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Uptake of leucine, chitin, and iron by prokaryotic groups during spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island (Southern Ocean)

Citation

Fourquez, M and Beier, S and Jongmans, E and Hunter, R and Obernosterer, I, Uptake of leucine, chitin, and iron by prokaryotic groups during spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island (Southern Ocean), Frontiers in Marine Science, 3 Article 256. ISSN 2296-7745 (2016) [Refereed Article]


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Copyright Statement

Copyright 2016 the authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.

DOI: doi:10.3389/fmars.2016.00256

Abstract

Iron and carbon are essential for microbial heterotrophic activity, but the bioavailability of these elements is low in surface waters of the Southern Ocean. Whether the access to iron and carbon differs among phylogenetic groups of prokaryotes is barely known. To address this question we used iron (55FeCl3), and the carbon compounds chitin (3H-Diacetylchitobiose) and leucine (3H-leucine) as model substrates in combination with MICRO-CARD-FISH during spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island (KErguelen Ocean and Plateau compared Study 2—KEOPS2; October-November 2011). The application of probes at broad phylogenetic levels indicated an overall similar community composition in surface waters at the 8 investigated sites. The relative contributions of the prokaryotic groups to abundance revealed a strong positive relationship with their respective contributions to the leucine-active community (p < 0.0001; r = 0.93). This relationship was much weaker for chitin (p < 0.001; r = 0.51) and absent for iron (p > 0.05; r = 0.26). These results suggest preferential uptake of iron and chitin by some prokaryotic groups. SAR11 and Cytophaga-Flavobacterium-Bacteroides (CFB) were the dominant contributors to the leucine-active community, while CFB and Archaea had the highest contributions to the chitin-active community. By contrast, Gammaproteobacteria, including SAR86, and CFB revealed the highest contributions to the iron-active community. We found several correlations between the group-specific fractions of active cells for a given substrate and most of them included CFB, pointing to the potential importance of microbial interactions for iron and carbon cycling in the Southern Ocean.

Item Details

Item Type:Refereed Article
Keywords:phytoplankton, iron fertilization, Kerguelen, Southern Ocean, prokaryotes
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Environment
Objective Group:Other Environment
Objective Field:Antarctic and Sub-Antarctic Oceanography
Author:Fourquez, M (Dr Marion Fourquez)
ID Code:114475
Year Published:2016
Deposited By:Centre for Oceans and Cryosphere
Deposited On:2017-02-16
Last Modified:2017-04-10
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