be modified by their inhabitants. Some marine organisms, like corals, kelp and seagrasses, are ecosystem engineers which reshape the marine environment to the point where they create further habitat for other organisms.

Alternatively, marine habitats can be divided into demersal fish. Pelagic habitats are intrinsically shifting and ephemeral, depending on what ocean currents are doing.

Marine habitats can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends from the shoreline to the edge of the continental shelf. Most marine life is found in coastal habitats, even though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf

Marine habitats

cnidarians, ctenophores, chaetognaths, molluscs, arthropods, urochordates, and annelids such as polychaetes. Many larger animals begin their life as zooplankton before they become large enough to take their familiar forms. Two examples are fish larvae and sea stars (also called starfish).

The role of phytoplankton is better understood due to their critical position as the most numerous primary producers on Earth. Phytoplankton are categorized into cyanobacteria (also called blue-green algae/bacteria), various types of algae (red, green, brown, and yellow-green), diatoms, dinoflagellates, euglenoids, coccolithophorids, cryptomonads, chrysophytes, chlorophytes, prasinophytes, and silicoflagellates.

Microscopic life undersea is incredibly diverse and still poorly understood. For example, the role of viruses in marine ecosystems is barely being explored even in the beginning of the 21st century.[20]

A copepod.

Microscopic life

Plants that survive in the sea are often found in shallow waters, such as the seagrasses (examples of which are eelgrass, Zostera, and turtle grass, Thalassia). These plants have adapted to the high salinity of the ocean environment. The intertidal zone is also a good place to find plant life in the sea, where mangroves or cordgrass or beach grass might grow. Microscopic algae and plants provide important habitats for life, sometimes acting as hiding and foraging places for larval forms of larger fish and invertebrates.

Algal life is widespread and very diverse under the ocean. Microscopic photosynthetic algae contribute a larger proportion of the world's photosynthetic output than all the terrestrial forests combined. Most of the niche occupied by sub plants on land is actually occupied by macroscopic algae in the ocean, such as Sargassum and kelp, which are commonly known as seaweeds that creates kelp forests.

Microscopic algae and plants provide important habitats for life, sometimes acting as hiding and foraging places for larval forms of larger fish and invertebrates.

Plants and algae

Over 1500 species of fungi are known from marine environments.[16] These parasitize marine algae or animals, or are saprobes on algae, corals, protozoan cysts, sea grasses, wood and other substrata, and can also be found in sea foam.[17] Spores of many species have special appendages which facilitate attachment to the substratum.[18] A very diverse range of unusual secondary metabolites is produced by marine fungi.[19]

Fungi

Reptiles which inhabit or frequent the sea include sea turtles, sea snakes, terrapins, the marine iguana, and the saltwater crocodile. Most extant marine reptiles, except for some sea snakes, are oviparous and need to return to land to lay their eggs. Thus most species, excepting sea turtles, spend most of their lives on or near land rather than in the ocean. Despite their marine adaptations, most sea snakes prefer shallow waters nearby land, around islands, especially waters that are somewhat sheltered, as well as near estuaries.[14][15] Some extinct marine reptiles, such as ichthyosaurs, evolved to be viviparous and had no requirement to return to land.

Reptiles

There are five main types of marine mammals.

Mammals

As on land, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes Cnidaria such as jellyfish and sea anemones; Ctenophora; sea worms including the phyla Platyhelminthes, Nemertea, Annelida, Sipuncula, Echiura, Chaetognatha, and Phoronida; Mollusca including shellfish, squid, octopus; Arthropoda including Chelicerata and Crustacea; Porifera; Bryozoa; Echinodermata including starfish; and Urochordata including sea squirts or tunicates.

Invertebrates

A reported 32,700 species of fish have been described (as of December 2013),[12] more than the combined total of all other vertebrates. About 60% of fish species are saltwater fish.[13]

Fish anatomy includes a two-chambered heart, operculum, swim bladder, scales, fins, lips, eyes and secretory cells that produce mucous. Fish breathe by extracting oxygen from water through their gills. Fins propel and stabilize the fish in the water. Many fish fall under two major categories - Elasmobranchii and Teleostei.

Fish

Birds adapted to living in the marine environment are often referred to as seabirds. Examples include albatross, penguins, gannets, and auks. Although they spend most of their lives in the ocean, species such as gulls can often be found thousands of miles inland.

Birds

Animals

Marine biology is a branch of biology and is closely linked to oceanography. It also encompasses many ideas from ecology. Fisheries science and marine conservation can be considered partial offshoots of marine biology (as well as environmental studies). Marine Chemistry, Physical oceanography and Atmospheric sciences are closely related to this field.

Related fields

Recent marine biotechnology has focused largely on marine biomolecules, especially proteins, that may have uses in medicine or engineering. Marine environments are the home to many exotic biological materials that may inspire biomimetic materials.

Other subfields study the physical effects of continual immersion in sea water and the ocean in general, adaptation to a salty environment, and the effects of changing various oceanic properties on marine life. A subfield of marine biology studies the relationships between oceans and ocean life, and global warming and environmental issues (such as carbon dioxide displacement).

The marine ecosystem is large, and thus there are many sub-fields of marine biology. Most involve studying specializations of particular animal groups, such as phycology, invertebrate zoology and ichthyology.

Coral reefs form complex marine ecosystems with tremendous biodiversity.

Subfields

The creation of marine laboratories was important because it allowed marine biologists to conduct research and process their specimens from expeditions. The oldest marine laboratory in the world, Station biologique de Roscoff, was established in France in 1872. In the United States, the Scripps Institution of Oceanography dates back to 1903, while the prominent Woods Hole Oceanographic Institute was founded in 1930.[10] The development of technology such as sound navigation ranging, scuba diving gear, submersibles and remotely operated vehicles allowed marine biologists to discover and explore life in deep oceans that was once thought to not exist.[11]

The observations made in the first studies of marine biology fuelled the age of discovery and exploration that followed. During this time, a vast amount of knowledge was gained about the life that exists in the oceans of the world. Many voyages contributed significantly to this pool of knowledge. Among the most significant were the voyages of the HMS Beagle where Charles Darwin came up with his theories of evolution and on the formation of coral reefs.[8] Another important expedition was undertaken by HMS Challenger, where findings were made of unexpectedly high species diversity among fauna stimulating much theorizing by population ecologists on how such varieties of life could be maintained in what was thought to be such a hostile environment.[9] This era was important for the history of marine biology but naturalists were still limited in their studies because they lacked technology that would allow them to adequately examine species that lived in deep parts of the oceans.

Early instances of the study of marine biology trace back to Aristotle (384–322 BC) who made several contributions which laid the foundation for many future discoveries and were the first big step in the early exploration period of the ocean and marine life.[6] The British naturalist Edward Forbes (1815–1854) is regarded by some as the founder of the science of marine biology.[7] The pace of oceanographic and marine biology studies quickly accelerated during the course of the 19th century.

HMS Challenger during its pioneer expedition of 1872–76

History

Contents

  • History 1
  • Subfields 2
    • Related fields 2.1
  • Animals 3
    • Birds 3.1
    • Fish 3.2
    • Invertebrates 3.3
    • Mammals 3.4
    • Reptiles 3.5
  • Fungi 4
  • Plants and algae 5
  • Microscopic life 6
  • Marine habitats 7
    • Intertidal and shore 7.1
    • Reefs 7.2
    • Open ocean 7.3
    • Deep sea and trenches 7.4
  • Distribution factors 8
  • See also 9
  • Lists 10
  • References 11
  • Further references 12
  • External links 13

Many species are economically important to humans, including carbon cycle) and of air (such as Earth's respiration, and movement of energy through ecosystems including the ocean). Large areas beneath the ocean surface still remain effectively unexplored.

[5]

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