Resource Colimitation Drives Competition Between Phytoplankton and Bacteria in the Southern Ocean

Ratnarajah, Lavenia, Blain, Stephane, Boyd, Philip W, Fourquez, Marion, Obernosterer, Ingrid and Tagliabue, Alessandro ORCID: 0000-0002-3572-3634 (2021) Resource Colimitation Drives Competition Between Phytoplankton and Bacteria in the Southern Ocean. GEOPHYSICAL RESEARCH LETTERS, 48 (1). e2020GL088369-.

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Official URL: http://dx.doi.org/10.1029/2020gl088369

Abstract

Across the Southern Ocean, phytoplankton growth is governed by iron and light, while bacterial growth is regulated by iron and labile dissolved organic carbon (LDOC). We use a mechanistic model to examine how competition for iron between phytoplankton and bacteria responds to changes in iron, light, and LDOC. Consistent with experimental evidence, increasing iron and light encourages phytoplankton dominance, while increasing LDOC and decreasing light favors bacterial dominance. Under elevated LDOC, bacteria can outcompete phytoplankton for iron, most easily under lower iron. Simulations reveal that bacteria are major iron consumers and suggest that luxury storage plays a key role in competitive iron uptake. Under seasonal conditions typical of the Southern Ocean, sources of LDOC besides phytoplankton exudation modulate the strength of competitive interactions. Continued investigations on the competitive fitness of bacteria in driving changes in primary production in iron-limited systems will be invaluable in refining these results.

Item Type:	Article
Uncontrolled Keywords:	bacteria, competition, iron, phytoplankton, Southern Ocean
Divisions:	Faculty of Science and Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	03 Sep 2021 07:35
Last Modified:	18 Jan 2023 21:30
DOI:	10.1029/2020GL088369
Open Access URL:	https://doi.org/10.1029/2020GL088369
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3135725