AUTHOR=Fourquez Marion , Beier Sara , Jongmans Elanor , Hunter Robert , Obernosterer Ingrid TITLE=Uptake of Leucine, Chitin, and Iron by Prokaryotic Groups during Spring Phytoplankton Blooms Induced by Natural Iron Fertilization off Kerguelen Island (Southern Ocean) JOURNAL=Frontiers in Marine Science VOLUME=3 YEAR=2016 URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2016.00256 DOI=10.3389/fmars.2016.00256 ISSN=2296-7745 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 (