Physical and biological controls on DMS,P dynamics in ice sh

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TitlePhysical and biological controls on DMS,P dynamics in ice shelf-influenced fast ice during a winter-spring and a spring-summer transitionsAbstractWe report the seasonal and vertical variations of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) in fast ice at Cape Evans, McMurdo Sound (Antarctica) during the spring-summer transition in 2011 and winter-spring transition in 2012. We compare the variations of DMS,P observed to the seasonal evolution of the ice algal biomass and of the physical properties of the ice cover, with emphasis on the ice texture and brine dynamics. Isolated DMS and DMSP maxima were found during both seasonal episodes in interior ice and corresponded to the occurrence of platelet crystals in the ice texture. We show that platelet crystals formation corresponded in time and depth to the incorporation of dinoflagellates (strong DMSP producers) in the ice cover. We also show that platelet crystals could modify the environmental stresses on algal cells and perturb the vertical redistribution of DMS,P concentrations. We show that during the winter-spring transition in 2012, the DMS,P profiles were strongly influenced by the development and decline of a diatom-dominated bloom in the bottom ice, with DMSP variations remarkably following chl a variations. During the spring-summer transition in 2011, the increase in brine volume fraction (influencing ice permeability) on warming was shown to trigger (1) an important release of DMS to the under-ice water through brine convection and (2) a vertical redistribution of DMSP across the ice. Key Points Incorporated platelet ice can strongly influence fast ice DMS,P dynamics The seasonal bloom of diatoms governs DMSP production in bottom ice Brine convection at the end of spring triggers strong DMS release to the ocean Copyright 2014. American Geophysical Union. All Rights Reserved.AcknowledgementsThe authors would like to thank Brian Staite, Willy Champenois, S ebastien Moreau, and the Scott Base crew for their assistance during field work. We are indebted to Antarctica New Zealand for their logistical support. This research was supported by the FRS-FNRS (project YROSIAE, contract 2.4517.11), Belgian Science Policy (project BIGSOUTH, contract SD/CA/ 05), Antarctica New Zealand (project K131) and the CanadaÅ› National Science and Engineering Research Council (NSERC). Jiayun Zhou and Bruno Delille are PhD student and research associate, respectively, of the FRS and FNRS. This is MARE contribution 264. The authors would also like to thank two anonymous reviewers for their constructive comments. Data can be obtained for free by contacting the lead author.

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1st AuthorCarnat, G.AuthorCarnat, G.Zhou, J.Papakyriakou, T.Delille, B.Goossens, T.Haskell, T.Schoemann, V.Fripiat, F.Rintala, J.-M.Tison, J.-L.Year2014JournalJournal of Geophysical Research: OceansVolume119Number5Pages2882-2905DOI10.1002/2013JC009381URLhttps://www.scopus.com/inward/recor.....8d010d2499b81ada495c3756bKeywordsBiologyDynamicsSea iceTextures, Algal biomassBiological controlsDimethylsulfideDimethylsulfoniopropionateEnvironmental stressMcMurdo soundsPlatelet crystalsVertical variation, Platelets, algabiomassdimethylsulfidedimethylsulfoniopropionatedominanceice coverice shelfseasonal variation, AntarcticaCape EvansEast AntarcticaMcMurdo SoundRoss Island, algaeBacillariophytaDinophyceae, rank5Author KeywordsdimethylsulfideMcMurdo Soundplateletsea iceProgrammeK131 - Sea Ice and Southern Ocean Processes

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TypeArticleCitationCarnat, G., Zhou, J., Papakyriakou, T., Delille, B., Goossens, T., Haskell, T., Schoemann, V., Fripiat, F., Rintala, J.-M. and Tison, J.-L. (2014). Physical and biological controls on DMS,P dynamics in ice shelf-influenced fast ice during a winter-spring and a spring-summer transitions. Journal of Geophysical Research: Oceans, 119(5): 2882-2905 IdentifierCarnat2014Relevancerank5

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K131 - Sea Ice and Southern Ocean Processes