Optical properties of corals distort variable chlorophyll fluorescence measurements

Wangpraseurt, D; Lichtenberg, M; Jacques, SL; Larkum, AWD; Kühl, M

Optical properties of corals distort variable chlorophyll fluorescence measurements

Wangpraseurt, D Lichtenberg, M Jacques, SL Larkum, AWD

Kühl, M

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Publication Type:: Journal Article
Citation:: Plant Physiology, 2019, 179 (4), pp. 1608 - 1619
Issue Date:: 2019-04-01

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Field	Value	Language
dc.contributor.author	Wangpraseurt, D	en_US
dc.contributor.author	Lichtenberg, M	en_US
dc.contributor.author	Jacques, SL	en_US
dc.contributor.author	Larkum, AWD https://orcid.org/0000-0002-0420-134X	en_US
dc.contributor.author	Kühl, M https://orcid.org/0000-0002-1792-4790	en_US
dc.date.available	2019-01-16	en_US
dc.date.issued	2019-04-01	en_US
dc.identifier.citation	Plant Physiology, 2019, 179 (4), pp. 1608 - 1619	en_US
dc.identifier.issn	0032-0889	en_US
dc.identifier.uri	http://hdl.handle.net/10453/136183
dc.description.abstract	© 2019 American Society of Plant Biologists. All rights reserved. Pulse-amplitude–modulated (PAM) fluorimetry is widely used in photobiological studies of corals, as it rapidly provides numerous photosynthetic parameters to assess coral ecophysiology. Coral optics studies have revealed the presence of light gradients in corals, which are strongly affected by light scattering in coral tissue and skeleton. We investigated whether coral optics affects variable chlorophyll (Chl) fluorescence measurements and derived photosynthetic parameters by developing planar hydrogel slabs with immobilized microalgae and with bulk optical properties similar to those of different types of corals. Our results show that PAM-based measurements of photosynthetic parameters differed substantially between hydrogels with different degrees of light scattering but identical microalgal density, yielding deviations in apparent maximal electron transport rates by a factor of 2. Furthermore, system settings such as the measuring light intensity affected F0, Fm, and Fv/Fm in hydrogels with identical light absorption but different degrees of light scattering. Likewise, differences in microalgal density affected variable Chl fluorescence parameters, where higher algal densities led to greater Fv/Fm values and relative electron transport rates. These results have important implications for the use of variable Chl fluorimetry in ecophysiological studies of coral stress and photosynthesis, as well as other optically dense systems such as plant tissue and biofilms.	en_US
dc.relation.ispartof	Plant Physiology	en_US
dc.relation.isbasedon	10.1104/pp.18.01275	en_US
dc.subject.classification	Plant Biology & Botany	en_US
dc.subject.mesh	Animals	en_US
dc.subject.mesh	Anthozoa	en_US
dc.subject.mesh	Chlorophyll	en_US
dc.subject.mesh	Hydrogels	en_US
dc.subject.mesh	Fluorometry	en_US
dc.subject.mesh	Optical Phenomena	en_US
dc.title	Optical properties of corals distort variable chlorophyll fluorescence measurements	en_US
dc.type	Journal Article
utslib.citation.volume	4	en_US
utslib.citation.volume	179	en_US
utslib.for	0606 Physiology	en_US
utslib.for	060204 Freshwater Ecology	en_US
utslib.for	0602 Ecology	en_US
utslib.for	06 Biological Sciences	en_US
utslib.for	07 Agricultural and Veterinary 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/Strength - C3 - Climate Change Cluster
utslib.copyright.status	closed_access
pubs.issue	4	en_US
pubs.publication-status	Published	en_US
pubs.volume	179	en_US

Abstract:

© 2019 American Society of Plant Biologists. All rights reserved. Pulse-amplitude–modulated (PAM) fluorimetry is widely used in photobiological studies of corals, as it rapidly provides numerous photosynthetic parameters to assess coral ecophysiology. Coral optics studies have revealed the presence of light gradients in corals, which are strongly affected by light scattering in coral tissue and skeleton. We investigated whether coral optics affects variable chlorophyll (Chl) fluorescence measurements and derived photosynthetic parameters by developing planar hydrogel slabs with immobilized microalgae and with bulk optical properties similar to those of different types of corals. Our results show that PAM-based measurements of photosynthetic parameters differed substantially between hydrogels with different degrees of light scattering but identical microalgal density, yielding deviations in apparent maximal electron transport rates by a factor of 2. Furthermore, system settings such as the measuring light intensity affected F0, Fm, and Fv/Fm in hydrogels with identical light absorption but different degrees of light scattering. Likewise, differences in microalgal density affected variable Chl fluorescence parameters, where higher algal densities led to greater Fv/Fm values and relative electron transport rates. These results have important implications for the use of variable Chl fluorimetry in ecophysiological studies of coral stress and photosynthesis, as well as other optically dense systems such as plant tissue and biofilms.

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http://hdl.handle.net/10453/136183