Editing Plankton (section)

== Trophic groups ==
{{plankton sidebar|trophic}}

Plankton are primarily divided into broad functional (or [[trophic level]]) groups:   
*'''[[Phytoplankton]]''' (from Greek ''phyton'', or plant) are [[autotroph]]ic [[prokaryote|prokaryotic]] or [[eukaryote|eukaryotic]] [[algae]] that live near the water surface where there is sufficient [[light]] to support [[photosynthesis]]. Among the more important groups are the [[diatom]]s, [[cyanobacteria]], [[dinoflagellate]]s, and [[coccolithophore]]s.
*'''[[Zooplankton]]''' (from Greek ''zoon'', or animal) are small [[protozoa]]ns or [[metazoa]]ns (e.g. [[crustacean]]s and other [[animal]]s) that feed on other plankton. Some of the [[egg]]s and [[larva]]e of larger nektonic animals, such as fish, crustaceans, and [[annelid]]s, are included here.
*'''[[Mycoplankton]]''' include [[fungi]] and [[Fungus#Fungus-like organisms|fungus-like organisms]], which, like bacterioplankton, are also significant in [[remineralisation]] and [[nutrient cycling]].<ref>{{cite book |last1=Wang |first1=G. |last2= Wang, X. |last3= Liu |first3=X. |last4=Li |first4= Q. |editor-last=Raghukumar |editor-first=Chandralata |date=2012 |chapter=Diversity and biogeochemical function of planktonic fungi in the ocean |title=Biology of Marine Fungi |url=https://books.google.com/books?id=1kE5OpuGp9YC |publisher=Springer Berlin Heidelberg |pages=71–88 |isbn=978-3-642-23342-5}}</ref>
*'''[[Bacterioplankton]]''' include [[bacteria]] and [[archaea]], which play an important role in remineralising organic material down the water column (note that prokaryotic phytoplankton are also bacterioplankton).
*'''[[Virioplankton]]''' are [[Marine virus|viruses]]. Viruses are more abundant in the plankton than bacteria and archaea, though much smaller.<ref>{{cite journal |last1=Wommack |first1=K.E. |last2=Colwell |first2=R.R. |date=March 2000 |title=Virioplankton: viruses in aquatic ecosystems |journal=Microbiology and Molecular Biology Reviews |volume=64 |issue=1 |pages=69–114 |doi=10.1128/MMBR.64.1.69-114.2000 |pmid=10704475 |pmc=98987 }}</ref><ref>{{cite web |title=Plankton |url=https://education.nationalgeographic.org/resource/plankton/ |website=Resource Library |publisher=[[National Geographic]] |access-date=13 September 2019}}</ref>

=== Mixoplankton ===
{{further|Marine microorganisms#Mixotrophs|Mixotrophic dinoflagellate}}

*'''[[Mixotroph]]s'''. Plankton have traditionally been categorized as [[Autotroph|producer]], [[Heterotroph|consumer]], and recycler groups, but some plankton are able to benefit from more than just one trophic level. In this mixed trophic strategy—known as mixotrophy—organisms act as both producers and consumers, either at the same time or switching between modes of nutrition in response to ambient conditions. This makes it possible to use photosynthesis for growth when nutrients and light are abundant, but switch to eating phytoplankton, zooplankton or each other when growing conditions are poor. Mixotrophs are divided into two groups; constitutive mixotrophs (CMs) which are able to perform photosynthesis on their own, and non-constitutive mixotrophs (NCMs) which use [[phagocytosis]] to engulf phototrophic prey that are either kept alive inside the host cell, which benefits from its photosynthesis, or they digested, except for the [[plastid]]s, which continue to perform photosynthesis ([[kleptoplasty]]).<ref>{{cite journal| url = https://academic.oup.com/plankt/article/40/6/627/5165357| title = Modelling mixotrophic functional diversity and implications for ecosystem function - Oxford Journals| journal = Journal of Plankton Research| date = November 2018| volume = 40| issue = 6| pages = 627–642| doi = 10.1093/plankt/fby044| last1 = Leles| first1 = Suzana Gonçalves}}</ref>
Recognition of the importance of mixotrophy as an ecological strategy is increasing,<ref>{{cite journal |last1=Hartmann |first1=M. |last2=Grob |first2=C. |last3=Tarran |first3=G.A. |last4=Martin |first4=A.P. |last5=Burkill |first5=P.H. |last6=Scanlan |first6=D.J. |last7=Zubkov |first7=M.V. |date=2012 |title=Mixotrophic basis of Atlantic oligotrophic ecosystems |journal=Proc. Natl. Acad. Sci. USA |volume=109 |issue=15 |pages=5756–5760 |doi=10.1073/pnas.1118179109 |pmid=22451938 |pmc=3326507 |bibcode=2012PNAS..109.5756H |doi-access=free }}</ref> as well as the wider role this may play in marine [[biogeochemistry]].<ref>{{cite journal |last1=Ward |first1=B.A. |last2=Follows |first2=M.J. |date=2016 |title=Marine mixotrophy increases trophic transfer efficiency, mean organism size, and vertical carbon flux |journal=Proc. Natl. Acad. Sci. USA |volume=113 |issue=11 |pages=2958–2963 |doi=10.1073/pnas.1517118113 |pmid=26831076 |pmc=4801304 |bibcode=2016PNAS..113.2958W |doi-access=free }}</ref> Studies have shown that mixotrophs are much more important for marine ecology than previously assumed and comprise more than half of all microscopic plankton.<ref>{{cite magazine| url = https://www.the-scientist.com/news-opinion/mixing-it-up-in-the-web-of-life-65431| title = Mixing It Up in the Web of Life| magazine = The Scientist Magazine| access-date = <!-- unknown, too far back -->| archive-date = 2021-01-21| archive-url = https://web.archive.org/web/20210121092951/https://www.the-scientist.com/news-opinion/mixing-it-up-in-the-web-of-life-65431| url-status = dead}}</ref><ref>{{cite web| url = https://theconversation.com/uncovered-the-mysterious-killer-triffids-that-dominate-life-in-our-oceans-67387| title = Uncovered: the mysterious killer triffids that dominate life in our oceans| date = 3 November 2016}}</ref> Their presence acts as a buffer that prevents the collapse of ecosystems during times with little to no light.<ref>{{Cite web |url=https://www.astrobio.net/news-exclusive/catastrophic-darkness/ |title=Catastrophic Darkness |work=Astrobiology Magazine |access-date=2019-11-27 |archive-url=https://web.archive.org/web/20150926012623/http://www.astrobio.net/news-exclusive/catastrophic-darkness/ |archive-date=2015-09-26 |url-status=dead }}</ref>