RT Journal Article
SR Electronic
T1 Global distribution patterns of marine nitrogen-fixers by imaging and molecular methods
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.10.17.343731
DO 10.1101/2020.10.17.343731
A1 Juan José Pierella Karlusich
A1 Eric Pelletier
A1 Madeline Carsique
A1 Etienne Dvorak
A1 Sébastien Colin
A1 Marc Picheral
A1 Rainer Pepperkok
A1 Eric Karsenti
A1 Colomban de Vargas
A1 Fabien Lombard
A1 Patrick Wincker
A1 Chris Bowler
A1 Rachel A Foster
YR 2020
UL http://biorxiv.org/content/early/2020/10/17/2020.10.17.343731.abstract
AB Biological nitrogen fixation sustains ~50% of ocean primary production. However, our understanding of marine N2-fixers (diazotrophs) is hindered by limited observations. Here, we developed a quantitative image analysis pipeline in concert with mapping of molecular markers for mining >2,000,000 images and >1,300 metagenomes from Tara Oceans, covering surface, deep chlorophyll maximum and mesopelagic layers across 6 organismal size fractions (0-2000 μm). Imaging and molecular data were remarkably congruent. Diazotrophs were detected from ultrasmall bacterioplankton (<0.2 μm) to mesoplankton (180 to 2000 μm). We identified several new high density regions of diazotrophs. Distributional and abundance patterns support the previous canonical view that larger sized diazotrophs (>10 μm) dominate the tropical belts, while unicellular diazotrophs were found in surface and mesopelagic samples. Multiple co-occurring diazotrophic lineages were frequently encountered, suggesting that complex overlapping niches are common. Overall, this work provides an updated global snapshot of marine diazotroph biogeographical diversity and highlights new sources and sinks of diazotroph-fueled new production.Competing Interest StatementThe authors have declared no competing interest.