A laboratory study on O2 dynamics and photosynthesis in ice algal communities: Quantification by microsensors, O2 exchange rates, 14C incubations and a PAM fluorometer

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dc.contributor.author Glud, RN
dc.contributor.author Rysgaard, S
dc.contributor.author Kühl, M
dc.date.accessioned 2012-02-02T06:46:37Z
dc.date.issued 2002-04-16
dc.identifier.citation Aquatic Microbial Ecology, 2002, 27 (3), pp. 301 - 311
dc.identifier.issn 0948-3055
dc.identifier.other C1UNSUBMIT en_US
dc.identifier.uri http://hdl.handle.net/10453/14801
dc.description.abstract The present study compared O2 exchange measurements, fluorometry and 14c incubations for measuring productivity of sea-ice algae. It is demonstrated that brine leaking out of ice during freezing conditions is supersaturated with respect to O2, while the melting water released during thawing is undersaturated with O2. This results in a highly variable O2 concentration at the ice-water interface during expanding or shrinking of sea ice. Consequently, great care should be taken when inferring biological activity from O2 exchange rates, whether they are obtained via microprofiles, bulk incubations or direct measurement of O2 concentrations in water below sea ice. Accounting for the O2 dynamics related to changes in sea-ice structure, the photosynthetic activity of a mixed ice algal culture, as measured by net O2 exchange rates and 14C incubation, co-varied as a function of biomass and irradiance. The ratio between the net O2 efflux and the gross C fixation rate (the photosynthetic quotient) was similar for frozen and non-frozen ice algal communities and averaged 1.43 ± 0.48. Quantification of the relative electron transport rate (ETR) from photosystem II (PSII) and the minimum fluorescence yield (F0) by a pulse-amplitude-modulated (PAM) fluorometer offers a fast, simple and non-invasive approach for estimating activity and biomass of ice algal communities. The relative ETR measurements correlated with the other 2 measures for primary production. However, the correlation was non-linear, leading to a poor resolution of the fluorometer approach at higher photosynthetic activities. A similar observation was made for the correlation between measurements and the concentration of chlorophyll a.
dc.language eng
dc.title A laboratory study on O2 dynamics and photosynthesis in ice algal communities: Quantification by microsensors, O2 exchange rates, 14C incubations and a PAM fluorometer
dc.type Journal Article
dc.description.version Published
dc.parent Aquatic Microbial Ecology
dc.journal.volume 3
dc.journal.volume 27
dc.journal.number en_US
dc.publocation Oldendorf, Germany en_US
dc.identifier.startpage 301 en_US
dc.identifier.endpage 311 en_US
dc.cauo.name SCI.Environmental Sciences en_US
dc.conference Verified OK en_US
dc.for 0602 Ecology
dc.personcode 107129
dc.percentage 100 en_US
dc.classification.name Ecology en_US
dc.classification.type FOR-08 en_US
dc.edition en_US
dc.custom en_US
dc.date.activity en_US
dc.location.activity en_US
dc.description.keywords Fluorometer
dc.description.keywords Microelectrodes
dc.description.keywords Oxygen
dc.description.keywords Primary production
dc.description.keywords Pulse amplitude modulated fluorometry
dc.description.keywords Sea-ice algae
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
utslib.copyright.status Closed Access
utslib.copyright.date 2015-04-15 12:17:09.805752+10
pubs.consider-herdc false
utslib.collection.history Closed (ID: 3)

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