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An integrated response of Trichodesmium erythraeum IMS101 growth and photo-physiology to Iron, CO2, and light intensity

An integrated response of Trichodesmium erythraeum IMS101 growth and photo-physiology to Iron, CO2, and light intensity
An integrated response of Trichodesmium erythraeum IMS101 growth and photo-physiology to Iron, CO2, and light intensity

We have assessed how varying CO2 (180, 380, and 720 μatm) and growth light intensity (40 and 400 μmol photons m-2 s-1) affected Trichodesmium erythraeum IMS101 growth and photophysiology over free iron (Fe') concentrations between 20 and 9,600 pM. We found significant iron dependencies of growth rate and the initial slope and maximal relative PSII electron transport rates (rPm). Under iron-limiting concentrations, high-light increased growth rates and rPm; possibly indicating a lower allocation of resources to iron-containing photosynthetic proteins. Higher CO2 increased growth rates across all iron concentrations, enabled growth to occur at lower Fe' concentrations, increased rPm and lowered the iron half saturation constants for growth (Km). We attribute these CO2 responses to the operation of the CCM and the ATP spent/saved for CO2 uptake and transport at low and high CO2, respectively. It seems reasonable to conclude that T. erythraeum IMS101 can exhibit a high degree of phenotypic plasticity in response to CO2, light intensity and iron-limitation. These results are important given predictions of increased dissolved CO2 and water column stratification (i.e., higher light exposures) over the coming decades.

CO, Cyanobacteria, Electron transport rates, Fluorescence light curves, Iron limitation, Light intensity, Ocean acidification, Trichodesmium erythraeum
1664-302X
1-12
Boatman, Tobias G.
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Oxborough, Kevin
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Gledhill, Martha
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Lawson, Tracy
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Geider, Richard J.
f1432d5c-8c1d-48ab-ac52-e81ee5ce7f42
Boatman, Tobias G.
1319e6c9-b464-46d4-910c-440fd3e4587a
Oxborough, Kevin
16d1da54-ed48-400e-9acf-d03536a1401e
Gledhill, Martha
da795c1e-1489-4d40-9df1-fc6bde54382d
Lawson, Tracy
6b62f544-1615-4620-b2f2-a3ce846495b7
Geider, Richard J.
f1432d5c-8c1d-48ab-ac52-e81ee5ce7f42

Boatman, Tobias G., Oxborough, Kevin, Gledhill, Martha, Lawson, Tracy and Geider, Richard J. (2018) An integrated response of Trichodesmium erythraeum IMS101 growth and photo-physiology to Iron, CO2, and light intensity. Frontiers in Microbiology, 9 (APR), 1-12. (doi:10.3389/fmicb.2018.00624).

Record type: Article

Abstract

We have assessed how varying CO2 (180, 380, and 720 μatm) and growth light intensity (40 and 400 μmol photons m-2 s-1) affected Trichodesmium erythraeum IMS101 growth and photophysiology over free iron (Fe') concentrations between 20 and 9,600 pM. We found significant iron dependencies of growth rate and the initial slope and maximal relative PSII electron transport rates (rPm). Under iron-limiting concentrations, high-light increased growth rates and rPm; possibly indicating a lower allocation of resources to iron-containing photosynthetic proteins. Higher CO2 increased growth rates across all iron concentrations, enabled growth to occur at lower Fe' concentrations, increased rPm and lowered the iron half saturation constants for growth (Km). We attribute these CO2 responses to the operation of the CCM and the ATP spent/saved for CO2 uptake and transport at low and high CO2, respectively. It seems reasonable to conclude that T. erythraeum IMS101 can exhibit a high degree of phenotypic plasticity in response to CO2, light intensity and iron-limitation. These results are important given predictions of increased dissolved CO2 and water column stratification (i.e., higher light exposures) over the coming decades.

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fmicb-09-00624
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Accepted/In Press date: 19 March 2018
e-pub ahead of print date: 10 April 2018
Keywords: CO, Cyanobacteria, Electron transport rates, Fluorescence light curves, Iron limitation, Light intensity, Ocean acidification, Trichodesmium erythraeum

Identifiers

Local EPrints ID: 419982
URI: https://eprints.soton.ac.uk/id/eprint/419982
ISSN: 1664-302X
PURE UUID: cfe6a4e7-1743-4c7c-ba5f-75bfebcf8cb3

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Date deposited: 25 Apr 2018 16:30
Last modified: 13 Mar 2019 18:34

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