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| Titel |
Fe and C co-limitation of heterotrophic bacteria in the naturally fertilized region off the Kerguelen Islands |
| VerfasserIn |
I. Obernosterer, M. Fourquez, S. Blain |
| 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 ; 12, no. 6 ; Nr. 12, no. 6 (2015-03-26), S.1983-1992 |
| Datensatznummer |
250117882
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| Publikation (Nr.) |
 copernicus.org/bg-12-1983-2015.pdf |
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| Zusammenfassung |
| It has been univocally shown that iron (Fe) is the primary limiting nutrient
for phytoplankton metabolism in high-nutrient, low-chlorophyll (HNLC) waters,
yet the question of how this trace metal affects heterotrophic microbial
activity is far less understood. We investigated the role of Fe for
bacterial heterotrophic production and growth at three contrasting sites in
the naturally Fe-fertilized region east of the Kerguelen Islands and at one site
in HNLC waters during the KEOPS2 (Kerguelen Ocean and Plateau Compared
Study 2) cruise in spring 2011. We performed dark incubations of natural
microbial communities amended either with iron (Fe, as FeCl3) or
carbon (C, as trace-metal clean glucose), or a combination of both, and
followed bacterial abundance and heterotrophic production for up to 7 days.
Our results show that single and combined additions of Fe and C stimulated
bulk and cell-specific bacterial production at the Fe-fertilized sites,
while in HNLC waters only combined additions resulted in significant
increases in these parameters. Bacterial abundance was enhanced in two out of
the three experiments performed in Fe-fertilized waters but did not respond to
Fe or C additions in HNLC waters. Our results provide evidence that both
Fe and C are present at limiting concentrations for bacterial heterotrophic
activity in the naturally fertilized region off the Kerguelen Islands in
spring, while bacteria were co-limited by these elements in HNLC waters.
These results shed new light on the role of Fe in bacterial heterotrophic
metabolism in regions of the Southern Ocean that receive variable Fe inputs. |
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