Prochlorococcus marinus

Overview

Rocap and colleagues described this single-celled cyanobacterium as a photosynthetic contributor in tropical and subtropical seas, where high-light and low-light forms occupy different depths of the sunlit water column.

Their 2003 comparison found the high-light strain MED4 genome at 1,657,990 base pairs and the low-light strain MIT9313 at 2,410,873, sharing 1,350 genes. Differences reflected gene retention, duplication and lateral acquisition linked to light niche.

Dufresne and colleagues sequenced low-light type strain SS120 (CCMP1375): one circular 1,751,080-base-pair chromosome, 36.4% G+C, and 1,884 predicted protein-coding genes. It lacked many genes conserved in other cyanobacteria, notably signal-transduction and stress-response components.

Origins & earliest records

The chronology of the original species description is unverified in the supplied sources.

Evidence & interpretation

Based on an opened Nature abstract (Rocap et al. 2003) and indexed PNAS text (Dufresne et al. 2003).

Selected bibliography

Documented works and useful reading. This is not a list of every appearance.

1. 01

   Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiation

   Rocap et al. · 2003

   Selected bibliography; Nature 424:1042–1047, MED4 and MIT9313 comparison.

2. 02

   Genome sequence of the cyanobacterium Prochlorococcus marinus SS120, a nearly minimal oxyphototrophic genome

   Dufresne et al. · 2003

   Selected bibliography; PNAS 100:10020–10025, type strain genome.

Family, evolution & connections

Taxonomic classification

A hierarchy of classified groups, not a chain of direct ancestors.

Source note: Ranked groups in the NCBI Taxonomy snapshot accessed 7 October 2026; these are not identified direct ancestors. NCBI provides a database classification rather than an independent nomenclatural authority.

1. domainBacteria
2. kingdomBacillati
3. phylumCyanobacteriota
4. classCyanophyceae
5. orderSynechococcales
6. familyProchlorococcaceae
7. genusProchlorococcus
8. speciesProchlorococcus marinus

References

Sources supporting this profile. Linked pages have their own scope and editorial standards.

1. Scientific paper (publisher abstract)Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiationResearch access: 2026-10-06
2. Scientific paper (indexed text)Genome sequence of the cyanobacterium Prochlorococcus marinus SS120, a nearly minimal oxyphototrophic genomeResearch access: 2026-10-06
3. Scientific classification referenceNCBI Taxonomy: Prochlorococcus marinusResearch access: 2026-10-07

Image credits

A sourced illustration has not yet been added. This gap is included in the coverage record.