Carbon dioxide release from the North Pacific abyss during the last deglaciation

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doi: 10.1038/nature06227
Author(s): Galbraith, Eric D.; Jaccard, Samuel L.; Pedersen, Thomas F.; Sigman, Daniel M.; Haug, Gerald H.; Cook, Mea; Southon, John R.; François, Roger
Author Affiliation(s): Primary:
University of British Columbia, Department of Earth & Ocean Sciences, Vancouver, BC, Canada
Other:
University of Victoria, Canada
Princeton University, United States
ETH Zürich, Switzerland
University of California, Santa Cruz, United States
University of California, Irvine, United States
Volume Title: Nature (London)
Source: Nature (London), 449(7164), p.890-894. Publisher: Macmillan Journals, London, United Kingdom. ISSN: 0028-0836 CODEN: NATUAS
Note: In English. 40 refs.; illus., incl. sketch map
Summary: Analyses are summarized of foraminiferal tests separated from cored sediments (ODP Legs 882, 887, 893) at 3.0 to 3.6 km depth in the Gulf of Alaska (sketch map) for 14C, δ13 and δ18O together with sediment analyses for CaCO3, Ba/Al and opal content. The data are plotted against age (up to 30 kyr) and compared to published data for the North Atlantic and Antarctica. Sediments deposited at both sites during the Last Glacial Maximum (LGM) are enriched in authigenic U which precipitates in O-depleted sediments. The export production proxies (Ba/Al and opal) measured in the same sediments show generally reduced fluxes during the last ice age, so that the enhanced U content resulted from lower bottom- water O2, requiring the LGM North Pacific at 3 to 2.6 km depth to have contained higher respired concentrations of C than at present. CaCO3, mainly absent in the cores throughout much of the glacial sediment, appears in abundance ∼ 14.6 kyr ago at each of these three sites, indicating substantially reduced dissolution at the sea floor implying higher bottom water CO3 concentration (due to decreased dissolved inorganic C) and/or increased alkalinity. Other implications of the geochemical data are discussed and overall, the evidence points to a poorly ventilated water mass with high respired CO2 occupying the North Pacific abyss during the LGM, with no improvement in ventilation until ∼ 14 600 yr ago.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Abyssal plains; C-14/C-12; Carbon; Carbon dioxide; Cenozoic; Concentration; Deglaciation; Emperor Seamounts; Foraminifera; Invertebrata; Isotope ratios; Isotopes; Leg 145; Microfossils; North Pacific; Northwest Pacific; O-18/O-16; ODP Site 882; Ocean Drilling Program; Ocean floors; Oxygen; Pacific Ocean; Paleo-oceanography; Paleoatmosphere; Pleistocene; Protista; Quaternary; Radioactive isotopes; Stable isotopes; Upper Pleistocene; West Pacific
Coordinates: N502148 N502148 E1673600 E1673600
Record ID: 2011015371
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom