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Biophysical Aspects of Resource Acquisition and Competition in Algal Mixotrophs

Biophysical Aspects of Resource Acquisition and Competition in Algal Mixotrophs
Biophysical Aspects of Resource Acquisition and Competition in Algal Mixotrophs
Mixotrophic organisms combine autotrophic and heterotrophic nutrition and are abundant in both freshwater and marine environments. Recent observations indicate that mixotrophs constitute a large fraction of the biomass, bacterivory, and primary production in oligotrophic environments. While mixotrophy allows greater flexibility in terms of resource acquisition, any advantage must be traded off against an associated increase in metabolic costs, which appear to make mixotrophs uncompetitive relative to obligate autotrophs and heterotrophs. Using an idealized model of cell physiology and community competition, we identify one mechanism by which mixotrophs can effectively outcompete specialists for nutrient elements. At low resource concentrations, when the uptake of nutrients is limited by diffusion toward the cell, the investment in cell membrane transporters can be minimized. In this situation, mixotrophs can acquire limiting elements in both organic and inorganic forms, outcompeting their specialist competitors that can utilize only one of these forms. This advantage can be enough to offset as much as a twofold increase in additional metabolic costs incurred by mixotrophs. This mechanism is particularly relevant for the maintenance of mixotrophic populations and productivity in the highly oligotrophic subtropical oceans.
0003-0147
98-112
Ward, Ben A.
9063af30-e344-4626-9470-8db7c1543d05
Dutkiewicz, Stephanie
a704ddd3-bd6c-4f4a-ba0c-f6420c9c3b3b
Barton, Andrew D.
7ca404e5-783a-47d5-bc18-3a6c47001b20
Follows, Michael J.
12c723bc-f2f8-43f4-a309-bff6885b9c7c
Ward, Ben A.
9063af30-e344-4626-9470-8db7c1543d05
Dutkiewicz, Stephanie
a704ddd3-bd6c-4f4a-ba0c-f6420c9c3b3b
Barton, Andrew D.
7ca404e5-783a-47d5-bc18-3a6c47001b20
Follows, Michael J.
12c723bc-f2f8-43f4-a309-bff6885b9c7c

Ward, Ben A., Dutkiewicz, Stephanie, Barton, Andrew D. and Follows, Michael J. (2011) Biophysical Aspects of Resource Acquisition and Competition in Algal Mixotrophs. The American Naturalist, 178 (1), 98-112. (doi:10.1086/660284).

Record type: Article

Abstract

Mixotrophic organisms combine autotrophic and heterotrophic nutrition and are abundant in both freshwater and marine environments. Recent observations indicate that mixotrophs constitute a large fraction of the biomass, bacterivory, and primary production in oligotrophic environments. While mixotrophy allows greater flexibility in terms of resource acquisition, any advantage must be traded off against an associated increase in metabolic costs, which appear to make mixotrophs uncompetitive relative to obligate autotrophs and heterotrophs. Using an idealized model of cell physiology and community competition, we identify one mechanism by which mixotrophs can effectively outcompete specialists for nutrient elements. At low resource concentrations, when the uptake of nutrients is limited by diffusion toward the cell, the investment in cell membrane transporters can be minimized. In this situation, mixotrophs can acquire limiting elements in both organic and inorganic forms, outcompeting their specialist competitors that can utilize only one of these forms. This advantage can be enough to offset as much as a twofold increase in additional metabolic costs incurred by mixotrophs. This mechanism is particularly relevant for the maintenance of mixotrophic populations and productivity in the highly oligotrophic subtropical oceans.

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Published date: 1 July 2011

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Local EPrints ID: 417050
URI: https://eprints.soton.ac.uk/id/eprint/417050
ISSN: 0003-0147
PURE UUID: 8693b7aa-e63b-4d48-b3be-5b1f1fb0b341

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Date deposited: 18 Jan 2018 17:30
Last modified: 25 Nov 2019 18:31

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