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| Titel |
Microbial food web dynamics during spring phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean) |
| VerfasserIn |
U. Christaki, D. Lefèvre, C. Georges, J. Colombet, P. Catala, C. Courties, T. Sime-Ngando, S. Blain, I. Obernosterer |
| 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 ; 11, no. 23 ; Nr. 11, no. 23 (2014-12-05), S.6739-6753 |
| Datensatznummer |
250117714
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| Publikation (Nr.) |
 copernicus.org/bg-11-6739-2014.pdf |
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| Zusammenfassung |
| Microbial food web dynamics were determined during the onset of several
spring phytoplankton blooms induced by natural iron fertilization off
Kerguelen Island in the Southern Ocean (KEOPS2). The abundances of
heterotrophic bacteria and heterotrophic nanoflagellates, bacterial
heterotrophic production, bacterial respiration, and bacterial growth
efficiency, were consistently higher in surface waters of the
iron-fertilized sites than at the reference site in HNLC (high nutrient low
chlorophyll) waters. The abundance of virus-like particles remained
unchanged, but viral production increased by a factor of 6 in
iron-fertilized waters. Bacterial heterotrophic production was significantly
related to heterotrophic nanoflagellate abundance and viral production
across all sites, with bacterial production explaining about 70 and
85%, respectively, of the variance of each in the mixed layer (ML).
Estimated rates of grazing and viral lysis, however, indicated that
heterotrophic nanoflagellates accounted for a substantially higher loss of
bacterial production (50%) than viruses (11%). Combining these results
with rates of primary production and export determined for the study area, a
budget for the flow of carbon through the microbial food web and higher
trophic levels during the early (KEOPS2) and the late phase (KEOPS1) of the
Kerguelen bloom is provided. |
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