Acclimation to a dynamic irradiance regime changes excessive irradiance sensitivity of Emiliania huxleyi and Thalassiosira weissflogii

Effects of fluctuating irradiance regimes on excessive photosynthetically active radiation (PAR) and ultraviolet (UV) radiation sensitivity were assessed for Emiliania huxleyi (Lohman) and Thalassiosira weissflogii (Grunow) Fryxell and Hasle. Cultures acclimated to low irradiance were subjected to t...

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Bibliographic Details
Published in:Limnology and Oceanography
Main Authors: van de Poll, Willem H., Visser, Ronald J. W., Buma, Anita G. J.
Format: Article in Journal/Newspaper
Language:English
Published: 2007
Subjects:
ULTRAVIOLET-RADIATION
MARINE DIATOM
FLUCTUATING IRRADIANCE
PIGMENT COMPOSITION
ANTARCTIC DIATOM
CELL-DEATH
PHOTOSYNTHESIS
PHYTOPLANKTON
PHOTOACCLIMATION
GROWTH
Antarctic
Fryxell
Antarc*
Online Access:https://hdl.handle.net/11370/ef65e1a6-45e7-41b0-9452-478f9e70d683
https://research.rug.nl/en/publications/ef65e1a6-45e7-41b0-9452-478f9e70d683
https://doi.org/10.4319/lo.2007.52.4.1430
https://pure.rug.nl/ws/files/6708082/2007LimnolOceanogrvdPoll.pdf
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Summary:Effects of fluctuating irradiance regimes on excessive photosynthetically active radiation (PAR) and ultraviolet (UV) radiation sensitivity were assessed for Emiliania huxleyi (Lohman) and Thalassiosira weissflogii (Grunow) Fryxell and Hasle. Cultures acclimated to low irradiance were subjected to two irradiance regimes of equal daily dose: dynamic irradiance simulating vertical mixing within the water column and constant irradiance. For each regime two irradiance levels were studied. Growth was monitored for 3 d, after which pigment composition was determined. Next, excessive PAR and UV sensitivity was measured by studying viability loss during 4-h exposure to simulated surface irradiance (SSI). Furthermore, the effects of inhibition of D1 reaction center protein turnover were investigated by incubating samples with lincomycin prior to exposure. Dynamic irradiance reduced growth rates of both species as compared to constant irradiance. Pools of light-harvesting pigments increased in dynamic irradiance, whereas the protective pigment pools decreased compared to constant irradiance. Excessive irradiance sensitivity was enhanced in cells grown in fluctuating irradiance. Furthermore, viability loss was most pronounced in UV treatments combined with lincomycin. E. huxleyi was more sensitive to excessive irradiance than T. weissflogii, which coincided with a lower ratio between protective and light-harvesting pigments in the former species. Irradiance modulation by deep vertical mixing influences growth, pigment composition, and excessive PAR and UV sensitivity within days.

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