Editing Prochlorococcus (section)

==Distribution==
''Prochlorococcus'' is abundant in the [[Photic zone|euphotic]] zone of the world's tropical oceans.<ref>{{cite journal | last1 = Chisholm | first1 = S.W. | last2 = Frankel | first2 = S. | last3 = Goericke | first3 = R. | last4 = Olson | first4 = R. | last5 = Palenik | first5 = B. | last6 = Waterbury | first6 = J. | last7 = West-Johnsrud | first7 = L. | last8 = Zettler | first8 = E. | year = 1992 | title = ''Prochlorococcus marinus'' nov. gen. nov. sp.: an oxyphototrophic marine prokaryote containing divinyl chlorophyll a and b. | journal = Archives of Microbiology | volume = 157 | issue = 3| pages = 297–300 | doi=10.1007/bf00245165| bibcode = 1992ArMic.157..297C | s2cid = 32682912 }}</ref> It is possibly the most plentiful genus on Earth: a single millilitre of surface seawater may contain 100,000 cells or more. Worldwide, the average yearly abundance is {{val|2.8|to|3.0|e=27}} individuals<ref name=Flombaum13>{{Cite journal | last1 = Flombaum | first1 = P. | last2 = Gallegos | first2 = J. L. | last3 = Gordillo | first3 = R. A. | last4 = Rincon | first4 = J. | last5 = Zabala | first5 = L. L. | last6 = Jiao | first6 = N. | last7 = Karl | first7 = D. M. | last8 = Li | first8 = W. K. W. | last9 = Lomas | first9 = M. W. | doi = 10.1073/pnas.1307701110 | last10 = Veneziano | first10 = D. | last11 = Vera | first11 = C. S. | last12 = Vrugt | first12 = J. A. | last13 = Martiny | first13 = A. C. | title = Present and future global distributions of the marine Cyanobacteria ''Prochlorococcus'' and ''Synechococcus'' | journal = Proceedings of the National Academy of Sciences | volume = 110 | issue = 24 | pages = 9824–9 | year = 2013 | pmid =  23703908| pmc = 3683724| bibcode = 2013PNAS..110.9824F | doi-access = free }}</ref> (for comparison, that is approximately the number of atoms in a [[ton]] of [[gold]]).  ''Prochlorococcus'' is ubiquitous between 40°N and 40°S and dominates in the [[oligotroph]]ic (nutrient-poor) regions of the oceans.<ref name="Partensky" />  ''Prochlorococcus'' is mostly found in a temperature range of 10–33&nbsp;°C and some strains can grow at depths with low light (<1% surface light).<ref name="Munn"/> These strains are known as LL (Low Light) ecotypes, with strains that occupy shallower depths in the water column known as HL (High Light) ecotypes.<ref>{{cite journal | last1 = Coleman | first1 = M. | last2 = Sullivan | first2 = M. | last3 = Martiny | first3 = A. | last4 = Steglich | first4 = C. | last5 = Barry | first5 = K. | last6 = DeLong | first6 = E. | last7 = Chisholm | first7 = S. | year = 2006 | title = Genomic islands and the ecology and evolution of ''Prochlorococcus'' | url = http://www.escholarship.org/uc/item/6506g5sk| journal = Science | volume = 311 | issue = 5768| pages = 1768–70 | doi=10.1126/science.1122050 | pmid=16556843| bibcode = 2006Sci...311.1768C | s2cid = 3196592 | url-access = subscription }}</ref> Furthermore, ''Prochlorococcus'' are more plentiful in the presence of heterotrophs that have catalase abilities.<ref name="ROS">{{cite journal|last1=Morris|first1=J. J.|last2=Kirkegaard|first2=R.|last3=Szul|first3=M. J.|last4=Johnson|first4=Z. I.|last5=Zinser|first5=E. R.|title=Facilitation of Robust Growth of ''Prochlorococcus'' Colonies and Dilute Liquid Cultures by "Helper" Heterotrophic Bacteria|journal=Applied and Environmental Microbiology|date=23 May 2008|volume=74|issue=14|pages=4530–4|doi=10.1128/AEM.02479-07|pmid=18502916|pmc=2493173|bibcode=2008ApEnM..74.4530M}}</ref> ''Prochlorococcus'' do not have mechanisms to degrade reactive oxygen species and rely on heterotrophs to protect them.<ref name="ROS" /> The bacterium accounts for an estimated 13–48% of the global photosynthetic production of [[oxygen]], and forms part of the base of the ocean [[food chain]].<ref name="Niche Partitioning">{{cite journal|last1=Johnson|first1=Zachary I.|last2=Zinser|first2=Erik R.|last3=Coe|first3=Allison|last4=McNulty|first4=Nathan P.|last5=Woodward|first5=E. Malcolm S.|last6=Chisholm|first6=Sallie W.|title=Niche Partitioning among ''Prochlorococcus'' Ecotypes along Ocean-Scale Environmental Gradients|journal=Science|date=2006|volume=311|issue=5768|pages=1737–40|doi=10.1126/science.1118052|pmid=16556835|bibcode=2006Sci...311.1737J|s2cid=3549275}}</ref>