Non-photochemical quenching of chlorophyll fluorescence and xanthophyll cycle responses after excess PAR and UVR in Chaetoceros brevis, Phaeocystis antarctica and coastal Antarctic phytoplankton

• Published in: Marine Ecology Progress Series
• Main Authors: de Poll, Willem H. van, Lagunas, Marcos, de Vries, Tea, Visser, Ronald J. W., Buma, Anita G. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: Antarctic phytoplankton; Chlorophyll fluorescence; Non-photochemical quenching; Photoacclimation; Ultraviolet radiation; Xanthophyll cycle; SOUTHERN-OCEAN; ULTRAVIOLET-RADIATION; B RADIATION; THALASSIOSIRA-WEISSFLOGII; FRAGILARIOPSIS-CYLINDRUS; DIADINOXANTHIN CYCLE; MARINE DIATOM; POTTER COVE; LIGHT; PHOTOSYNTHESIS; Antarctic; King George Island; Potter Cove; Southern Ocean; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/11370/ddb81820-749b-4ba4-a9b2-a4efba4568a7; https://research.rug.nl/en/publications/ddb81820-749b-4ba4-a9b2-a4efba4568a7; https://doi.org/10.3354/meps09000; https://pure.rug.nl/ws/files/62489546/Non_photochemical_quenching_of_chlorophyll.pdf

Sensitivity to photoinhibition from near-surface irradiance was determined in coastal phytoplankton from Potter Cove (King George Island, Antarctica) in relation to hydrographic conditions shaped by summertime meltwater influx. Slow (indicative for PSII damage) and fast (indicative for xanthophyll cycle activity) relaxing non-photochemical chlorophyll fluorescence quenching (NPQ) was measured during recovery from excess photosynthetically active radiation (PAR) and PAR + ultraviolet radiation (UVR) for 3 stations differentially affected by sediment influx. Additionally, assemblages were incubated outside to study xanthophyll cycle activity during PAR and PAR+UVR exposure. For comparison, NPQ and xanthophyll cycle activity were determined for high (125 mu mol photons m(-2) s(-1)) and low (20 mu mol photons m(-2) s(-1)) light acclimated Chaetoceros brevis (Bacillariophyceae) and Phaeocystis antarctica (Haptophyceae) cultures. Pigment analysis (CHEMTAX) revealed diatom dominance (average 74%) at all locations, with haptophytes being of minor importance (average 13%). All stations were stratified by a vertical density gradient, whereas sediment influx was significantly higher at the innermost station. Taxonomic composition, NPQ characteristics, and photoprotective pigment ratios were not different among stations. At the chlorophyll maximum, phytoplankton showed high light acclimation at all locations, and fast relaxing NPQ dominated after excess PAR and PAR+UVR. Samples from below the chlorophyll maximum were enriched in haptophytes, showed lower photoprotective pigment ratios, reduced capacity for NPQ, and increased contribution of slow relaxing NPQ. The photoprotective capacity of high and low light acclimated C. brevis and P. antarctica differed significantly. P. antarctica induced less NPQ and there was a stronger slow relaxing NPQ component than in the diatom, particularly after low light acclimation. Although total NPQ decreased and slow relaxing NPQ increased after UVR in field samples, NPQ and the ...