Marine bacteria exhibit a bipolar distribution Journal Article

Authors: Sul, Woo Jun; Oliver, Thomas A.; Ducklow, Hugh W.; Amaral-Zettler, Linda A.; Sogin, Mitchell L.
Article Title: Marine bacteria exhibit a bipolar distribution
Abstract: The microbial cosmopolitan dispersion hypothesis often invoked to explain distribution patterns driven by high connectivity of oceanographic water masses and widespread dispersal ability has never been rigorously tested. By using a global marine bacterial dataset and iterative matrix randomization simulation, we show that marine bacteria exhibit a significantly greater dispersal limitation than predicted by our null model using the “everything is everywhere” tenet with no dispersal limitation scenario. Specifically, marine bacteria displayed bipolar distributions (i.e., species occurring exclusively at both poles and nowhere else) significantly less often than in the null model. Furthermore, we observed fewer taxa present in both hemispheres but more taxa present only in a single hemisphere than expected under the null model. Each of these trends diverged further from the null expectation as the compared habitats became more geographically distant but more environmentally similar. Our meta-analysis supported a latitudinal gradient in bacterial diversity with higher richness at lower latitudes, but decreased richness toward the poles. Bacteria in the tropics also demonstrated narrower latitudinal ranges at lower latitudes and relatively larger ranges in higher latitudes, conforming to the controversial macroecological pattern of the “Rapoport rule.” Collectively, our findings suggest that bacteria follow biogeographic patterns more typical of macroscopic organisms, and that dispersal limitation, not just environmental selection, likely plays an important role. Distributions of microbes that deliver critical ecosystem services, particularly those in polar regions, may be vulnerable to the same impacts that environmental stressors, climate warming, and degradation in habitat quality are having on biodiversity in animal and plant species.
Journal Title: Proceedings of the National Academy of Sciences of the United States of America
Volume: 110
Issue: 6
ISSN: 0027-8424
Publisher: National Academy of Sciences  
Date Published: 2013
Start Page: 2342
End Page: 2347
Woods Hole Authors
  1. Mitchell Sogin
    183 Sogin
  2. Hugh W Ducklow
    165 Ducklow
  3. Woo Jun Sul
    2 Sul
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