The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera

© 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. The attached file is the published version of the article

Hydrography shapes bacterial biogeography of the Deep Arctic Ocean

13 páginas, 5 figuras, 2 tablas.It has been long debated as to whether marine microorganisms have a ubiquitous distribution or patterns of biogeography, but recently a consensus for the existence of microbial biogeography is emerging. However, the factors controlling the distribution of marine bacteria remain poorly understood. In this study, we combine pyrosequencing and traditional Sanger sequencing of the 16S rRNA gene to describe in detail bacterial communities from the deep Arctic Ocean. We targeted three separate water masses, from three oceanic basins and show that bacteria in the Arctic Ocean have a biogeography. The biogeographical distribution of bacteria was explained by the hydrography of the Arctic Ocean and subsequent circulation of its water masses. Overall, this first taxonomic description of deep Arctic bacteria communities revealed an abundant presence of SAR11 (Alphaproteobacteria), SAR406, SAR202 (Chloroflexi) and SAR324 (Deltaproteobacteria) clusters. Within each cluster, the abundance of specific phylotypes significantly varied among water masses. Water masses probably act as physical barriers limiting the dispersal and controlling the diversity of bacteria in the ocean. Consequently, marine microbial biogeography involves more than geographical distances, as it is also dynamically associated with oceanic processes. Our ocean scale study suggests that it is essential to consider the coupling between microbial and physical oceanography to fully understand the diversity and function of marine microbes.Financial and ship time support from Fisheries and Oceans Canada and the Canadian International Polar Year Program’s Canada’s Three Oceans project and the Nansen and Amundsen Basins Observational System project. PE Galand was supported by a Marie Curie Grant (CRENARC MEIF-CT-2007-040247) and EO Casamayor by the Spanish Grant CGL2006-12058-BOS. C Lovejoy would like to acknowledge the support of the Natural Sciences and Engineering Council, Canada (NSERC) Special Research Opportunity Fund and ArcticNet. Deep Arctic samples were collected by K Scarcella, E Didierjean and M-E´ Garneau. Pyrosequencing was supported by a Keck foundation grant to M Sogin and L Ameral Zettler. This is a contribution to the International Census of Marine Microbes (ICOMM).Peer reviewe