Bacterioplankton taxa compete for iron along the early spring–summer transition in the Arctic Ocean

• Published in: Ecology and Evolution
• Main Authors: Puente‐Sánchez, Fernando, Macías‐Pérez, Luis Alberto, Campbell, Karley L., Royo‐Llonch, Marta, Balagué, Vanessa, Sánchez, Pablo, Tamames, Javier, Mundy, Christopher John, Pedrós‐Alió, Carlos
• Other Authors: Ministerio de Economía y Competitividad, Vetenskapsrådet, Natural Sciences and Engineering Research Council of Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: Arctic Ocean; Sea ice
• Online Access: http://dx.doi.org/10.1002/ece3.11546; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.11546

Abstract Microbial assemblages under the sea ice of the Dease Strait, Canadian Arctic, were sequenced for metagenomes of a small size fraction (0.2–3 μm). The community from early March was typical for this season, with Alpha ‐ and Gammaproteobacteria as the dominant taxa, followed by Thaumarchaeota and Bacteroidetes. Toward summer, Bacteroidetes, and particularly the genus Polaribacter , became increasingly dominant, followed by the Gammaproteobacteria. Analysis of genes responsible for microbial acquisition of iron showed an abundance of ABC transporters for divalent cations and ferrous iron. The most abundant transporters, however, were the outer membrane TonB‐dependent transporters of iron‐siderophore complexes. The abundance of iron acquisition genes suggested this element was essential for the microbial assemblage. Interestingly, Gammaproteobacteria were responsible for most of the siderophore synthesis genes. On the contrary, Bacteroidetes did not synthesize siderophores but accounted for most of the transporters, suggesting a role as cheaters in the competition for siderophores as public goods. This cheating ability of the Bacteroidetes may have contributed to their dominance in the summer.