Publication Date:
2022-05-26
Description:
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 8 (2017): 2117, doi:10.3389/fmicb.2017.02117.
Description:
Bacterial consumption of dissolved organic matter (DOM) drives much of the movement of carbon through the oceanic food web and the global carbon cycle. Understanding complex interactions between bacteria and marine DOM remains an important challenge. We tested the hypothesis that bacterial growth and community succession would respond differently to DOM additions due to seasonal changes in phytoplankton abundance in the environment. Four mesocosm experiments were conducted that spanned the spring transitional period (August–December 2013) in surface waters of the Western Antarctic Peninsula (WAP). Each mesocosm consisted of nearshore surface seawater (50 L) incubated in the laboratory for 10 days. The addition of DOM, in the form of cell-free exudates extracted from Thalassiosira weissflogii diatom cultures led to changes in bacterial abundance, production, and community composition. The timing of each mesocosm experiment (i.e., late winter vs. late spring) influenced the magnitude and direction of bacterial changes. For example, the same DOM treatment applied at different times during the season resulted in different levels of bacterial production and different bacterial community composition. There was a mid-season shift from Collwelliaceae to Polaribacter having the greatest relative abundance after incubation. This shift corresponded to a modest but significant increase in the initial relative abundance of Polaribacter in the nearshore seawater used to set up experiments. This finding supports a new hypothesis that starting community composition, through priority effects, influenced the trajectory of community succession in response to DOM addition. As strong inter-annual variability and long-term climate change may shift the timing of WAP phytoplankton blooms, and the corresponding production of DOM exudates, this study suggests a mechanism by which different seasonal successional patterns in bacterial communities could occur.
Description:
CL was partially funded by the Graduate School and the
Department of Ecology and Evolutionary Biology at Brown
University and the Brown University-Marine Biological
Laboratory Joint Graduate Program. This material is based upon
work supported by the National Science Foundation under Grant
Nos. ANT-1142114 to LA-Z, OPP-0823101 and PLR-1440435
to HD, and ANT-1141993 to JR. The Gordon and Betty Moore
Foundation grant 1711 supported work by DR.
Keywords:
16S rRNA
;
Amplicon sequencing
;
Community assembly
;
Bacterial succession
;
Mesocosms
;
Collwelliaceae
;
Polaribacter
;
Phytoplankton exudates
Repository Name:
Woods Hole Open Access Server
Type:
Article
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