Editing Zooplankton (section)

===Microzooplankton===
Microzooplankton are defined as heterotrophic and [[Mixotrophic dinoflagellate|mixotrophic]] plankton. They primarily consist of [[phagotrophic]] [[protist]]s, including ciliates, dinoflagellates, and [[mesozooplankton]] [[Nauplius (larva)|nauplii]].<ref>{{cite journal |doi = 10.4319/lo.1978.23.6.1256|title = Pelagic ecosystem structure: Heterotrophic compartments of the plankton and their relationship to plankton size fractions 1|year = 1978|author1-link=John McNeill Sieburth|last1 = Sieburth|first1 = John McN.|last2 = Smetacek|first2 = Victor|last3 = Lenz|first3 = Jürgen|journal = Limnology and Oceanography|volume = 23|issue = 6|pages = 1256–1263|bibcode = 1978LimOc..23.1256S| s2cid=85568208 |doi-access = free}}</ref> Microzooplankton are major [[Zooplankton grazing|grazers]] of the plankton community. As the primary consumers of marine phytoplankton, microzooplankton consume ~ 59–75% daily of the [[marine primary production]], much larger than mesozooplankton. That said, macrozooplankton can sometimes have greater consumption rates in eutrophic ecosystems because the larger phytoplankton can be dominant there.<ref>{{cite journal |doi = 10.4319/lo.2004.49.1.0051|title = Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems|year = 2004|last1 = Calbet|first1 = Albert|last2 = Landry|first2 = Michael R.|journal = Limnology and Oceanography|volume = 49|issue = 1|pages = 51–57|bibcode = 2004LimOc..49...51C|hdl = 10261/134985|s2cid = 22995996|hdl-access = free}}</ref><ref name="Calbet2008">{{cite journal |doi = 10.1093/icesjms/fsn013|title = The trophic roles of microzooplankton in marine systems|year = 2008|last1 = Calbet|first1 = Albert|journal = ICES Journal of Marine Science|volume = 65|issue = 3|pages = 325–331|doi-access = free}}</ref> Microzooplankton are also pivotal regenerators of nutrients which fuel primary production and food sources for metazoans.<ref name="Calbet2008" /><ref name="Liu2020">{{cite journal |last1=Liu |first1=Kailin |last2=Chen |first2=Bingzhang |last3=Zheng |first3=Liping |last4=Su |first4=Suhong |last5=Huang |first5=Bangqin |last6=Chen |first6=Mianrun |last7=Liu |first7=Hongbin |year=2021 |title=What controls microzooplankton biomass and herbivory rate across marginal seas of China?|journal=Limnology and Oceanography |volume=66 |issue=1 |pages=61–75 |bibcode=2021LimOc..66...61L |doi=10.1002/lno.11588 |issn=0024-3590 |s2cid=224916151 |doi-access=free}} [[File:CC-BY_icon.svg|50x50px]] Material was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]].</ref>

Despite their ecological importance, microzooplankton remain understudied. Routine oceanographic observations seldom monitor microzooplankton biomass or herbivory rate, although the dilution technique, an elegant method of measuring microzooplankton herbivory rate, has been developed for over four decades (Landry and Hassett 1982). The number of observations of microzooplankton herbivory rate is around 1600 globally,<ref>{{cite journal |doi = 10.4319/lo.2012.57.2.0519|title = Does warming enhance the effect of microzooplankton grazing on marine phytoplankton in the ocean?|year = 2012|last1 = Chen|first1 = Bingzhang|last2 = Landry|first2 = Michael R.|last3 = Huang|first3 = Bangqin|last4 = Liu|first4 = Hongbin|journal = Limnology and Oceanography|volume = 57|issue = 2|pages = 519–526|bibcode = 2012LimOc..57..519C|doi-access = }}</ref><ref>{{cite journal |doi = 10.1093/plankt/fbt023|title = Microzooplankton grazing in the oceans: Impacts, data variability, knowledge gaps and future directions|year = 2013|last1 = Schmoker|first1 = Claire|last2 = Hernández-León|first2 = Santiago|last3 = Calbet|first3 = Albert|journal = Journal of Plankton Research|volume = 35|issue = 4|pages = 691–706|doi-access = free}}</ref> far less than that of primary productivity (> 50,000).<ref>{{cite journal |doi = 10.1002/gbc.20074|title = Combined constraints on global ocean primary production using observations and models|year = 2013|last1 = Buitenhuis|first1 = Erik T.|last2 = Hashioka|first2 = Taketo|last3 = Quéré|first3 = Corinne Le|journal = Global Biogeochemical Cycles|volume = 27|issue = 3|pages = 847–858|bibcode = 2013GBioC..27..847B|s2cid = 140628035|doi-access = free}}</ref> This makes validating and optimizing the grazing function of microzooplankton difficult in ocean ecosystem models.<ref name="Liu2020" />