Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

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doi: 10.1073/pnas.1600318113
Author(s): Crampton, James S.; Cody, Rosie D.; Levy, Richard H.; Harwood, David; McKay, Robert; Naish, Timothy R.
Author Affiliation(s): Primary:
GNS Science, Department of Paleontology, Lower Hutt, New Zealand
University of Nebraska-Lincoln, United States
Victoria University of Wellington, New Zealand
Volume Title: Proceedings of the National Academy of Sciences of the United States of America
Source: Proceedings of the National Academy of Sciences of the United States of America, 113(25), p.6868-6873. Publisher: National Academy of Sciences, Washington, DC, United States. ISSN: 0027-8424 CODEN: PNASA6
Note: In English. 83 refs.; illus., incl. 2 tables, sketch map
Summary: It 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 "baseline" variability 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.
Year of Publication: 2016
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 09 Paleontology, Paleobotany; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Antarctic ice sheet; Antarctica; Atlantic Ocean; Cenozoic; Climate change; Cooling; DSDP Site 265; DSDP Site 266; DSDP Site 267; DSDP Site 269; DSDP Site 274; Deep Sea Drilling Project; Diatoms; Expedition 318; Extinction; IODP Site U1356; IODP Site U1359; IODP Site U1361; Ice; Indian Ocean; Integrated Ocean Drilling Program; Kerguelen Plateau; Leg 113; Leg 114; Leg 119; Leg 120; Leg 124E; Leg 177; Leg 178; Leg 183; Leg 188; Leg 28; Maud Rise; Microfossils; Mid-Atlantic Ridge; Mid-Indian Ridge; Miocene; Neogene; North Pacific; Northwest Pacific; ODP Site 1093; ODP Site 1094; ODP Site 1096; ODP Site 1101; ODP Site 1138; ODP Site 1165; ODP Site 689; ODP Site 690; ODP Site 693; ODP Site 695; ODP Site 696; ODP Site 699; ODP Site 701; ODP Site 736; ODP Site 737; ODP Site 745; ODP Site 746; ODP Site 747; ODP Site 748; ODP Site 751; ODP Site 774; Ocean Drilling Program; Pacific Ocean; Paleoclimatology; Phytoplankton; Plankton; Plantae; Pliocene; Ross Sea; Scotia Ridge; Sea ice; South Atlantic; Southeast Indian Ridge; Southern Ocean; Speciation; Species turnover; Tertiary; Weddell Sea; West Pacific
Record ID: 2017034566
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Institute of Geological and Nuclear Sciences Limited (GNS Science), Lower Hutt, New Zealand

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