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| Titel |
Diversity of cultured photosynthetic flagellates in the northeast Pacific and Arctic Oceans in summer |
| VerfasserIn |
S. Balzano, P. Gourvil, R. Siano, M. Chanoine, D. Marie, S. Lessard, D. Sarno, D. Vaulot |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 11 ; Nr. 9, no. 11 (2012-11-16), S.4553-4571 |
| Datensatznummer |
250007396
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| Publikation (Nr.) |
 copernicus.org/bg-9-4553-2012.pdf |
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| Zusammenfassung |
| During the MALINA cruise (summer 2009), an extensive effort was undertaken to
isolate phytoplankton strains from the northeast (NE) Pacific Ocean, the
Bering Strait, the Chukchi Sea, and the Beaufort Sea. In order to
characterise the main photosynthetic microorganisms occurring in the Arctic
during the summer season, strains were isolated by flow cytometry sorting
(FCS) and single cell pipetting before or after phytoplankton enrichment of
seawater samples. Strains were isolated both onboard and back in the
laboratory and cultured at 4 °C under light/dark conditions. Overall, we
isolated and characterised by light microscopy and 18 S rRNA gene sequencing
104 strains of photosynthetic flagellates which grouped into 21 genotypes
(defined by 99.5% 18 S rRNA gene sequence similarity), mainly affiliated to
Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an
Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas), which was nearly the only
phytoplankter recovered within the picoplankton (< 2 μm) size range.
Strains of Arctic Micromonas as well as other strains from the same class
(Mamiellophyceae) were identified in further detail by sequencing the
internal transcribed spacer (ITS) region of the rRNA operon. The MALINA
Micromonas strains share identical 18 S rRNA and ITS sequences suggesting high genetic
homogeneity within Arctic Micromonas. Three other Mamiellophyceae strains likely
belong to a new genus. Other green algae from the genera Nephroselmis, Chlamydomonas, and Pyramimonas were also
isolated, whereas Heterokontophyta included some unidentified Pelagophyceae,
Dictyochophyceae (Pedinellales), and Chrysophyceae (Dinobryon faculiferum). Moreover, we isolated
some Cryptophyceae (Rhodomonas sp.) as well as a few Prymnesiophyceae and
dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by scanning electron
microscopy (SEM) and 28 S rRNA gene sequencing. Our morphological analyses
show that this species possess the diagnostic features of the genus
Biecheleria, and the 28 S rRNA gene topology corroborates this affiliation. We thus
propose the transfer of W. cincta to the genus Biecheleria and its recombination as Biecheleria cincta. |
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