Southern Ocean phytoplankton turnover in response to stepwis

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TitleSouthern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million yearsAbstractIt is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate bÌaseline Ìvariability on glacial-interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations. Copyright 2016, National Academy of Sciences. All rights reserved.AcknowledgementsWe gratefully acknowledge the constructive reviews of two anonymous referees and the journal editor, all of which improved the final paper. We thank Peter Sadler, who developed the CONOP program, made this freely available, and contributed advice during analysis. Scientific research was supported jointly by the Sarah Beanland Memorial Scholarship (R.D.C.); New Zealand Ministry of Business, Innovation and Employment Contract C05X1001 (to J.S.C., R.L., and R.M.); New Zealand Antarctic Research Institute Grant NZARI 2013-1 (to R.L. and R.M.); Rutherford Discovery Fellowship RDF-13-VUW-003 (to R.M.), and the US National Science Foundation Cooperative Agreement 0342484 to the University of Nebraska--Lincoln (to D.H.).

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1st AuthorCrampton, J.AuthorCrampton, J.Cody, R.Levy, R.Harwood, D.McKay, R.Naish, T.Year2016JournalProceedings of the National Academy of Sciences of the United States of AmericaVolume113Number25Pages6868-6873DOI10.1073/pnas.1600318113URLhttps://www.scopus.com/inward/recor.....95580559db5e68e53e6c1bbe9KeywordsAntarcticaArticleclimate changecoolingdiatomglaciationhabitatice sheetlatitudeMiddle Miocenemodelphytoplanktonpriority journalsea icespecies differentiationturnover timewater temperature, rank4Author KeywordsAntarcticaDiatomsMiocenePhytoplanktonPliocene

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TypeArticleCitationCrampton, J., Cody, R., Levy, R., Harwood, D., McKay, R. and Naish, T. (2016). Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years. Proceedings of the National Academy of Sciences of the United States of America, 113(25): 6868-6873 IdentifierCrampton2016Relevancerank4