Submesoscale physicochemical dynamics directly shape bacterioplankton community structure in space and time

Author(s)
Eduard Fadeev, Matthias Wietz, Wilken‐Jon von Appen, Morten H. Iversen, Eva‐Maria Nöthig, Anja Engel, Julia Grosse, Martin Graeve, Antje Boetius
Abstract

Submesoscale eddies and fronts are important components of oceanic mixing and energy fluxes. These phenomena occur in the surface ocean for a period of several days, on scales between a few hundred meters and few tens of kilometers. Remote sensing and modeling suggest that eddies and fronts may influence marine ecosystem dynamics, but their limited temporal and spatial scales make them challenging for observation and in situ sampling. Here, the study of a submesoscale filament in summerly Arctic waters (depth 0–400 m) revealed enhanced mixing of Polar and Atlantic water masses, resulting in a ca. 4 km wide and ca. 50 km long filament with distinct physical and biogeochemical characteristics. Compared to the surrounding waters, the filament was characterized by a distinct phytoplankton bloom, associated with depleted inorganic nutrients, elevated chlorophyll a concentrations, as well as twofold higher phyto- and bacterioplankton cell abundances. High-throughput 16S rRNA gene sequencing of bacterioplankton communities revealed enrichment of typical phytoplankton bloom-associated taxonomic groups (e.g., Flavobacteriales) inside the filament. Furthermore, linked to the strong water subduction, the vertical export of organic matter to 400 m depth inside the filament was twofold higher compared to the surrounding waters. Altogether, our results show that physical submesoscale mixing can shape distinct biogeochemical conditions and microbial communities within a few kilometers of the ocean. Hence, the role of submesoscale features in polar waters for surface ocean biodiversity and biogeochemical processes need further investigation, especially with regard to the fate of sea ice in the warming Arctic Ocean.

Organisation(s)
External organisation(s)
Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Max-Planck-Institut für marine Mikrobiologie, Universität Bremen, GEOMAR Helmholtz-Zentrum für Ozeanforschung
Journal
Limnology and Oceanography
Volume
66
Pages
2901-2913
No. of pages
13
ISSN
0024-3590
DOI
https://doi.org/10.1002/lno.11799
Publication date
07-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
106022 Microbiology
ASJC Scopus subject areas
Aquatic Science, Oceanography
Portal url
https://ucris.univie.ac.at/portal/en/publications/submesoscale-physicochemical-dynamics-directly-shape-bacterioplankton-community-structure-in-space-and-time(d8484a20-3279-4e14-9a30-20b03625a149).html