Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau
| Type | Article | ||||||||||||
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| Date | 2014-12-08 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Malits A.1, 2, Christaki U.3, Obernosterer I.4, 5, Weinbauer M. G.1, 2 | ||||||||||||
| Affiliation(s) | 1 : UPMC Univ Paris 06, Univ Paris 04, UMR7093, LOV Observ Oceanog, F-06230 Villefranche Sur Mer, France. 2 : CNRS, UMR7093, LOV Observ Oceanog, F-06230 Villefranche Sur Mer, France. 3 : Univ Littoral, ULCO, Lab Oceanol & Geosci, INSU CNRS,UMR8187, F-62930 Wimereux, France. 4 : UPMC Univ Paris 06, Univ Paris 04, UMR7621, LOMIC,Observ Oceanog, F-06230 Villefranche Sur Mer, France. 5 : CNRS, UMR 7621, LOMIC, Observ Oceanog, F-66650 Banyuls Sur Mer, France. |
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| Source | Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2014-12-08 , Vol. 11 , N. 23 , P. 6841-6853 | ||||||||||||
| DOI | 10.5194/bg-11-6841-2014 | ||||||||||||
| WOS© Times Cited | 22 | ||||||||||||
| Note | Special issue KEOPS2: Kerguelen Ocean and Plateau Study 2 | ||||||||||||
| Abstract | Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient-low-chlorophyll (HNLC) waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton were 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC) and the fraction of lysogenic cells (FLC) showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over grazing of heterotrophic nanoflagellates (HNFs) during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM) pool with potentially less particulate organic carbon transferred to larger members of the food web or exported. | ||||||||||||
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