Original Article

Subject Category: Microbial ecology and functional diversity of natural habitats

The ISME Journal (2010) 4, 1044–1052; doi:10.1038/ismej.2010.25; published online 18 March 2010

Diversity of active marine picoeukaryotes in the Eastern Mediterranean Sea unveiled using photosystem-II psbA transcripts

Dikla Man-Aharonovich1,5, Alon Philosof1,5, Benjamin C Kirkup2, Florence Le Gall3, Tali Yogev4, Ilana Berman-Frank4, Martin F Polz2, Daniel Vaulot3 and Oded Béjà1

  1. 1Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
  2. 2Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
  3. 3UPMC (Paris-06) and CNRS, UMR7144, Station Biologique de Roscoff, Roscoff Cedex, France
  4. 4Mina and Everard Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel

Correspondence: O Béjà, Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel. E-mail: beja@tx.technion.ac.il

5These two authors contributed equally to this work.

Received 7 December 2009; Revised 8 February 2010; Accepted 11 February 2010; Published online 18 March 2010.



In vast areas of the oceans, most of the primary production is performed by cells smaller than 2–3μm 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.


picoeukaryotes; PPEs; psbA; transcripts; Mediterranean Sea; diversity