The essential micronutrient vitamin B1 (thiamin, B1) can periodically limit microbial communities and bulk productivity, thereby affecting biogeochemical fluxes. In addition, low environmental concentrations of B1 can cause deficiencies in organisms at higher trophic levels. Previous research has shown that the inability to synthesize B1 (auxotrophy) is widespread among prokaryotes and phytoplankton. However, knowledge about B1 bioavailability and microbial physiology related to B1 is limited. To address this, samples were collected from Danish coastal water masses at a seasonal or diurnal temporal resolution. We combined metagenomics, metatranscriptomics and targeted metabolomics to elucidate the detailed cycling of this micronutrient among microbial communities. Genomic and transcriptomic analyses indicated that 80% of the microbial community was auxotrophic for B1. To overcome B1 auxotrophy, prokaryotes expressed specific transporters or enzymes to use B1 related compounds and salvage B1. In some cases, concentrations of B1 or related compounds could be linked to microbial populations or environmental conditions. Overall, only few microbial populations synthesized B1 in Danish coastal waters, these populations varied depending on time or water mass sampled. The combination of multiple ‘omics-based’ datasets allowed a more in depth understanding of B1 dynamics within microbial communities, and how and which microorganisms contribute to the ecosystem function of B1 synthesis.

Primary Presenter: Meriel Bittner, University of Copenhagen (meriel.bittner@bio.ku.dk)

Authors:

Meriel Bittner, University of Copenhagen  (meriel.bittner@bio.ku.dk)

Elden Rowland, Dalhousie University  (Elden.Rowland@Dal.Ca)

Catherine Bannon, Dalhousie University  (cbannon@dal.ca)

John Sundh, Stockholm University  (john.sundh@scilifelab.se)

Erin Bertrand, Dalhousie University  (Erin.Bertrand@dal.ca)

Anders Andersson, KTH Royal Institute of Technology  (anders.andersson@scilifelab.se)

Ryan Paerl, North Carolina State University  (rpaerl@ncsu.edu)

Lasse Riemann, University of Copenhagen  (lriemann@bio.ku.dk)