Photoprotection of sea-ice microalgal communities from the east antarctic pack ice

Petrou, K; Hill, R; Doblin, MA; McMinn, A; Johnson, R; Wright, SW; Ralph, PJ

Photoprotection of sea-ice microalgal communities from the east antarctic pack ice

Petrou, K

Hill, R

Doblin, MA

McMinn, A Johnson, R Wright, SW Ralph, PJ

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Publication Type:: Journal Article
Citation:: Journal of Phycology, 2011, 47 (1), pp. 77 - 86
Issue Date:: 2011-02-01

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Field	Value	Language
dc.contributor.author	Petrou, K https://orcid.org/0000-0002-2703-0694	en_US
dc.contributor.author	Hill, R https://orcid.org/0000-0002-4623-1563	en_US
dc.contributor.author	Doblin, MA https://orcid.org/0000-0001-8750-3433	en_US
dc.contributor.author	McMinn, A	en_US
dc.contributor.author	Johnson, R	en_US
dc.contributor.author	Wright, SW	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2011-02-01	en_US
dc.identifier.citation	Journal of Phycology, 2011, 47 (1), pp. 77 - 86	en_US
dc.identifier.issn	0022-3646	en_US
dc.identifier.uri	http://hdl.handle.net/10453/14804
dc.description.abstract	All photosynthetic organisms endeavor to balance energy supply with demand. For sea-ice diatoms, as with all marine photoautotrophs, light is the most important factor for determining growth and carbon-fixation rates. Light varies from extremely low to often relatively high irradiances within the sea-ice environment, meaning that sea-ice algae require moderate physiological plasticity that is necessary for rapid light acclimation and photoprotection. This study investigated photoprotective mechanisms employed by bottom Antarctic sea-ice algae in response to relatively high irradiances to understand how they acclimate to the environmental conditions presented during early spring, as the light climate begins to intensify and snow and sea-ice thinning commences. The sea-ice microalgae displayed high photosynthetic plasticity to increased irradiance, with a rapid decline in photochemical efficiency that was completely reversible when placed under low light. Similarly, the photoprotective xanthophyll pigment diatoxanthin (Dt) was immediately activated but reversed during recovery under low light. The xanthophyll inhibitor dithiothreitol (DTT) and state transition inhibitor sodium fluoride (NaF) were used in under-ice in situ incubations and revealed that nonphotochemical quenching (NPQ) via xanthophyll-cycle activation was the preferred method for light acclimation and photoprotection by bottom sea-ice algae. This study showed that bottom sea-ice algae from the east Antarctic possess a high level of plasticity in their light-acclimation capabilities and identified the xanthophyll cycle as a critical mechanism in photoprotection and the preferred means by which sea-ice diatoms regulate energy flow to PSII. © 2011 Phycological Society of America.	en_US
dc.relation	http://purl.org/au-research/grants/arc/DP0773558
dc.relation.ispartof	Journal of Phycology	en_US
dc.relation.isbasedon	10.1111/j.1529-8817.2010.00944.x	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Photoprotection of sea-ice microalgal communities from the east antarctic pack ice	en_US
dc.type	Journal Article
utslib.citation.volume	1	en_US
utslib.citation.volume	47	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	0704 Fisheries Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	open_access
pubs.issue	1	en_US
pubs.publication-status	Published	en_US
pubs.volume	47	en_US

Abstract:

All photosynthetic organisms endeavor to balance energy supply with demand. For sea-ice diatoms, as with all marine photoautotrophs, light is the most important factor for determining growth and carbon-fixation rates. Light varies from extremely low to often relatively high irradiances within the sea-ice environment, meaning that sea-ice algae require moderate physiological plasticity that is necessary for rapid light acclimation and photoprotection. This study investigated photoprotective mechanisms employed by bottom Antarctic sea-ice algae in response to relatively high irradiances to understand how they acclimate to the environmental conditions presented during early spring, as the light climate begins to intensify and snow and sea-ice thinning commences. The sea-ice microalgae displayed high photosynthetic plasticity to increased irradiance, with a rapid decline in photochemical efficiency that was completely reversible when placed under low light. Similarly, the photoprotective xanthophyll pigment diatoxanthin (Dt) was immediately activated but reversed during recovery under low light. The xanthophyll inhibitor dithiothreitol (DTT) and state transition inhibitor sodium fluoride (NaF) were used in under-ice in situ incubations and revealed that nonphotochemical quenching (NPQ) via xanthophyll-cycle activation was the preferred method for light acclimation and photoprotection by bottom sea-ice algae. This study showed that bottom sea-ice algae from the east Antarctic possess a high level of plasticity in their light-acclimation capabilities and identified the xanthophyll cycle as a critical mechanism in photoprotection and the preferred means by which sea-ice diatoms regulate energy flow to PSII. © 2011 Phycological Society of America.

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http://hdl.handle.net/10453/14804