Editing Aquaculture (section)

==Ecological benefits==
{{see also|Nitrate vulnerable zone}}
While some forms of aquaculture can be devastating to ecosystems, such as shrimp farming in [[mangroves]], other forms can be beneficial. Shellfish aquaculture adds substantial [[filter feeding]] capacity to an environment which can significantly improve [[water quality]]. A single [[oyster]] can filter 15 gallons of water a day, removing microscopic algal cells. By removing these cells, shellfish are removing nitrogen and other nutrients from the system and either retaining it or releasing it as waste which sinks to the bottom. By harvesting these shellfish, the nitrogen they retained is completely removed from the system.<ref>{{cite journal|doi=10.2134/jeq2010.0203|pmid=21488516|title=Nutrient Bioassimilation Capacity of Aquacultured Oysters: Quantification of an Ecosystem Service|journal=Journal of Environmental Quality|volume=40|issue=1|pages=271–7|year=2011|last1=Higgins|first1=Colleen B.|last2=Stephenson|first2=Kurt|last3=Brown|first3=Bonnie L.|bibcode=2011JEnvQ..40..271H }}</ref> Raising and harvesting kelp and other macroalgae directly remove nutrients such as nitrogen and phosphorus. Repackaging these nutrients can relieve [[eutrophic]], or nutrient-rich, conditions known for their low [[Oxygen saturation|dissolved oxygen]] which can decimate [[species diversity]] and [[species abundance|abundance]] of marine life. Removing algal cells from the water also increases light penetration, allowing plants such as [[eelgrass]] to reestablish themselves and further increase oxygen levels.{{citation needed|date=October 2020}}<ref>{{cite journal |last1=Newell |first1=Roger |title=Top-down control of phytoplankton by oysters in Chesapeake Bay, USA |journal=Marine Ecology Progress Series |date=2007 |pages=293–298|doi=10.3354/meps341293 |doi-access=free}}</ref>

Aquaculture in an area can provide for crucial [[ecological function]]s for the inhabitants. Shellfish beds or cages can provide habitat structure. This structure can be used as shelter by invertebrates, small fish or [[crustacean]]s to potentially increase their abundance and maintain biodiversity. Increased shelter raises stocks of prey fish and small crustaceans by increasing recruitment opportunities in turn providing more prey for higher trophic levels. One study estimated that 10 square meters of [[oyster reef]] could enhance an ecosystem's [[biomass]] by 2.57&nbsp;kg<ref>{{cite journal|doi=10.3354/meps264249|title=Estimated enhancement of fish production resulting from restoring oyster reef habitat: quantitative valuation|journal=Marine Ecology Progress Series|volume=264|pages=249–264|year=2003|last1=Peterson|first1=CH|last2=Grabowski|first2=JH|last3=Powers|first3=SP|bibcode=2003MEPS..264..249P|doi-access=free}}</ref> [[Herbivore]] shellfish will also be preyed on. This moves energy directly from [[primary producer]]s to higher [[trophic level]]s potentially skipping out on multiple energetically costly trophic jumps which would increase biomass in the ecosystem.{{citation needed|date=October 2020}}

[[Seaweed farming]] is a [[carbon dioxide removal|carbon negative]] crop, with a high potential for [[climate change mitigation]].<ref>{{Cite journal|last1=Duarte|first1=Carlos M.|last2=Wu|first2=Jiaping|last3=Xiao|first3=Xi|last4=Bruhn|first4=Annette|last5=Krause-Jensen|first5=Dorte|date=2017|title=Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation?|journal=Frontiers in Marine Science|language=en|volume=4|page=100 |doi=10.3389/fmars.2017.00100|issn=2296-7745|doi-access=free|bibcode=2017FrMaS...4..100D |hdl=10754/623247|hdl-access=free}}</ref> The IPCC [[Special Report on the Ocean and Cryosphere in a Changing Climate]] recommends "further research attention" as a mitigation tactic.<ref>{{Cite book|last1=Bindoff|first1=N. L.|title=IPCC Special Report on the Ocean and Cryosphere in a Changing Climate|last2=Cheung|first2=W. W. L.|last3=Kairo|first3=J. G.|last4=Arístegui|first4=J.|last5=Guinder|first5=V. A.|last6=Hallberg|first6=R.|last7=Hilmi|first7=N. J. M.|last8=Jiao|first8=N.|last9=Karim|first9=Md S.|year=2019|pages=447–587|chapter=Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities|ref={{harvid|IPCC SROCC Ch5|2019}} <!-- ipcc:20200202 -->|display-authors=4|chapter-url=https://www.ipcc.ch/site/assets/uploads/sites/3/2019/11/09_SROCC_Ch05_FINAL.pdf|first10=L.|last16=Williamson|first16=P.|last15=Tagliabue|first15=A.|last14=Suga|last12=Purca Cuicapusa|last13=Rinkevich|first13=B.|first12=S. R.|last11=O'Donoghue|first11=S.|last10=Levin|first14=T.}}</ref> Regenerative ocean farming is a polyculture farming system that grows a mix of seaweeds and shellfish while sequestering carbon, decreasing nitrogen in the water and increasing oxygen, helping to regenerate and restore local habitat like reef ecosystems.<ref>{{Cite web|last=Carr|first=Gabriela|date=2021-03-15|title=Regenerative Ocean Farming: How Can Polycultures Help Our Coasts?|url=https://smea.uw.edu/currents/regenerative-ocean-farming-how-can-polycultures-help-our-coasts/|url-status=live|access-date=2021-10-29|website=School of Marine and Environmental Affairs|language=en-US|archive-url=https://web.archive.org/web/20210316015237/https://smea.uw.edu/currents/regenerative-ocean-farming-how-can-polycultures-help-our-coasts/ |archive-date=2021-03-16}}</ref>