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Abstract

Microorganisms confined to annual sea ice in the Southern Ocean are exposed to highly variable oxygen and carbonate chemistry dynamics because of the seasonal increase in biomass and limited exchange with the underlying water column. For sea-ice algae, physiological stress is likely to be exacerbated when the ice melts; however, variation in carbonate speciation has rarely been monitored during this important state-transition. Using pulse amplitude modulated fluorometry (Imaging-PAM, Walz), we documented in situ changes in the maximum quantum yield of photosystem II ( F v / F m ) of sea-ice algae melting out into seawater with initial pH values ranging from 7.66 to 6.39. Although the process of ice-melt elevated seawater pH by 0.2–0.55 units, we observed a decrease in F v / F m between 0.02 and 0.06 for each unit drop in pH during real-time fluorescence imaging. These results are considered preliminary but provide context for including carbonate chemistry monitoring in the design of future sea ice state-transition experiments. Imaging-PAM is a reliable technology for determining F v / F m , but is of limited use for obtaining additional photosynthetic parameters when imaging melting ice.

Item Type:	Article
Authors/Creators:	Castrisios, K and Martin, A and Muller, MN and Kennedy, FC and McMinn, A and Ryan, KG
Keywords:	ice algae pH, Antarctica, imaging-PAM, photophysiology, carbonate chemistry
Journal or Publication Title:	Polar Research
Publisher:	Norwegian Polar Inst
ISSN:	0800-0395
DOI / ID Number:	10.1080/17518369.2018.1438696
Copyright Information:	Copyright 2018 The Authors. Licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0/
Related URLs:	Google Scholar: Martin, A UTAS Profile: Martin, A Google Scholar: McMinn, A UTAS Profile: McMinn, A
Item Statistics:	View statistics for this item

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