Editing Marine biology

{{Short description|Scientific study of organisms that live in the ocean}}
{{for|the scientific journal|Marine Biology (journal)}}
{{redirect|Marine biologist|the Seinfeld episode|The Marine Biologist}}
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| footer = Marine biology studies species ([[marine life]]) that live in [[marine habitat]]s ([[coastal]] and [[open ocean]] habitats). Clockwise from top left: [[Tide pool]] in [[Santa Cruz, California|Santa Cruz]], United States; School of [[barracuda]] at [[Pom Pom Island]], Malaysia; [[Fan mussel]] in a [[Mediterranean Sea|Mediterranean]] [[seagrass meadow]]; Research [[submarine]] for marine research.
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{{TopicTOC-Biology}}
'''Marine biology''' is the scientific study of the [[biology]] of [[marine life]], organisms that inhabit the [[sea]]. Given that in [[biology]] many [[scientific classification|phyla]], [[family (biology)|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 (biology)|taxonomy]].

A large proportion of all [[life|life on Earth]] lives in the ocean. The exact size of this "large proportion" is unknown, since many ocean species are still to be discovered. The ocean is a complex three-dimensional world,<ref>[http://www.marine-conservation.org/media/shining_sea/theme_oceanography.htm Oceanographic and Bathymetric Features] {{Webarchive|url=https://web.archive.org/web/20130925165000/http://www.marine-conservation.org/media/shining_sea/theme_oceanography.htm |date=2013-09-25 }} ''Marine Conservation Institute''. Uploaded 18 September 2013.</ref> covering approximately 71% of the Earth's surface. The habitats studied in 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 [[oceanic trench]]es, sometimes 10,000 meters or more beneath the surface of the ocean. 

Specific habitats include [[estuaries]], [[coral reef]]s, [[kelp forest]]s, [[seagrass meadows]], the surrounds of [[seamount]]s and [[thermal vent]]s, [[tidepool]]s, 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. The organisms studied range from microscopic [[phytoplankton]] and [[zooplankton]] to huge [[cetaceans]] (whales) {{convert|25-32|m|ft|abbr=off|sp=us}} in length. [[Marine ecosystem|Marine ecology]] is the study of how marine organisms interact with each other and the environment.

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 | title=Planktonic dimethylsulfide and cloud albedo: An estimate of the feedback response| last1=Foley| first1=Jonathan A.| last2=Taylor| first2=Karl E.| last3=Ghan| first3=Steven J.| doi=10.1007/BF00142502| journal=Climatic Change| volume=18| issue=1| year=1991| pages=1| bibcode=1991ClCh...18....1F| s2cid=154990993}}</ref> [[Shore]]lines 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.| editor1-last=Pickett| editor1-first=Steward T. A.| editor2-last=White| editor2-first=P. S.| title=The Ecology of Natural Disturbance and Patch Dynamics| orig-year=1985| publisher=Academic Press| isbn=978-0-12-554521-1| chapter=7, Disturbance and Patch Dynamics on Rocky Intertidal Shores| chapter-url=https://books.google.com/books?id=jIj-qAflWxQC&q=patch+dynamics+shoreline&pg=PA101| year=1986| url-access=registration| url=https://archive.org/details/ecologyofnatural0000pick}}</ref>

Many species are economically important to humans, including both finfish and shellfish. It is also becoming understood that the well-being of marine organisms and other organisms are linked in 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.

== Biological oceanography ==
{{main|Biological oceanography}}
[[File:BlueMarble-2001-2002.jpg|thumb|400px|right|Marine biology studies species that live in [[marine habitat]]s. 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 [[Coastline paradox|360,000 kilometres]].<ref>{{cite journal |last=Charette |first=Matthew |author2=Smith, Walter H. F. |title=The volume of Earth's ocean |journal=Oceanography |year=2010 |volume=23 |issue=2 |pages=112–114 |doi=10.5670/oceanog.2010.51 |doi-access=free |hdl=1912/3862 |hdl-access=free }}</ref><ref>[https://www.cia.gov/the-world-factbook/countries/world/ World] ''The World Factbook'', CIA. Retrieved 13 January 2014.</ref>|alt=Two views of the ocean from space]]
Marine biology can be contrasted with [[biological oceanography]]. [[Marine life]] is a field of study both in marine biology and in biological [[oceanography]]. Biological oceanography is the study of how organisms affect and are affected by the [[physics]], [[chemistry]], and [[geology]] of the [[ocean|oceanographic system]]. Biological oceanography mostly focuses on the [[microorganism]]s within the ocean; looking at how they are affected by their environment and how that affects larger marine creatures and their ecosystem.<ref name="Lalli Parsons">Lalli, Carol M., and Timothy R. Parsons. "Introduction." Biological Oceanography: An Introduction. First Edition ed. Tarrytown, New York: Pergamon, 1993. 7–21. Print.</ref> 

Biological oceanography is similar to marine biology, but it studies ocean life from a different perspective. Biological oceanography takes a bottom up approach in terms of the food web, while marine biology studies the ocean from a top down perspective. Biological oceanography mainly focuses on the ecosystem of the ocean with an emphasis on [[plankton]]: their diversity (morphology, nutritional sources, motility, and metabolism); their productivity and how that plays a role in the global carbon cycle; and their distribution (predation and life cycle).<ref name="Lalli Parsons" /><ref>{{cite web|last=Menden-Deuer|first=Susanne|author-link1=Susanne Menden-Deuer|title=Course Info, OCG 561 Biological Oceanography|url=http://www.gso.uri.edu/ocg561/|access-date=2021-03-19|archive-date=2018-01-29|archive-url=https://web.archive.org/web/20180129094359/http://www.gso.uri.edu/ocg561/|url-status=dead}}</ref><ref>{{cite book|last=Miller|first=Charles B.|title=Biological Oceanography|author2=Patricia A. Wheeler|publisher=John Wiley & Sons|year=2012|edition=Second|location=Chinchester, West Sussex}}</ref> Biological oceanography also investigates the role of microbes in food webs, and how humans impact the [[ecosystem]]s in the oceans.<ref name="Lalli Parsons" /><ref name=Mills1995>{{cite journal |doi = 10.1007/BF02368334|title = From marine ecology to biological oceanography|year = 1995|last1 = Mills|first1 = Eric L.|journal = Helgoländer Meeresuntersuchungen|volume = 49|issue = 1–4|pages = 29–44|bibcode = 1995HM.....49...29M|url = https://rdcu.be/chiJn|s2cid = 22149101|doi-access = free}}</ref>

==Marine habitats==
[[File:Callyspongia sp. (Tube sponge).jpg|thumb|[[Coral reef]]s provide marine habitats for tube sponges, which in turn become marine habitats for fish]]
{{Ocean habitat topics}}
{{main|Marine habitats}}

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. Alternatively, marine habitats can be divided into [[pelagic]] and [[demersal]] habitats. Pelagic habitats are found near the surface or in the open [[water column]], away from the bottom of the ocean and affected by [[ocean current]]s, while demersal habitats are near or on the bottom. Marine habitats can be modified by their inhabitants. Some marine organisms, like corals, kelp and sea grasses, are [[ecosystem engineer]]s which reshape the marine environment to the point where they create further habitat for other organisms.

===Intertidal and near shore===
[[File:Tide pools in santa cruz.jpg|thumb|left|Tide pools with [[sea stars]] and [[sea anemone]]]]

[[Intertidal zone]]s, the areas that are close to the shore, are constantly being exposed and covered by the ocean's [[tides]]. A huge array of life can be found 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]].{{clear left}}

===Estuaries===
[[File:Urdaibai, Bizkaia, Euskal Herria.jpg|thumb|left|Estuaries have shifting flows of sea water and fresh water.]]

[[Estuaries]] are also near shore and influenced by the [[tides]]. An estuary is a partially enclosed coastal body of water with one or more rivers or streams flowing into it and with a free connection to the open sea.<ref name="james">{{cite book |last=Pritchard |first=D. W. |year=1967 |chapter= What is an estuary: physical viewpoint |pages=3–5 |editor-first=G. H. |editor-last=Lauf |title= Estuaries |series=A.A.A.S. Publ. |volume=83 |location=Washington, DC }}</ref> Estuaries form a transition zone between freshwater river environments and saltwater maritime environments. They are subject both to marine influences—such as tides, waves, and the influx of saline water—and to riverine influences—such as flows of fresh water and sediment. The shifting flows of both sea water and fresh water provide high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.<ref name="McLusky">{{cite book |last1=McLusky |first1=D. S. |last2=Elliott |first2=M. |year=2004 |title=The Estuarine Ecosystem: Ecology, Threats and Management |location=New York |publisher=Oxford University Press |isbn=978-0-19-852508-0 }}</ref>{{clear left}}

=== Reefs ===
[[File:Maldivesfish2.jpg|thumb|left|[[Coral reef]]s form complex marine ecosystems with tremendous [[biodiversity]].]]
{{Main|Coral reef}}

[[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 the most severe mass bleaching events on record, when vast expanses of reefs across the world died because [[sea surface temperature]]s rose well above normal.<ref>NOAA (1998) Record-breaking coral bleaching occurred in tropics this year. [[National Oceanic and Atmospheric Administration]], Press release (October 23, 1998).</ref><ref>ICRS (1998) Statement on Global Coral Bleaching in 1997-1998. International Coral Reef Society, October 15, 1998.</ref> 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.<ref>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.</ref><ref>{{cite journal | last1=Goreau | first1=T. J. | year=1992 | title=Bleaching and Reef Community Change in Jamaica: 1951 - 1991 | journal=Am. Zool. | volume=32 | issue=6| pages=683–695 | doi=10.1093/icb/32.6.683| doi-access=free }}</ref><ref>{{cite journal | last1=Sebens | first1=K. P. | year=1994 | title=Biodiversity of Coral Reefs: What are We Losing and Why? | journal=Am. Zool. | volume=34 | pages=115–133 | doi=10.1093/icb/34.1.115| doi-access=free }}</ref><ref>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.</ref>{{clear left}}

[[File:Representative ocean animal life.jpg|thumb|upright=1.7| Some representative ocean animal life (not drawn to scale) within their approximate depth-defined ecological habitats. [[Marine microorganisms]] exist on the surfaces and within the tissues and organs of the diverse life inhabiting the ocean, across all ocean habitats.<ref name="Apprill2017">Apprill, A. (2017)"Marine animal microbiomes: toward understanding host–microbiome interactions in a changing ocean". ''Frontiers in Marine Science'', '''4''': 222. {{doi|10.3389/fmars.2017.00222}}. [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>]]

===Open ocean===
[[File:Humpback stellwagen edit.jpg|thumb|left|The open ocean is the area of deep sea beyond the [[continental shelves]].]]
{{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. The open ocean is separated into different zones, and the different zones each have different ecologies.<ref>{{Cite web|url=http://marinebio.org/oceans/open-ocean/|title=The Open Ocean - MarineBio.org|website=marinebio.org|access-date=2016-09-26}}</ref> Zones which vary according to their depth include the [[epipelagic]], [[mesopelagic]], [[bathypelagic]], [[abyssopelagic]], and [[hadopelagic]] zones. Zones which vary by the amount of light they receive include the [[Photic zone|photic]] and [[aphotic zone]]s. Much of the aphotic zone's energy is supplied by the open ocean in the form of [[detritus]].{{clear left}}

=== Deep sea and trenches ===
[[File:Deep sea chimaera.jpg|thumb|left| A deep-sea [[chimaera]]. Its snout is covered with [[Ampullae of Lorenzini|tiny pores]] capable of detecting animals by perturbations in electric fields.]]

The deepest recorded [[oceanic trench]] measured to date is the [[Mariana Trench]], near the [[Philippines]], in the [[Pacific Ocean]] at {{convert|10,924|m|ft|abbr=on}}. 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 crew of the [[bathyscaphe]] ''[[Bathyscaphe Trieste|Trieste]]'' when it dove to the bottom in 1960, which led to scientific debate surrounding the likelihood of bony fish surviving in such deep waters. General scientific consensus has discredited the possible viewing of a flatfish at such depths.<ref>{{Cite journal |last=Yancey |first=Paul H. |last2=Gerringer |first2=Mackenzie E. |last3=Drazen |first3=Jeffrey C. |last4=Rowden |first4=Ashley A. |last5=Jamieson |first5=Alan |date=2014-03-25 |title=Marine fish may be biochemically constrained from inhabiting the deepest ocean depths |url=https://pnas.org/doi/full/10.1073/pnas.1322003111 |journal=Proceedings of the National Academy of Sciences |language=en |volume=111 |issue=12 |pages=4461–4465 |doi=10.1073/pnas.1322003111 |issn=0027-8424|pmc=3970477 }}</ref><ref name=":0">Polmar, Norman; Mathers, Lee J. (January 2020). "The First Deepest Dive". ''U.S. Naval Institute Proceedings''. 146/1/1, 403.</ref><ref name=":1">{{Cite journal |last=Jamieson |first=Alan J. |last2=Yancey |first2=Paul H. |date=June 2012 |title=On the Validity of the Trieste Flatfish: Dispelling the Myth |url=https://www.journals.uchicago.edu/doi/10.1086/BBLv222n3p171 |journal=The Biological Bulletin |language=en |volume=222 |issue=3 |pages=171–175 |doi=10.1086/BBLv222n3p171 |issn=0006-3185 |via=University of Chicago Press Journals}}</ref><ref name=":2">[http://bjsonline.com/watches/articles/0022_3.shtml Seven Miles Down: The Story of The Bathyscaph Trieste.] {{webarchive|url=https://web.archive.org/web/20070202144233/http://bjsonline.com/watches/articles/0022_3.shtml |date=2007-02-02 }}, ''Rolex Deep Sea Special'', January 2006.</ref> 

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.<ref>{{Cite web|url=https://www.encyclopedia.com/earth-and-environment/geology-and-oceanography/geology-and-oceanography/aphotic-zone|title=Aphotic Zone {{!}} Encyclopedia.com|website=www.encyclopedia.com|access-date=2018-12-06|archive-date=2023-07-10|archive-url=https://web.archive.org/web/20230710092355/https://www.encyclopedia.com/earth-and-environment/geology-and-oceanography/geology-and-oceanography/aphotic-zone|url-status=live}}</ref> Many life forms that live at these depths have the ability to create their own light known as [[bio-luminescence]]. Marine life also flourishes around [[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. There is still much more to learn about the deeper parts of the [[ocean]].<ref>{{Cite book|url=https://books.google.com/books?id=nAAtDwAAQBAJ&q=%22Deep-Sea+Fishes%22|title=Deep-Sea Fishes: Biology, Diversity, Ecology and Fisheries|isbn=9781107083820|last1=Priede|first1=Imants G.|pages = 12–13 |date=10 August 2017|publisher=Cambridge University Press }}</ref>

{{clear}}

== Marine life ==
{{main article|Marine life}}
{{marine life sidebar}}

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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 their environment rather than their taxonomy. For this reason, marine biology encompasses not only organisms that live only in a marine environment, but also other organisms whose lives revolve around the sea.

=== Microscopic life ===
{{main article|Marine microorganism}}

As inhabitants of the largest environment on Earth, microbial marine systems drive changes in every global system. Microbes are responsible for virtually all [[photosynthesis]] that occurs in the ocean, as well as the cycling of [[carbon]], [[nitrogen]], [[phosphorus]] and other [[nutrients]] and trace elements.<ref>{{cite web |url=https://www.sciencedaily.com/releases/2015/12/151210181647.htm |title=Functions of global ocean microbiome key to understanding environmental changes |date=December 10, 2015 |website=www.sciencedaily.com |publisher=University of Georgia |access-date=December 11, 2015 |archive-date=December 14, 2015 |archive-url=https://web.archive.org/web/20151214175012/http://www.sciencedaily.com/releases/2015/12/151210181647.htm |url-status=live }}</ref>

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.<ref>{{cite journal|last=Suttle
|first=C.A.|title=Viruses in the Sea|journal=Nature|year=2005|volume=437|issue=9|pages=356–361|doi=10.1038/nature04160|pmid=16163346|bibcode=2005Natur.437..356S|s2cid=4370363}}</ref>

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 dinoflagellates) are also phytoplankton; the distinction between plants and animals often breaks down in very small organisms. Other zooplankton include [[cnidarian]]s, [[Ctenophora (phylum)|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 ===
{{main article|Marine algae and plants}}

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

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 (plant)|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.

===Invertebrates===
{{Main|Marine invertebrates}}

As on land, [[invertebrates]], or animals that lack a backbone, make up a huge portion of all life in the sea. Invertebrate sea life includes [[Cnidaria]] such as [[jellyfish]] and [[sea anemone]]s; [[Ctenophora (phylum)|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.

=== Fungi ===
{{main|Marine fungi}}

Over 10,000<ref>{{Cite journal|last1=Amend|first1=Anthony|last2=Burgaud|first2=Gaetan|last3=Cunliffe|first3=Michael|last4=Edgcomb|first4=Virginia P.|last5=Ettinger|first5=Cassandra L.|last6=Gutiérrez|first6=M. H.|last7=Heitman|first7=Joseph|last8=Hom|first8=Erik F. Y.|last9=Ianiri|first9=Giuseppe|last10=Jones|first10=Adam C.|last11=Kagami|first11=Maiko|date=2019-03-05|title=Fungi in the Marine Environment: Open Questions and Unsolved Problems|journal=mBio|volume=10|issue=2|language=EN|doi=10.1128/mBio.01189-18|pmid=30837337|pmc=6401481|s2cid=73481006}}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> species of [[fungi]] are known from marine environments.<ref>{{cite journal|last=Hyde|first=K.D. |author2=E.B.J. Jones |author3=E. Leaño |author4=S.B. Pointing |author5=A.D. Poonyth |author6=L.L.P. Vrijmoed|title=Role of fungi in marine ecosystems|journal=Biodiversity and Conservation|year=1998|volume=7|issue=9|pages=1147–1161|doi=10.1023/A:1008823515157|bibcode=1998BiCon...7.1147H |s2cid=22264931 }}</ref> These are parasitic on [[marine algae]] or animals, or are [[saprobe]]s on algae, corals, protozoan cysts, sea grasses, wood and other substrata, and can also be found in [[sea foam]].<ref>Kirk, P.M., Cannon, P.F., Minter, D.W. and Stalpers, J. "Dictionary of the Fungi". Edn 10. CABI, 2008</ref> Spores of many species have special appendages which facilitate attachment to the substratum.<ref>{{cite journal|last=Hyde|first=K.D.|author2=E.B.J. Jones|title=Spore attachment in marine fungi|journal=Botanica Marina|year=1989|volume=32|issue=3|pages=205–218|doi=10.1515/botm.1989.32.3.205|s2cid=84879817}}</ref> A very diverse range of unusual secondary [[metabolite]]s is produced by marine fungi.<ref>{{cite journal|last=San-Martín|first=A. |author2=S. Orejanera |author3=C. Gallardo |author4=M. Silva |author5=J. Becerra |author6=R. Reinoso |author7=M.C. Chamy |author8=K. Vergara |author9=J. Rovirosa|title=Steroids from the marine fungus Geotrichum sp|journal=Journal of the Chilean Chemical Society|year=2008|volume=53|issue=1|pages=1377–1378|doi=10.4067/S0717-97072008000100011 |doi-access=free }}</ref>

===Vertebrates===
{{main article|Marine vertebrates}}

==== Fish ====
{{main article|Fish}}

A reported [[Diversity of fish|33,400 species of fish]], including [[bony fish|bony]] and [[cartilaginous fish]], had been described by 2016,<ref>{{cite web |url=http://www.fishbase.org/ |title=Fishbase |access-date=6 February 2017 |archive-date=17 October 2017 |archive-url=https://web.archive.org/web/20171017132213/http://www.fishbase.org/ |url-status=live }}</ref> more than all other vertebrates combined. About 60% of fish species live in saltwater.<ref>{{cite book |author=Moyle, P. B.; Leidy, R. A. |date=1992 |title=Loss of biodiversity in aquatic ecosystems: Evidence from fish faunas |pages=128–169 |editor=Fiedler, P. L.; Jain, S. A. Jain |work=Conservation Biology: the theory and practice of nature conservation, preservation, and management |publisher=Chapman and Hall}}</ref>

==== 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, excluding 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.<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]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }} at [http://www.fao.org/ Food and Agriculture Organization of the United Nations] {{Webarchive|url=https://web.archive.org/web/20120711004347/http://www.fao.org/ |date=2012-07-11 }}. 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.

==== Birds ====
{{Main|Seabird}}

Birds adapted to living in the [[marine environment]] are often called [[seabird]]s. Examples include [[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.

==== Mammals ====
{{Main|Marine mammal}}

There are five main types of marine mammals: [[cetacea]]ns ([[toothed whale]]s and [[baleen whale]]s); [[sirenian]]s such as [[manatee]]s; [[pinniped]]s including seals and the [[walrus]]; [[sea otter]]s; and the 
[[polar bear]]. All are air-breathing, meaning that while some such as the [[sperm whale]] can dive for prolonged periods, all must return to the surface to breathe.<ref>{{Cite journal | doi=10.1371/journal.pone.0019653| pmid=21625431| title=Current and Future Patterns of Global Marine Mammal Biodiversity| journal=PLOS ONE| volume=6| issue=5| pages=e19653| year=2011| last1=Kaschner | first1=K. | last2=Tittensor | first2=D. P. | last3=Ready | first3=J. | last4=Gerrodette | first4=T. | last5=Worm | first5=B. | bibcode=2011PLoSO...619653K| pmc=3100303| doi-access=free}}</ref><ref>{{Cite journal | last1=Pompa | first1=S. | last2=Ehrlich | first2=P. R. | last3=Ceballos | first3=G. | doi=10.1073/pnas.1101525108 | pmid=21808012 | title=Global distribution and conservation of marine mammals | journal=Proceedings of the National Academy of Sciences| volume=108 | issue=33 | pages=13600–13605| date=2011-08-16 | bibcode=2011PNAS..10813600P | pmc=3158205 | doi-access=free }}</ref>

{{clear}}

== Subfields ==
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]]. 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.

Through constant monitoring of the ocean, there have been discoveries of marine life which could be used to create remedies for certain diseases such as cancer and leukemia. In addition, Ziconotide, an approved drug used to treat pain, was created from a snail which resides in the ocean.<ref>{{cite journal |last1=Malve |first1=Harshad |title=Exploring the ocean for new drug developments: Marine pharmacology |journal=Journal of Pharmacy & Bioallied Sciences |date=2016 |volume=8 |issue=2 |pages=83–91 |doi=10.4103/0975-7406.171700 |pmid=27134458 |pmc=4832911 |doi-access=free }}</ref>

=== Related fields ===
Marine biology is a branch of [[biology]]. It is closely linked to [[oceanography]], especially [[biological oceanography]], and may be regarded as a sub-field of [[marine science]]. 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 science]]s are also closely related to this field.

==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. Technologies that aid in this discovery include [[pop-up satellite archival tag]]s, [[acoustic tag]]s, and a variety of other [[data loggers]]. Marine biologists study how the [[ocean current]]s, [[tide]]s 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 [[Global Positioning System|GPS]] and newer underwater visual devices.<ref>{{Cite journal |last1=Hulbert |first1=Ian A.R. |last2=French |first2=John |date=21 December 2001 |title=The accuracy of GPS for wildlife telemetry and habitat mapping: GPS for telemetry and mapping |journal=Journal of Applied Ecology |language=en |volume=38 |issue=4 |pages=869–878 |doi=10.1046/j.1365-2664.2001.00624.x|doi-access=free }}</ref>

Most ocean life breeds in specific places, nests 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 especially in the infant and juvenile years. For example, it is still largely unknown where juvenile [[sea turtle]]s and some [[shark]]s in the first year of their life travel. Recent advances in underwater tracking devices are illuminating what we know about marine organisms that live at great ocean depths.<ref>{{Cite web | url=http://us7.campaign-archive2.com/?u=82eb97f4b587306a3537ecf16&id=e398851e6b&e=%5BUNIQID%5D | title=March 2014 Newsletter - What's Going on at Desert Star}}</ref> The information that [[pop-up satellite archival tag]]s gives aids in fishing closures for certain times of the year and the development of [[marine protected area]]s. This data is important to both 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.

== History ==
{{main|History of marine biology}}
[[File:Scyliorhinus retifer embryo.JPG|thumb|left|[[Aristotle's biology|Aristotle]] recorded that the [[embryo]] of [[Mustelus canis|<!--a different species shown-->a dogfish]] was attached by a cord to a kind of placenta (the [[yolk sac]]).<ref>{{cite book|author=Leroi, Armand Marie|title=The Lagoon: How Aristotle Invented Science|title-link=Aristotle's Lagoon|date=2014|publisher=Bloomsbury|isbn=978-1-4088-3622-4|pages=72–74|author-link=Armand Marie Leroi}}</ref>]]

The study of marine biology dates to [[Aristotle]] (384–322 BC), who made [[Aristotle's biology#Empirical research|many observations of life in the sea]] around [[Lesbos]], laying the foundation for many future discoveries.<ref>"History of the Study of Marine Biology - MarineBio.org". MarineBio Conservation Society. Web. Monday, March 31, 2014. <http://marinebio.org/oceans/history-of-marine-biology.asp {{Webarchive|url=https://wayback.archive-it.org/all/20140303174702/http://www.marinebio.org/oceans/history-of-marine-biology.asp|date=2014-03-03}}></ref> In 1768, [[Samuel Gottlieb Gmelin]] (1744–1774) published the ''Historia Fucorum'', the first work dedicated to marine [[algae]] and the first book on marine biology to use the new [[binomial nomenclature]] of [[Carl Linnaeus|Linnaeus]]. It included elaborate illustrations of seaweed and marine algae on folded leaves.<ref>Gmelin S G (1768) [https://books.google.com/books?id=YUAAAAAAQAAJ&q=%22Historia+Fucorum%22 ''Historia Fucorum''] Ex typographia Academiae scientiarum, St. Petersburg.</ref><ref>Silva PC, Basson PW and Moe RL (1996) [https://books.google.com/books?id=vuWEemVY8WEC&dq=%22Historia+Fucorum%22+binomial+nomenclature&pg=PA2 ''Catalogue of the Benthic Marine Algae of the Indian Ocean''] {{Webarchive|url=https://web.archive.org/web/20230405201157/https://books.google.com/books?id=vuWEemVY8WEC&dq=%22Historia+Fucorum%22+binomial+nomenclature&pg=PA2 |date=2023-04-05 }} page 2, University of California Press. {{ISBN|9780520915817}}.</ref> The British naturalist [[Edward Forbes]] (1815–1854) is generally regarded as the founder of the science of marine biology.<ref>{{cite web|title=A Brief History of Marine Biology and Oceanography|url=http://www.meer.org/ebook/mbhist.htm|access-date=31 March 2014|archive-date=3 August 2020|archive-url=https://web.archive.org/web/20200803202907/http://www.meer.org/ebook/mbhist.htm|url-status=dead}}</ref> The pace of oceanographic and marine biology studies quickly accelerated during the course of the 19th century.

[[File:Challenger.jpg|thumb|right|{{center|{{HMS|Challenger|1858|6}} during its [[Challenger expedition|pioneer expedition]] of 1872–1876}}]]

The observations made in the first studies of marine biology fueled 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 {{HMS|Beagle}} where [[Charles Darwin]] came up with his theories of [[evolution]] and on the formation of [[coral reefs]].<ref>Ward, Ritchie R. Into the ocean world; the biology of the sea. 1st ed. New York: Knopf; [distributed by Random House], 1974: 161</ref> Another important expedition was undertaken by [[HMS Challenger (1858)|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.<ref>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</ref> 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.

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 Concarneau, France founded by the College of France in 1859.<ref>{{Cite web|date=2018-06-17|title=A History Of The Study Of Marine Biology ~ MarineBio Conservation Society|url=https://www.marinebio.org/creatures/marine-biology/history-of-marine-biology/|access-date=2022-02-17|language=en-US}}</ref> In the United States, the [[Scripps Institution of Oceanography]] dates back to 1903, while the prominent [[Woods Hole Oceanographic Institute]] was founded in 1930.<ref>Maienschein, Jane. 100 years exploring life, 1888-1988: the Marine Biological Laboratory at Woods Hole. Boston: Jones and Bartlett Publishers, 1989: 189-192</ref> The development of technology such as [[Sonar|sound navigation and ranging]], [[scuba diving]] gear, [[submersible]]s and [[Remotely operated underwater vehicle|remotely operated vehicles]] allowed marine biologists to discover and explore life in deep oceans that was once thought to not exist.<ref>{{cite web|last=Anderson|first=Genny|title=Beginnings: History of Marine Science|url=http://marinebio.net/marinescience/01intro/behist.htm|access-date=2014-04-08|archive-date=2012-12-20|archive-url=https://web.archive.org/web/20121220034255/http://www.marinebio.net/marinescience/01intro/behist.htm|url-status=live}}</ref> Public interest in the subject continued to develop in the post-war years with the publication of [[Rachel Carson]]'s sea trilogy (1941–1955).

In 1960, the [[bathyscaphe]] [[Trieste (bathyscaphe)|Trieste]] descended the furthest point man had yet traveled, bottoming [[Challenger Deep|Challenger's Deep]] at 35,797 feet.<ref name=":0" /> The vessel was captained by [[Jacques Piccard]] and [[Don Walsh]], whose discoveries while at the bottom of the ocean bolstered scientific discussion and interest about life in the hadal zone.<ref name=":0" /><ref name=":1" /><ref name=":2" />
{{Further|Sonic characteristics of marine species}}

== See also ==
{{Portal|Environment|Ecology|Earth sciences|Marine life|Oceans|Water|Underwater diving}}
{{Div col|colwidth=30em}}
* [[Acoustic ecology]]
* [[Aquaculture]]
* [[Bathymetry]]
* [[Biological oceanography]]
* [[Effects of climate change on oceans]]
* [[Freshwater biology]]
* [[Types of concrete#Marine habitat concrete|Marine habitat concrete]]
* [[Modular ocean model]]
* [[Oceanic basin]]
* [[Oceanic climate]]
* [[Phycology]]
{{div col end}}

=== Lists ===
{{Div col|colwidth=30em}}
* [[Glossary of ecology]]
* [[Index of biology articles]]
* [[Large marine ecosystem]]
* [[List of ecologists]]
* [[List of marine biologists]]
* [[List of marine ecoregions (WWF)]]
* [[Outline of biology]]
* [[Outline of ecology]]
{{div col end}}

== References ==
{{reflist|32em}}

== Further references ==
* Morrissey J and Sumich J (2011) [https://books.google.com/books?id=2cm_s-I01kcC&q=%22Introduction+to+the+Biology+of+Marine+Life%22 ''Introduction to the Biology of Marine Life''] {{Webarchive|url=https://web.archive.org/web/20201110191007/https://books.google.rs/books?id=2cm_s-I01kcC&printsec=frontcover&dq=%22Introduction+to+the+Biology+of+Marine+Life%22&hl=en&sa=X&ei=xGpWVMDQDuXUmgXO74KACA&redir_esc=y |date=2020-11-10 }} Jones & Bartlett Publishers. {{ISBN|9780763781606}}.
* Mladenov, Philip V., Marine Biology: A Very Short Introduction, 2nd edn (Oxford, 2020; online edn, Very Short Introductions online, Feb. 2020), http://dx.doi.org/10.1093/actrade/9780198841715.001.0001, accessed 21 Jun. 2020.

== External links ==
{{Commons category}}
* [http://ocean.si.edu/ Smithsonian Ocean Portal] {{Webarchive|url=https://web.archive.org/web/20100623005244/http://ocean.si.edu/ |date=2010-06-23 }}
* [http://www.mcsuk.org/ Marine Conservation Society] {{Webarchive|url=https://web.archive.org/web/20080731214736/http://www.mcsuk.org/ |date=2008-07-31 }}
* [https://archive.today/20130111125741/http://www.wileyonlinelibrary.com/journal/maec Marine Ecology – an evolutionary perspective]
* [http://onlinelibrary.wiley.com/doi/10.1111/mae.2011.32.issue-s1/issuetoc Free special issue: Marine Biology in Time and Space] {{Webarchive|url=https://web.archive.org/web/20170630032806/http://onlinelibrary.wiley.com/doi/10.1111/mae.2011.32.issue-s1/issuetoc |date=2017-06-30 }}
* [https://www.youtube.com/watch?v=iGRJjuMLMgE Creatures of the deep ocean] {{Webarchive|url=https://web.archive.org/web/20131112235447/http://www.youtube.com/watch?v=iGRJjuMLMgE |date=2013-11-12 }} – ''National Geographic'' documentary, 2010.
* [http://www.exploris.org.uk Exploris] {{Webarchive|url=https://web.archive.org/web/20060207100344/http://www.exploris.org.uk/ |date=2006-02-07 }}
* [http://content.lib.washington.edu/fishweb/index.html Freshwater and Marine Image Bank] {{Webarchive|url=https://web.archive.org/web/20131008011909/http://content.lib.washington.edu/fishweb/index.html |date=2013-10-08 }} – From the University of Washington Library
* [http://www.marinetraining.eu Marine Training Portal] {{Webarchive|url=https://web.archive.org/web/20160630085826/http://www.marinetraining.eu/ |date=2016-06-30 }} – Portal grouping training initiatives in the field of Marine Biology

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[[Category:Fisheries science]]
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