Editing Prochlorococcus (section)

== Ecotypes ==
''Prochlorococcus'' has different [[Ecotype|"ecotypes"]] occupying different niches and can vary by pigments, light requirements, nitrogen and phosphorus utilization, copper, and virus sensitivity.<ref name=Scanlan99>{{cite journal |first1=N.J. |last1=West |first2=D.J. |last2=Scanlan |year=1999 |title=Niche-partitioning of ''Prochlorococcus'' in a stratified water column in the eastern North Atlantic Ocean |journal=[[Applied and Environmental Microbiology]] |volume=65 |issue=6 |pages=2585–91 |doi=10.1128/AEM.65.6.2585-2591.1999 |pmc=91382 |pmid=10347047 |doi-access=free}}</ref><ref name="Biller-2014" /><ref name=Rocap03/> It is thought that ''Prochlorococcus'' may occupy potentially 35 different ecotypes and sub-ecotypes within the worlds' oceans. They can be differentiated on the basis of the sequence of the [[ribosomal RNA]] gene.<ref name="Biller-2014" /><ref name=Scanlan99 /> It has been broken down by [[NCBI Taxonomy Browser|NCBI Taxonomy]] into two different subspecies, Low-light Adapted (LL) or High-light Adapted (HL).<ref name="NCBI" /> There are six clades within each subspecies.<ref name="Biller-2014" />

=== Low-light adapted ===
''Prochlorococcus marinus'' subsp. ''marinus'' is associated with low-light adapted types.<ref name="NCBI" /> It is also further classified by sub-ecotypes LLI-LLVII, where LLII/III has not been yet phylogenetically uncoupled.<ref name="Biller-2014" /><ref name="Yan-2020">{{Cite journal |last1=Yan |first1=Wei |last2=Feng |first2=Xuejin |last3=Zhang |first3=Wei |last4=Zhang |first4=Rui |last5=Jiao |first5=Nianzhi |date=2020-11-01 |title=Research advances on ecotype and sub-ecotype differentiation of ''Prochlorococcus'' and its environmental adaptability |url=https://doi.org/10.1007/s11430-020-9651-0 |journal=Science China Earth Sciences |language=en |volume=63 |issue=11 |pages=1691–1700 |doi=10.1007/s11430-020-9651-0 |bibcode=2020ScChD..63.1691Y |s2cid=221218462 |issn=1869-1897|url-access=subscription }}</ref> LV species are found in highly iron scarce locations around the equator, and as a result, have lost several ferric proteins.<ref name="Rusch-2010">{{Cite journal |last1=Rusch |first1=Douglas B. |last2=Martiny |first2=Adam C. |last3=Dupont |first3=Christopher L. |last4=Halpern |first4=Aaron L. |last5=Venter |first5=J. Craig |date=2010-09-14 |title=Characterization of ''Prochlorococcus'' clades from iron-depleted oceanic regions |journal=Proceedings of the National Academy of Sciences |language=en |volume=107 |issue=37 |pages=16184–9 |doi=10.1073/pnas.1009513107 |issn=0027-8424 |pmc=2941326 |pmid=20733077|bibcode=2010PNAS..10716184R |doi-access=free }}</ref> The low-light adapted subspecies is otherwise known to have a higher ratio of chlorophyll b2 to chlorophyll a2,<ref name=Scanlan99 /> which aids in its ability to absorb blue light.<ref>{{cite journal |last1=Ralf |first1=G. |last2=Repeta |first2=D. |year=1992 |title=The pigments of ''Prochlorococcus marinus'': The presence of divinylchlorophyll a and b in a marine prokaryote |journal=Limnology and Oceanography |volume=37 |issue=2 |pages=425–433 |bibcode=1992LimOc..37..425R |doi=10.4319/lo.1992.37.2.0425 |doi-access=free}}</ref> Blue light is able to penetrate ocean waters deeper than the rest of the visible spectrum, and can reach depths of >200&nbsp;m, depending on the turbidity of the water. Their ability to photosynthesize at a depth where blue light penetrates allows them to inhabit depths between 80 and 200 m.<ref name="Martiny" /><ref>{{cite journal |last1=Zinser |first1=E. |last2=Johnson |first2=Z. |last3=Coe |first3=A. |last4=Karaca |first4=E. |last5=Veneziano |first5=D. |last6=Chisholm |first6=S. |year=2007 |title=Influence of light and temperature on Prochlorococcus ecotype distributions in the Atlantic Ocean |journal=Limnology and Oceanography |volume=52 |issue=5 |pages=2205–20 |bibcode=2007LimOc..52.2205Z |doi=10.4319/lo.2007.52.5.2205|s2cid=84767930 |doi-access=free }}</ref> Their genomes can range from 1,650,000 to 2,600,000 basepairs in size.<ref name="Yan-2020" />

=== High-light adapted ===
''Prochlorococcus marinus'' subsp. ''pastoris'' is associated with high-light adapted types.<ref name="NCBI" /> It can be further classified by sub-ecotypes HLI-HLVI.<ref name="Yan-2020" /><ref name="Biller-2014" /> HLIII, like LV, is also located in an iron-limited environment near the equator, with similar ferric adaptations.<ref name="Rusch-2010" /> The high-light adapted subspecies is otherwise known to have a low ratio of chlorophyll b2 to chlorophyll a2.<ref name=Scanlan99 />  High-light adapted strains inhabit depths between 25 and 100&nbsp;m.<ref name="Martiny" /> Their genomes can range from 1,640,000 to 1,800,000 basepairs in size.<ref name="Yan-2020" />