FN Archimer Export Format
PT J
TI Millennial changes in North Atlantic oxygen concentrations
BT 
AF HOOGAKKER, B. A. A.
   THORNALLEY, D. J. R.
   BARKER, S.
AS 1:1;2:2;3:3;
FF 1:;2:;3:;
C1 Univ Oxford, Dept Earth Sci, Oxford OX1 3AN, England.
   Univ London Univ Coll, Dept Geog, London WC1E 6BT, England.
   Cardiff Univ, Sch Earth & Ocean Sci, Cardiff CF10 3AT, S Glam, Wales.
C2 UNIV OXFORD, UK
   UNIV LONDON UNIV COLL, UK
   UNIV CARDIFF, UK
IN DOAJ
IF 3.851
TC 11
UR https://archimer.ifremer.fr/doc/00353/46416/46157.pdf
   https://archimer.ifremer.fr/doc/00353/46416/46158.pdf
   https://archimer.ifremer.fr/doc/00353/46416/46159.csv
LA English
DT Article
CR IMAGES 1-MD101
BO Marion Dufresne
AB Glacial-interglacial changes in bottom water oxygen concentrations [O-2] in the deep northeast Atlantic have been linked to decreased ventilation relating to changes in ocean circulation and the biological pump (Hoogakker et al., 2015). In this paper we discuss seawater [O-2] changes in relation to millennial climate oscillations in the North Atlantic over the last glacial cycle, using bottom water [O-2] reconstructions from 2 cores: (1) MD95-2042 from the deep northeast Atlantic (Hoogakker et al., 2015) and (2) ODP (Ocean Drilling Program) Site 1055 from the intermediate north-west Atlantic. The deep northeast Atlantic core MD95-2042 shows decreased bottom water [O-2] during millennial-scale cool events, with lowest bottom water [O-2] of 170, 144, and 166 +/- 17 mu mol kg(-1) during Heinrich ice rafting events H6, H4, and H1. Importantly, at intermediate depth core ODP Site 1055, bottom water [O-2] was lower during parts of Marine Isotope Stage 4 and millennial cool events, with the lowest values of 179 and 194 mu mol kg(-1) recorded during millennial cool event C21 and a cool event following Dansgaard-Oeschger event 19. Our reconstructions agree with previous model simulations suggesting that glacial cold events may be associated with lower seawater [O-2] across the North Atlantic below similar to 1 km (Schmittner et al., 2007), although in our reconstructions the changes are less dramatic. The decreases in bottom water [O-2] during North Atlantic Heinrich events and earlier cold events at the two sites can be linked to water mass changes in relation to ocean circulation changes and possibly productivity changes. At the intermediate depth site a possible strong North Atlantic Intermediate Water cell would preclude water mass changes as a cause for decreased bottom water [O-2]. Instead, we propose that the lower bottom [O-2] there can be linked to productivity changes through increased export of organic material from the surface ocean and its subsequent remineralization in the water column and the sediment.
PY 2016
SO Biogeosciences
SN 1726-4170
PU Copernicus Gesellschaft Mbh
VL 13
IS 1
UT 000369524000014
BP 211
EP 221
DI 10.5194/bg-13-211-2016
ID 46416
ER

EF