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 {{reflist|2}}
 [[Category:Marine biology| ]]
 [[Category:Biological oceanography]]
 [[Category:Fisheries]]

wikademia>Eme at 16:39, 22 December 2009

2009-12-22T16:39:20Z

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	~~{{Refimprove\|date=March 2009}}~~
	[[Image:World ocean map.gif‎\|thumb\|right\|World Marine Environment.]]		[[Image:World ocean map.gif‎\|thumb\|right\|World Marine Environment.]]
	'''Marine biology''' is the scientific study of living [[organism]]s in the [[ocean]] or other [[Marine (ocean)\|marine]] or [[brackish]] bodies of water. Given that in [[biology]] many [[scientific classification\|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 (biophysical)\|environment]] rather than on [[taxonomy]]. Marine biology differs from [[marine ecology]] as marine [[ecology]] is focused on how organisms interact with each other and environment and [[biology]] is the study of the animal itself.		'''Marine biology''' is the scientific study of living [[organism]]s in the [[ocean]] or other [[Marine (ocean)\|marine]] or [[brackish]] bodies of water. Given that in [[biology]] many [[scientific classification\|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 (biophysical)\|environment]] rather than on [[taxonomy]]. Marine biology differs from [[marine ecology]] as marine [[ecology]] is focused on how organisms interact with each other and environment and [[biology]] is the study of the animal itself.

wikademia>Wikademia: http://en.wikipedia.org/w/index.php?title=Marine_biology&action=edit

2009-10-24T20:50:30Z

http://en.wikipedia.org/w/index.php?title=Marine_biology&action=edit

New page

{{Refimprove|date=March 2009}}
[[Image:World ocean map.gif‎|thumb|right|World Marine Environment.]]
'''Marine biology''' is the scientific study of living [[organism]]s in the [[ocean]] or other [[Marine (ocean)|marine]] or [[brackish]] bodies of water. Given that in [[biology]] many [[scientific classification|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 (biophysical)|environment]] rather than on [[taxonomy]]. Marine biology differs from [[marine ecology]] as marine [[ecology]] is focused on how organisms interact with each other and environment and [[biology]] is the study of the animal itself.

Marine life is a vast resource, providing [[food]], [[medicine]], and raw materials, in addition to helping to support [[recreation]] and [[tourism]] all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the [[oxygen]] cycle, and are involved in the regulation of the Earth's [[climate]]. <ref name = DMS>{{cite journal
| tournal = Climatic Change
| title = Planktonic dimethylsulfide and cloud albedo: An estimate of the feedback response
| volume = 18
| issue= 1
| coauthors = Karl E. Taylor, Steven J. Ghan
| doi = 10.1007/BF00142502
| url = http://www.springerlink.com/content/hm3h1q666x206h46
| journal = Climatic Change
}}</ref> [[Shoreline]]s are in part shaped and protected by marine life, and some marine organisms even help create new land.<ref name=Sousa>{{cite book
| last = Sousa
| first = Wayne P
| others = eds. Steward T. A. Pickett & P. S. White
| title = The Ecology of Natural Disturbance and Patch Dynamics
| origyear = 1985
| publisher = Academic Press
| isbn = 0125545215
| chapter = 7, Disturbance and Patch Dynamics on Rocky Intertidal Shores
| chapterurl = http://books.google.co.uk/books?hl=en&lr=&id=jIj-qAflWxQC&oi=fnd&pg=PA101&dq=patch+dynamics+shoreline&ots=A3N1dTGrzY&sig=pYTEgphmnY3leFv_KU-_yAYSOy8
| year = 1986
}}</ref>

Marine biology covers a great deal, from the microscopic, including most [[zooplankton]] and [[phytoplankton]] to the huge [[cetaceans]] (whales) which reach up to a reported 48 [[meters]] (125 [[foot (length)|feet]]) in length.

The habitats studied by marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in [[surface tension]] between the ocean and atmosphere, to the depths of the [[Ocean trench|abyssal trenches]], sometimes 10,000 meters or more beneath the surface of the ocean. It studies habitats such as [[coral reef]]s, [[kelp forest]]s, [[tidepools]], muddy, sandy and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary.

A large amount of all [[life on Earth]] exists in the oceans. Exactly how large the proportion is still unknown. A lot of species living in oceans are still to be discovered. While the oceans comprise about 71% of the Earth's surface, due to their depth they encompass about 300 times the habitable volume of the terrestrial habitats on Earth.

Many species are economically important to humans, including [[fishery|food fish]]. It is also becoming understood that the well-being of marine organisms and other organisms are linked in very fundamental ways. The human body of knowledge regarding the relationship between life in the sea and important cycles is rapidly growing, with new discoveries being made nearly every day. These cycles include those of matter (such as the [[carbon cycle]]) and of air (such as [[Global climate model|Earth's respiration]], and movement of energy through [[ecosystem]]s including the ocean). Large areas beneath the ocean surface still remain effectively unexplored.

== Subfields ==
The [[marine ecosystem]] is large, and thus there are many subfields of marine biology. Most involve studying specializations of particular animal groups. (i.e. [[phycology]], [[invertebrate zoology]] and [[ichthyology]]).

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).

Recent marine [[biotechnology]] has focused largely on [[marine biomolecule]]s, especially [[protein]]s, that may have uses in medicine or engineering. Marine environments are the home to many exotic biological materials that may inspire [[Bionics|biomimetic material]]s.

=== Related fields ===
Marine biology is a branch of [[oceanography]] and is closely linked to [[biology]]. 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.

== Lifeforms ==
=== Microscopic life ===
[[Image:Copepodkils.jpg|thumb|right|A [[copepod]].]]
Microscopic life undersea is incredibly diverse and still poorly understood. For example, the role of [[virus]]es in marine ecosystems is barely being explored even in the beginning of the 21st century.

The role of [[phytoplankton]] is better understood due to their critical position as the most numerous [[primary production|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), [[diatom]]s, [[dinoflagellate]]s, [[Euglenid|euglenoids]], [[coccolithophorid]]s, [[cryptomonad]]s, [[chrysophyte]]s, [[chlorophyte]]s, [[prasinophyte]]s, and [[silicoflagellate]]s.

[[Zooplankton]] tend to be somewhat larger, and not all are microscopic. Many [[Protozoa]] are zooplankton, including dinoflagellates, [[zooflagellate]]s, [[foraminifera]]ns, and [[radiolarian]]s. Some of these (such as dinoflaggelates) are also phytoplankton; the [[plant/animal distinction]] often breaks down in very small organisms. Other zooplankton include [[cnidarian]]s, [[ctenophore]]s, [[chaetognatha|chaetognaths]], [[mollusc]]s, [[arthropod]]s, [[Tunicate|urochordates]], and [[annelid]]s such as [[polychaete]]s. Many larger animals begin their life as zooplankton before they become large enough to take their familiar forms. Two examples are fish [[larva]]e and sea stars (also called [[starfish]]).

=== Plants and algae ===
Plant life is widespread and very diverse under the sea. Microscopic photosynthetic algae contribute a larger proportion of the worlds photosynthetic output than all the terrestrial forests combined. Most of the [[ecological niche|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 [[seaweed]]s that create [[kelp forest]]s. The non algae plants that survive in the sea are often found in shallow waters, such as the [[seagrass]]es (examples of which are eelgrass, ''[[Zostera]]'', and turtle grass, ''Thalassia''). These plants have adapted to the high salinity of the ocean environment. The [[foreshore|intertidal zone]] is also a good place to find plant life in the sea, where [[mangroves]] or [[cordgrass]] or [[Ammophila (Poaceae)|beach grass]] might grow. Macroscopic algae and plants provide important habitats for life, sometimes acting as hiding and foraging places for larval forms of larger fish and invertebrates.

[[Image:Crown of Thorns-jonhanson.jpg|thumb|right|A [[crown-of-thorns starfish]].'']]

===Marine invertebrates ===
{{Main|Marine invertebrates}}
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 anemone]]s; [[Ctenophora]]; [[sea worm]]s including the [[phylum (biology)|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 squirt]]s or [[tunicate]]s.

=== Fish ===
{{main | Fish}}
Fish have [[evolution|evolved]] very different biological functions from other large organisms. Fish anatomy includes a two-chambered heart, [[Operculum (Fish)|operculum]], secretory [[cell (biology)|cells]] that produce [[mucous]], [[swim bladder]], [[scale (zoology)|scales]], [[fin]]s, [[lip]]s and [[eye]]s. Fish breathe by extracting oxygen from water through their gills. Fins propel and stabilize the fish in the water.

Well known fish include: [[sardine]]s, [[anchovy]], [[ling cod]], [[clownfish]] (also known as anemonefish), and [[Bottom feeder|bottom fish]] which include [[halibut]] or [[ling cod]]. [[Predator]]s include [[shark]]s and [[barracuda]].

[[Image:Chelonia mydas and bubbles.jpg|thumb|right|[[Green turtle]].]]

=== Reptiles ===
{{main|Marine reptile}}
[[Reptile]]s which inhabit or frequent the sea include [[sea turtle]]s, [[sea snake]]s, [[terrapin]]s, the [[marine iguana]], and the [[saltwater crocodile]]. Most [[extant taxon|extant]] marine reptiles, except for some sea snakes, are [[oviparity|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 not far from land, around islands, especially waters that are somewhat sheltered, as well as near estuaries.<ref name="Sti74">Stidworthy J. 1974. Snakes of the World. Grosset & Dunlap Inc. 160 pp. ISBN 0-448-11856-4.</ref><ref name="RAS-FAO">[ftp://ftp.fao.org/docrep/fao/009/y0870e/y0870e65.pdf Sea snakes] at [http://www.fao.org/ Food and Agriculture Organization of the United Nations]. Accessed [[7 August]] [[2007]].</ref> Some [[extinction|extinct]] marine reptiles, such as [[ichthyosaur]]s, evolved to be [[viviparity|viviparous]] and had no requirement to return to land.

=== Seabirds ===
{{main|Seabird}}
[[Seabird]]s are species of [[bird]]s adapted to living in the marine environment, examples including [[albatross]], [[penguin]]s, [[gannet]]s, and [[auk]]s. Although they spend most of their lives in the ocean, species such as [[gull]]s can often be found thousands of miles inland.

[[Image:Sea otters holding hands.jpg|thumb|right|[[Sea otter]]s.]]

=== Marine mammals ===
{{main | Marine mammal}}
There are five main types of marine mammals.
* [[Cetacea]]ns include [[toothed whale]]s (Suborder [[Odontoceti]]), such as the [[Sperm Whale]], [[dolphin]]s, and [[porpoise]]s such as the [[Dall's porpoise]]. Cetaceans also include [[baleen whale]]s (Suborder [[Mysticeti]]), such as the [[Gray Whale]], [[Humpback Whale]], and [[Blue Whale]].
* [[Sirenian]]s include [[manatee]]s, the [[Dugong]], and the extinct [[Steller's Sea Cow]].
* [[Pinniped|Seal]]s (Family [[Phocidae]]), [[sea lion]]s (Family [[Otariidae]] - which also include the fur seals), and the [[Walrus]] (Family [[Odobenidae]]) are all considered [[pinniped]]s.
* The [[Sea Otter]] is a member of the Family [[Mustelidae]], which includes [[weasel]]s and [[badger]]s.
* The [[Polar Bear]] (Family [[Ursidae]]) is sometimes considered a marine mammal because of its dependence on the sea.

==Oceanic habitats==
{{ocean habitat topics}}
=== Reefs ===
{{main | Coral reef}}
[[Image:Coral reefs in papua new guinea.JPG|thumb|200px|left|[[Coral]]s and reef fish in [[Papua New Guinea]].]]
[[Reef]]s comprise some of the densest and most diverse habitats in the world. The best-known types of reefs are [[tropical]] [[coral reef]]s which exist in most tropical waters; however, reefs can also exist in cold water. Reefs are built up by [[coral]]s 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 reef]]s. Coral reefs also support a huge community of life, including the corals themselves, their symbiotic [[zooxanthellae]], tropical fish and many other organisms.

Much attention in marine biology is focused on coral reefs and the [[El Niño]] weather phenomenon. In 1998, coral reefs experienced a "once in a thousand years" bleaching event, in which vast expanses of reefs across the Earth died because sea surface temperatures rose well above normal. Some reefs are recovering, but scientists say that 58[[%]] of the world's coral reefs are now endangered and predict that [[global warming]] could exacerbate this trend.

=== Deep sea and trenches ===
The deepest recorded [[oceanic trench]]es measure to date is the [[Mariana Trench]], near the [[Philippines]], in the [[Pacific Ocean]] at 10924 m (35838 ft). At such depths, [[water pressure]] is extreme and there is no sunlight, but some life still exists. Small flounder (family [[Soleidae]]) fish and shrimp were seen by the American crew of the [[bathyscaphe]] ''[[Bathyscaphe Trieste|Trieste]]'' when it dove to the bottom in 1960.

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 8605 m (28232 ft), the [[Romanche Trench]] at 7760 m (24450 ft), [[Fram Basin]] in the [[Arctic Ocean]] at 4665 m (15305 ft), the [[Java Trench]] at 7450 m (24442 ft), and the [[South Sandwich Trench]] at 7235 m (23737 ft).

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.

Much life centers on [[seamount]]s that rise from the depths, where fish and other sea life congregate to spawn and feed. [[Hydrothermal vent]]s along the [[mid-ocean ridge]] spreading centers act as [[oasis|oases]], as do their opposites, [[cold seeps]]. Such places support unique [[biome]]s and many new [[microbe]]s and other lifeforms have been discovered at these locations.

===Open ocean===
{{main | Pelagic zone}}
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]]. The open ocean consists mostly of [[Jellyfish]] and its predators such as the [[Mola mola]].

===Intertidal and shore===
[[Image:Tide pools in santa cruz.jpg|200px|thumb|Tide pools with sea stars and [[sea anemone]] in Santa Cruz,[[California]]]][[Intertidal zone]]s, 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.

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]].

==Distribution factors==
An active research topic in marine biology is to discover and map the [[biological life cycle|life cycle]]s of various species and where they spend their time. Marine biologists study how the [[ocean current]]s, [[tide]]s and many other oceanic factors affect ocean lifeforms, including their growth, distribution and well-being. This has only recently become technically feasible with advances in [[Global Positioning System|GPS]] and newer underwater visual devices.

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 turtle]]s and some [[shark]]s 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.

== See also ==
{{portalbox
|name1=Environment
|image1=Devils Punchbowl Waterfall, New Zealand.jpg
|name2=Ecology
|image2=Earth flag PD.jpg
|name3=Earth sciences
|image3=Terra.png
|name4=Water
|image4=Drinking water.jpg}}
{{Div col|cols=2}}
* [[World Ocean Atlas]]
* [[Oceanic climate]]
* [[Aquaculture]]
* [[Freshwater biology]]
* [[Phycology]]
* [[Oceanic Basin]]
* [[Modular Ocean Model]]
* [[Bathymetry]]
* [[Acoustic ecology]]
* [[Sea Life Centres|A Chain of themed Sea Life Centres]]
{{Div col end}}
{{br}}

== Lists ==
{{Div col|cols=2}}
* [[Index of biology articles]]
* [[List of marine biologists]]
* [[Large marine ecosystem]]
* [[Glossary of ecology]]
* [[List of ecologists]]
* [[List of important publications in biology#Ecology]]
* [[Outline of biology]]
* [[Outline of ecology]]
{{Div col end}}

== References ==
{{reflist|2}}

== External links ==
{{Commonscat}}
{{WVD}}
{{Wikibooks}}
{{wiktionary}}
*{{dmoz|Science/Biology/Ecology/Aquatic_Ecology/Marine}}

{{Biology-footer}}
{{aquatic ecosystem topics}}
{{Natural sciences-footer}}
{{fishery science topics|state=collapsed}}
{{Physical Earth}}
{{Nature nav}}

{{DEFAULTSORT:Marine Biology}}
[[Category:Marine biology| ]]
[[Category:Biological oceanography]]
[[Category:Fisheries]]

About marine biology - Revision history

wikademia>Eme: /* External links */

wikademia>Eme at 16:39, 22 December 2009

wikademia>Wikademia: http://en.wikipedia.org/w/index.php?title=Marine_biology&action=edit