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| Titel |
Distribution and host diversity of Amoebophryidae parasites across oligotrophic waters of the Mediterranean Sea |
| VerfasserIn |
R. Siano, C. Alves-de-Souza, E. Foulon, E. M. Bendif, N. Simon, L. Guillou, F. Not |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2011-02-07), S.267-278 |
| Datensatznummer |
250005440
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| Publikation (Nr.) |
 copernicus.org/bg-8-267-2011.pdf |
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| Zusammenfassung |
| Sequences affiliated to Syndiniales (Marine alveolate, MALV) regularly
dominate 18S rDNA genetic libraries of nearly all marine ecosystems
investigated so far. Among them, Amoebophryidae (MALV group II) is composed
of numerous and genetically distant environmental sequences, where
Amoebophrya is the only known and formally described genus.
Amoebophrya species include virulent
pathogens for a wide range of dinoflagellate species. Beside their regular
occurrence in marine ecosystems, their quantitative distribution and the
environmental factors triggering host infection have barely been studied in
open oligotrophic waters. In order to understand the functional role of
these parasites in natural environments, we studied the distribution and
contribution to the eukaryotic community of the small free-living stage of
Amoebophryidae (the dinospores) along a transect in the Mediterranean Sea,
as well as their host diversity at three oligotrophic stations. Dinospores
were more abundant at a coastal station (max. 1.5 × 103 cells ml−1)
than in oligotrophic waters (max. 51 ± 16.3 cells ml−1),
where they represented 10.3 to 34.9% of the total eukaryotic community at
40 and 30 m depth, respectively and 21.2% on average along the water
column. Positive correlation was found between dinospore occurrence and
higher concentration of NO3 + NO2 at the coastal station. At
selected stations, out of 38 different dinoflagellates taxa identified, 15
were infected, among which a majority were not recognized as Amoebophryidae
host so far. Prevalences (percentage of infected cells) generally varied
between 1% and 10%, with a notable exception for
Blepharocysta paulsenii for which 25% of
cells were infected at the most oligotrophic station. The present study
shows that dinospores are able to thrive and infect dinoflagellates both in
coastal and ultra-oligotrophic open waters. Our results emphasize the role
of parasitism in microbial food web dynamics and ultimately on
biogeochemical cycles. |
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