Melting out of sea ice causes greater photosynthetic stress in algae than freezing in

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dc.contributor.author Ralph, PJ
dc.contributor.author Ryan, KG
dc.contributor.author Martin, A
dc.contributor.author Fenton, G
dc.date.accessioned 2009-12-21T02:30:22Z
dc.date.issued 2007-10
dc.identifier.citation Journal of Phycology, 2007, 43 (5), pp. 948 - 956
dc.identifier.issn 0022-3646
dc.identifier.other C1 en_US
dc.identifier.uri http://hdl.handle.net/10453/3856
dc.description.abstract Sea ice is the dominant feature of polar oceans and contains significant quantities of microalgae. When sea ice forms and melts, the microalgal cells within the ice matrix are exposed to altered salinity and irradiance conditions, and subsequently, their photosynthetic apparatuses become stressed. To simulate the effect of ice formation and melting, samples of sea-ice algae from Cape Hallett (Antarctica) were exposed to altered salinity conditions and incubated under different levels of irradiance. The physiological condition of their photosynthetic apparatuses was monitored using fast and slow fluorescence-induction kinetics. Sea-ice algae exhibited the least photosynthetic stress when maintained in 35‰ and 51‰ salinity, whereas 16, 21, and 65‰ treatments resulted in significant photosynthetic stress. The greatest photosynthetic impact appeared on PSII, resulting in substantial closure of PSII reaction centers when exposed to extreme salinity treatments. Salinity stress to sea-ice algae was light dependent, such that incubated samples only suffered photosynthetic damage when irradiance was applied. Analysis of fast-induction curves showed reductions in J, I, and P transients (or steps) associated with combined salinity and irradiance stress. This stress manifests itself in the limited capacity for the reduction of the primary electron receptor, QA, and the plastoquinone pool, which ultimately inhibited effective quantum yield of PSII and electron transport rate. These results suggest that sea-ice algae undergo greater photosynthetic stress during the process of melting into the hyposaline meltwater lens at the ice edge during summer than do microalgae cells during their incorporation into the ice matrix during the process of freezing. © 2007 Phycological Society of America.
dc.language eng
dc.relation.isbasedon 10.1111/j.1529-8817.2007.00382.x
dc.subject Fluorescence, PAM, PEA, Photosystem-Ii Photochemistry, Chlorophyll Fluorescence, Bleaching Conditions, Spirulina-Platensis, Salinity Tolerance, Temperature, Microalgae, Growth, Zooxanthellae, Acclimation, Marine Biology & Hydrobiology
dc.subject Fluorescence; PAM; PEA; Photosystem-Ii Photochemistry; Chlorophyll Fluorescence; Bleaching Conditions; Spirulina-Platensis; Salinity Tolerance; Temperature; Microalgae; Growth; Zooxanthellae; Acclimation; Marine Biology & Hydrobiology
dc.title Melting out of sea ice causes greater photosynthetic stress in algae than freezing in
dc.type Journal Article
dc.parent Journal of Phycology
dc.journal.volume 5
dc.journal.volume 43
dc.journal.number 5 en_US
dc.publocation Oxford, UK en_US
dc.identifier.startpage 948 en_US
dc.identifier.endpage 956 en_US
dc.cauo.name SCI.Environmental Sciences en_US
dc.conference Verified OK en_US
dc.for 0607 Plant Biology
dc.personcode 890085 en_US
dc.personcode 0000022249 en_US
dc.personcode 0000017756 en_US
dc.personcode 0000033213 en_US
dc.percentage 100 en_US
dc.classification.name Plant Biology en_US
dc.classification.type FOR-08 en_US
dc.description.keywords Photosystem-Ii Photochemistry; Chlorophyll Fluorescence; Bleaching Conditions; Spirulina-Platensis; Salinity Tolerance; Temperature; Microalgae; Growth; Zooxanthellae; Acclimation en_US
dc.description.keywords Fluorescence
dc.description.keywords PAM
dc.description.keywords PEA
pubs.embargo.period Not known
pubs.organisational-group /University of Technology Sydney
pubs.organisational-group /University of Technology Sydney/Faculty of Science
pubs.organisational-group /University of Technology Sydney/Strength - C3


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