Ecogenomic sensor reveals controls on N2-fixing microorganisms in the North Pacific Ocean.
Nitrogen-fixing microorganisms (diazotrophs) are keystone species that reduce atmospheric dinitrogen (N2) gas to fixed nitrogen (N), thereby accounting for much of N-based new production annually in the oligotrophic North Pacific. However, current approaches to study N2 fixation provide relatively limited spatiotemporal sampling resolution; hence, little is known about the ecological controls on these microorganisms or the scales over which they change. In the present study, we used a drifting robotic gene sensor to obtain high-resolution data on the distributions and abundances of N2-fixing populations over small spatiotemporal scales. The resulting measurements demonstrate that concentrations of N2 fixers can be highly variable, changing in abundance by nearly three orders of magnitude in less than 2 days and 30 km. Concurrent shipboard measurements and long-term time-series sampling uncovered a striking and previously unrecognized correlation between phosphate, which is undergoing long-term change in the region, and N2-fixing cyanobacterial abundances. These results underscore the value of high-resolution sampling and its applications for modeling the effects of global change.
1] Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA [2] Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA [3] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA.
Julie C
JC
Robidart
1] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA [2] Department of Oceanography, University of Hawaii, Honolulu, HI, USA.
Matthew J
MJ
Church
Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.
John P
JP
Ryan
1] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA [2] Department of Oceanography, University of Hawaii, Honolulu, HI, USA.
François
F
Ascani
1] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA [2] Department of Oceanography, University of Hawaii, Honolulu, HI, USA.
Samuel T
ST
Wilson
1] Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA [2] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA.
Deniz
D
Bombar
Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.
Roman
R
Marin
1] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA [2] Department of Oceanography, University of Hawaii, Honolulu, HI, USA.
Kelvin J
KJ
Richards
1] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA [2] Department of Oceanography, University of Hawaii, Honolulu, HI, USA.
David M
DM
Karl
1] Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA [2] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA.
Christopher A
CA
Scholin
1] Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA [2] Center for Microbial Oceanography: Research and Education, University of Hawaii, Honolulu, HI, USA.
Jonathan P
JP
Zehr
D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D023281:Genomics; D009586:Nitrogen Fixation; D010140:Pacific Ocean; D016133:Polymerase Chain Reaction; D012371:Robotics; D012623:Seawater / Q000382:microbiology*