Neither elevated nor reduced CO 2 affects the photophysiological performance of the marine Antarctic diatom Chaetoceros brevis

Enhanced or reduced pCO(2) (partial pressure of CO2) may affect the photosynthetic performance of marine microalgae since changes in pCO(2) can influence the activity of carbon concentrating mechanisms, modulate cellular RuBisCO levels or alter carbon uptake efficiency. In the present study we compa...

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Bibliographic Details
Published in:Journal of Experimental Marine Biology and Ecology
Main Authors: Boelen, Peter, de Poll, Willem H. van, van der Strate, Han J., Neven, Ika A., Beardall, John, Buma, Anita G. J.
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
Climate change
Dynamic irradiance
Phytoplankton
Southern Ocean
Vertical mixing
Xanthophyll cycling
SOUTHERN-OCEAN
CARBON-DIOXIDE
CONCENTRATING MECHANISMS
MATHEMATICAL-MODEL
EMILIANIA-HUXLEYI
GROWTH-RATE
PHOTOSYNTHESIS
FLUORESCENCE
RUBISCO
Antarctic
The Antarctic
Antarc*
Online Access:https://hdl.handle.net/11370/ca9ddd9f-50b2-4b47-94b4-42eb688af70c
https://research.rug.nl/en/publications/ca9ddd9f-50b2-4b47-94b4-42eb688af70c
https://doi.org/10.1016/j.jembe.2011.06.012
Description
Summary:Enhanced or reduced pCO(2) (partial pressure of CO2) may affect the photosynthetic performance of marine microalgae since changes in pCO(2) can influence the activity of carbon concentrating mechanisms, modulate cellular RuBisCO levels or alter carbon uptake efficiency. In the present study we compared the photophysiology of the Antarctic diatom Chaetoceros brevis at two pCO(2) extremes: 750 ppmv (2x ambient) and 190 ppmv (0.5x ambient) CO2. Cultures were acclimated to four irradiance regimes: two regimes simulating deep or shallow vertical mixing, and two regimes mimicking limiting and saturating stable water column conditions. Then, growth rate, pigmentation, RuBisCO large subunit expression. RuBisCO activity, photosynthesis vs irradiance curves, effective quantum yield of PSII (F-v/F-m), and POC were measured. The four irradiance regimes induced a suite of photophysiological responses, ranging from low light acclimation to efficient photoprotection. Growth was reduced under the low constant and the deep mixing regime, compared to the shallow mixing and the stable saturating regime. Low stable irradiance resulted in higher light harvesting pigment concentrations, lower RuBisCO activity and a lower light saturation point (E-k) compared to the other irradiance regimes. Highest RuBisCO activity as well as P-max levels was measured in the shallow mixing regime, which received the highest total daily light dose. Photoprotection by xanthophyll cycling was observed under all irradiance regimes except the low stable irradiance regime, and xanthophyll cycle pool sizes were higher under the dynamic irradiance regimes. For the fluctuating irradiance regimes. E-v/E-m was hardly affected by previous excess irradiance exposure, suggesting minimal PSII damage. No significant differences between the two pCO(2) levels were found, with respect to growth, pigment content and composition, photosynthesis, photoprotection and RuBisCO activity, for all four irradiance regimes. Thus, within the range tested, pCO(2) does not ...

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