In vast areas of the oceans, most of the primary production is performed by cells smaller than 2-3 m in diameter (picophytoplankton). In recent years, several in situ molecular studies showed a broad genetic diversity of small eukaryotes by sequencing 18S rRNA genes. Compared with photosynthetic cyanobacteria that are dominated by two genera, Prochlorococcus and Synechococcus, marine photosynthetic picoeukaryotes (PPEs) are much more diverse, with virtually every algal class being represented. However, the genetic diversity and ecology of PPEs are still poorly described. Here, we show using in situ molecular analyses of psbA transcripts that PPEs in the Eastern Mediterranean Sea are highly diverse, probably very active, and dominated by groups belonging to the red algal lineages, Haptophyta, Heterokontophyta (also called Stramenopiles), and Cryptophyta.
Bibliographical noteFunding Information:
We thank the sequencing team in the MPI for Molecular Genetic in Berlin for technical support and the captain and crew of the R/V Med Explorer for their expert assistance at sea. We are grateful to Feng Chen and Kui Wang for allowing us to use their psbA primers prior to publication and to Ramon Massana for help during the initial stages of the project. This research was supported in part by an Israel Science Foundation Grant (no. 458/04, IB-F & OB), an EMBO YIP award (OB), a Marine Genomics Network Of Excellence EU grant (OB), and a grant by the Gordon and Betty Moore Foundation and US Department of Energy Genomes to Life (MFP). Strains were provided by the Roscoff Culture Collection supported by the Contrat de Plan Etat-Région Souchothèque de Bretagne and by the ASSEMBLE EU FP7 research infrastructure initiative. This research is part of the requirements for a PhD thesis for TY at Bar-Ilan University.
- Mediterranean Sea