title: Two modes of change in Southern Ocean productivity over the past million years.
abstract: Export of organic carbon from surface waters of the Antarctic Zone of the Southern Ocean decreased during the last ice age, coinciding with declining atmospheric carbon dioxide (CO(2)) concentrations, signaling reduced exchange of CO(2) between the ocean interior and the atmosphere. In contrast, in the Subantarctic Zone, export production increased into ice ages coinciding with rising dust fluxes, thus suggesting iron fertilization of subantarctic phytoplankton. Here, a new high-resolution productivity record from the Antarctic Zone is compiled with parallel subantarctic data over the past million years. Together, they fit the view that the combination of these two modes of Southern Ocean change determines the temporal structure of the glacial-interglacial atmospheric CO(2) record, including during the interval of "lukewarm" interglacials between 450 and 800 thousand years ago.
authors.affiliation: Geological Institute, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland. samuel.jaccard@erdw.ethz.ch
authors.forename: S L
authors.initials: SL
authors.lastname: Jaccard
authors.forename: C T
authors.initials: CT
authors.lastname: Hayes
authors.forename: A
authors.initials: A
authors.lastname: Martínez-García
authors.forename: D A
authors.initials: DA
authors.lastname: Hodell
authors.forename: R F
authors.initials: RF
authors.lastname: Anderson
authors.forename: D M
authors.initials: DM
authors.lastname: Sigman
authors.forename: G H
authors.initials: GH
authors.lastname: Haug
mesh_terms: D000864:Antarctic Regions; D001272:Atmosphere; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000032:analysis*; D002980:Climate; D019015:Geologic Sediments / Q000737:chemistry; D046448:Ice Cover; D007501:Iron / Q000032:analysis; D009792:Oceans and Seas; D010839:Phytoplankton / Q000254:growth & development / Q000378:metabolism; D012623:Seawater / Q000737:chemistry; D013995:Time
chemical_list: D002245:Carbon Dioxide; D007501:Iron