ARB analysis of Euks clone libraries (337 sequences).

Done by Daniel (28 dec 00):    Olipac,  Roscoff (April), Helgoland (March, April, Aug),

• Sequence assignement (Excel file)
• Full tree (pdf file)
• Summary of clones (Table below)
• A few selected trees (Fig. 1-4 below)
• Pies showing relative frequency of the differen groups (Fig. 5 below)

A preliminary analysis of clone libraries from Olipac, Roscoff (April) and Helgoland (March, April, Aug) (320 sequences -see Table 1 below) reveals very interesting facts:

• The absence of any diatom sequence demonstrates that the filtration used was pretty efficient to remove large cells.
• The April Roscoff library has fairly low redundancy.  Out of 84 sequences, 77 are unique and only 1 can be assigned to a Metazoa (Cnidarian).
• Some novel sequences are found identical in both Helgoland and Roscoff clone libraries
• Some groups are unique to the coastal environment compared to the Equatorial Pacific this includes:
  • Cryptophytes
  • Prasinophytes from the Mamiellales (Mantionella, Ostreococcus, Bathycococcus see Fig. 1 below).  This confirms FISH data from Fabrice.
  • Some ciliates close to Strombidium (see Fig 2 below)
  • Chrysophytes (some are close to Paraphysomonas)
• In contrast some groups are only found in the OLIPAC oligotrophic libary
  • Acanthareans (this is logical since they are typical blue water organism)
  • Some uncultured Prasinophyte clades
  • Pelagophytes (this is more surprising)
  • A novel group with very unclear affinity (represented respectively by sequences OLI11032 and OLI11016)
• The group of organism close to the parasitic dinoflagellate Amoebophrya detected in the OLIPAC sample is also present in coastal samples (see Fig. 3 below).
• Bolidophytes are present in coastal waters(see Fig. 4 below).  This confirms FISH data from Fabrice (see picture from Roscoff 28 08 00 sample)
• As in the equatorial Pacific very few Prymnesiophytes are found in the coastal libraries.