Editing Phytoplankton (section)

== Aquaculture ==
{{see also|Algaculture|Culture of microalgae in hatcheries}}

Phytoplankton are a key food item in both [[aquaculture]] and [[mariculture]]. Both utilize phytoplankton as food for the animals being farmed. In mariculture, the phytoplankton is naturally occurring and is introduced into enclosures with the normal circulation of seawater. In aquaculture, phytoplankton must be obtained and introduced directly. The plankton can either be collected from a body of water or cultured, though the former method is seldom used. Phytoplankton is used as a foodstock for the production of [[rotifer]]s,<ref name=mcvey>McVey, James P., Nai-Hsien Chao, and Cheng-Sheng Lee. CRC Handbook of Mariculture Vol. 1 : Crustacean Aquaculture. New York: CRC Press LLC, 1993.{{page needed|date=February 2016}}</ref> which are in turn used to feed other organisms. Phytoplankton is also used to feed many varieties of aquacultured [[molluscs]], including [[pearl]] [[oyster]]s and [[giant clam]]s. A 2018 study estimated the nutritional value of natural phytoplankton in terms of carbohydrate, protein and lipid across the world ocean using ocean-colour data from satellites,<ref name=sroy>{{cite journal|last1=Roy|first1=Shovonlal|title=Distributions of phytoplankton carbohydrate, protein and lipid in the world oceans from satellite ocean colour|journal=The ISME Journal|volume=12|issue=6|pages=1457–1472|date=12 February 2018|doi=10.1038/s41396-018-0054-8|pmid=29434313|pmc=5955997|bibcode=2018ISMEJ..12.1457R |language=En|issn=1751-7370}}</ref> and found the calorific value of phytoplankton to vary considerably across different oceanic regions and between different time of the year.<ref name=sroy/><ref>{{cite news|title=Nutrition study reveals instability in world's most important fishing regions|url=https://phys.org/news/2018-02-nutrition-reveals-instability-world-important.html}}</ref>

The production of phytoplankton under artificial conditions is itself a form of aquaculture. Phytoplankton is cultured for a variety of purposes, including foodstock for other aquacultured organisms,<ref name=mcvey/> a nutritional supplement for captive [[invertebrate]]s in [[Aquarium|aquaria]]. Culture sizes range from small-scale [[laboratory]] cultures of less than 1L to several tens of thousands of litres for commercial aquaculture.<ref name=mcvey/> Regardless of the size of the culture, certain conditions must be provided for efficient growth of plankton. The majority of cultured plankton is marine, and [[seawater]] of a [[specific gravity]] of 1.010 to 1.026 may be used as a culture medium. This water must be [[Sterilization (microbiology)|sterilized]], usually by either high temperatures in an [[autoclave]] or by exposure to [[ultraviolet radiation]], to prevent [[biological]] [[contamination]] of the culture. Various [[fertilizer]]s are added to the culture medium to facilitate the growth of plankton. A culture must be aerated or agitated in some way to keep plankton suspended, as well as to provide dissolved [[carbon dioxide]] for [[photosynthesis]]. In addition to constant aeration, most cultures are manually mixed or stirred on a regular basis. Light must be provided for the growth of phytoplankton. The [[colour temperature]] of illumination should be approximately 6,500 K, but values from 4,000 K to upwards of 20,000 K have been used successfully. The duration of light exposure should be approximately 16 hours daily; this is the most efficient artificial day length.<ref name=mcvey/>
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