Editing Indian Ocean (section)

==Marine life==
{{Multiple image
| total_width       = 600
| image1            = CSIRO ScienceImage 3012 Dolphin.jpg
| image2            = Maldives Surgeonfish, Acanthurus leucosternon.jpg
| image3            = Vagues et manchots à l'assaut de la plage.jpg
| footer            = A dolphin off Western Australia and a swarm of [[Acanthurus leucosternon|surgeonfish]] near Maldives Islands represents the well-known, exotic fauna of the warmer parts of the Indian Ocean. King Penguins on a beach in the [[Crozet Islands|Crozet Archipelago]] near Antarctica attract fewer tourists.
}}

Among the tropical oceans, the western Indian Ocean hosts one of the largest concentrations of [[phytoplankton]] blooms in summer, due to the strong [[monsoon]] winds. The monsoonal wind forcing leads to a strong coastal and open ocean [[upwelling]], which introduces nutrients into the upper zones where sufficient light is available for [[photosynthesis]] and phytoplankton production. These phytoplankton blooms support the marine ecosystem, as the base of the marine food web, and eventually the larger fish species. The Indian Ocean accounts for the second-largest share of the most economically valuable [[tuna]] catch.<ref>{{Harvnb|FAO 2016}}</ref> Its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, [[South Korea]], and [[Taiwan]] also exploit the Indian Ocean, mainly for [[shrimp]] and tuna.<ref name="CIAWFB-2018" />

Research indicates that increasing ocean temperatures are taking a toll on the marine ecosystem. A study on the phytoplankton changes in the Indian Ocean indicates a decline of up to 20% in the marine plankton in the Indian Ocean, during the past six decades. The tuna catch rates have also declined 50–90% during the past half-century, mostly due to increased industrial fisheries, with the [[ocean warming]] adding further stress to the fish species.<ref>{{Harvnb|Roxy|2016|loc=Discussion, pp. 831–832}}</ref>

Endangered and vulnerable marine mammals and turtles:<ref>{{Cite web|title=IUCN Red List|publisher=[[IUCN]]|url=https://www.iucnredlist.org/search?redListCategory=en|access-date=8 July 2019|archive-date=8 July 2019|archive-url=https://web.archive.org/web/20190708032948/https://www.iucnredlist.org/search?redListCategory=en|url-status=live}}.  Search parametres: Mammalia/Testudines, EN/VU, Indian Ocean Antarctic/Eastern/Western</ref>

{| class="wikitable"
|-
 ! Name || Distribution || Trend
|-
 ! colspan="3" | Endangered
|-
 | [[Australian sea lion]]<br />(''Neophoca cinerea'') || Southwest Australia || Decreasing
|-
 | [[Blue whale]]<br />(''Balaenoptera musculus'') || Global || Increasing
|-
 | [[Sei whale]]<br />(''Balaenoptera borealis'') || Global || Increasing
|-
 | [[Irrawaddy dolphin]]<br />(''Orcaella brevirostris'') || Southeast Asia || Decreasing
|-
 | [[Indian Ocean humpback dolphin]]<br />(''Sousa plumbea'') || Western Indian Ocean || Decreasing
|-
 | [[Green sea turtle]]<br />(''Chelonia mydas'') || Global || Decreasing
|-
 ! colspan="3" | Vulnerable
|-
 | [[Dugong]]<br />(''Dugong dugon'') || Equatorial Indian Ocean and Pacific || Decreasing
|-
 | [[Sperm whale]]<br />(''Physeter macrocephalus'') || Global || Unknown
|-
 | [[Fin whale]]<br />(''Balaenoptera physalus'') || Global || Increasing
|-
 | [[Australian snubfin dolphin]]<br />(''Orcaella heinsohni'') || Northern Australia, New Guinea || Decreasing
|-
 | [[Indo-Pacific humpback dolphin]]<br />(''Sousa chinensis'') || Southeast Asia || Decreasing
|-
 | [[Indo-Pacific finless porpoise]]<br />(''Neophocaena phocaenoides'') || Northern Indian Ocean, Southeast Asia || Decreasing
|-
 | [[Australian humpback dolphin]]<br />(''Sousa sahulensis'') || Northern Australia, New Guinea || Decreasing
|-
 | [[Leatherback]]<br />(''Dermochelys coriacea'') || Global || Decreasing
|-
 | [[Olive ridley sea turtle]]<br />(''Lepidochelys olivacea'') || Global || Decreasing
|-
 | [[Loggerhead sea turtle]]<br />(''Caretta caretta'') || Global || Decreasing
|}

80% of the Indian Ocean is open ocean and includes nine [[large marine ecosystem]]s: the [[Agulhas Current]], [[Somali Coastal Current]], [[Red Sea]], [[Arabian Sea]], [[Bay of Bengal]], [[Gulf of Thailand]], [[West Central Australian Shelf]], [[Northwest Australian Shelf]] and [[Southwest Australian Shelf]]. Coral reefs cover c. {{Convert|200000|km2|abbr=on}}. The coasts of the Indian Ocean includes beaches and intertidal zones covering {{Convert|3000|km2|abbr=on}} and 246 larger [[Estuary|estuaries]]. [[Upwelling]] areas are small but important. The hypersaline [[saltern]]s in India covers between {{Convert|5000|-|10000|km2|abbr=on}} and species adapted for this environment, such as ''[[Artemia salina]]'' and ''[[Dunaliella salina]]'', are important to bird life.<ref>{{Harvnb|Wafar|Venkataraman|Ingole|Khan|2011|loc=Marine ecosystems of the IO}}</ref>

{{Multiple image | total_width = 400
 | image1 = Padadita Beach, Waingapu 18.jpg
 | image2 = Coelacanth1.JPG
 | footer = Left: Mangroves (here in East Nusa Tenggara, Indonesia) are the only tropical to subtropical forests adapted for a coastal environment.  From their origin on the coasts of the Indo-Malaysian region, they have reached a global distribution.<br />Right: The coelacanth (here a model from Oxford), thought extinct for millions of years, was rediscovered in the 20th century.  The Indian Ocean species is blue whereas the Indonesian species is brown.
}}
Coral reefs, sea grass beds, and mangrove forests are the most productive ecosystems of the Indian Ocean&nbsp;— coastal areas produce 20 tones of fish per square kilometre. These areas, however, are also being urbanised with populations often exceeding several thousand people per square kilometre and fishing techniques become more effective and often destructive beyond sustainable levels while the increase in [[sea surface temperature]] spreads coral bleaching.<ref>{{Harvnb|Souter|Lindén|2005|loc=Foreword, pp. 5–6}}</ref>

[[Mangrove]]s covers {{Convert|80984|km2|abbr=on}} in the Indian Ocean region, or almost half of the world's mangrove habitat, of which {{Convert|42500|km2|abbr=on}} is located in Indonesia, or 50% of mangroves in the Indian Ocean. Mangroves originated in the Indian Ocean region and have adapted to a wide range of its habitats but it is also where it suffers its biggest loss of habitat.<ref>{{Harvnb|Kathiresan|Rajendran|2005|loc=Introduction; Mangrove habitat, pp. 104–105}}</ref>

In 2016, six new animal species were identified at [[hydrothermal vents]] in the Southwest Indian Ridge: a "Hoff" crab, a "giant peltospirid" snail, a whelk-like snail, a limpet, a scaleworm and a polychaete worm.<ref>{{cite news|title=New marine life found in deep sea vents|date=15 December 2016|publisher=BBC News|url=https://www.bbc.co.uk/news/science-environment-38305989|access-date=15 December 2016|archive-date=15 December 2016|archive-url=https://web.archive.org/web/20161215042627/http://www.bbc.co.uk/news/science-environment-38305989|url-status=live}}</ref>

The [[West Indian Ocean coelacanth]] was discovered in the Indian Ocean off South Africa in the 1930s and in the late 1990s another species, the [[Indonesian coelacanth]], was discovered off [[Sulawesi Island]], Indonesia. Most extant coelacanths have been found in the Comoros. Although both species represent an order of [[Sarcopterygii|lobe-finned fishes]] known from the Early Devonian (410 {{Abbr|mya|million years ago}}) and thought extinct 66 mya, they are morphologically distinct from their Devonian ancestors. Over millions of years, coelacanths evolved to inhabit different environments&nbsp;— lungs adapted for shallow, brackish waters evolved into gills adapted for deep marine waters.<ref>{{Harvnb|Cupello|Clément|Meunier|Herbin|2019|loc=Introduction, p. 29}}</ref>