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Community differentiation and population enrichment of S argasso S ea bacterioplankton in the euphotic zone of a mesoscale mode‐water eddy
Author(s) -
Nelson Craig E.,
Carlson Craig A.,
Ewart Courtney S.,
Halewood Elisa R.
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12241
Subject(s) - bacterioplankton , photic zone , phytoplankton , biology , oceanography , eddy , mesopelagic zone , diatom , bloom , ecology , pelagic zone , nutrient , geology , geography , meteorology , turbulence
Summary Eddies are mesoscale oceanographic features (∼ 200 km diameter) that can cause transient blooms of phytoplankton by shifting density isoclines in relation to light and nutrient resources. To better understand how bacterioplankton respond to eddies, we examined depth‐resolved distributions of bacterial populations across an anticyclonic mode‐water eddy in the S argasso S ea. Previous work on this eddy has documented elevated phytoplankton productivity and diatom abundance within the eddy centre with coincident bacterial productivity and biomass maxima. We illustrate bacterial community shifts within the eddy centre, differentiating populations uplifted along isopycnals from those enriched or depleted at horizons of enhanced bacterial and primary productivity. Phylotypes belonging to the R oseobacter, OCS 116 and marine A ctinobacteria clades were enriched in the eddy core and were highly correlated with pigment‐based indicators of diatom abundance, supporting developing hypotheses that members of these clades associate with phytoplankton blooms. Typical mesopelagic clades ( SAR 202, SAR 324, SAR 406 and SAR 11 IIb ) were uplifted within the eddy centre, increasing bacterial diversity in the lower euphotic zone. Typical surface oligotrophic clades ( SAR 116, OM 75, P rochlorococcus and SAR 11 Ia ) were relatively depleted in the eddy centre. The biogeochemical context of a bloom‐inducing eddy provides insight into the ecology of the diverse uncultured bacterioplankton dominating the oligotrophic oceans.