FN Archimer Export Format
PT J
TI Nutrient conditions in the subpolar North Atlantic during the last glacial period reconstructed from foraminifera-bound nitrogen isotopes
BT 
AF STRAUB, M.
   TREMBLAY, M. M.
   SIGMAN, D. M.
   STUDER, A. S.
   REN, H.
   TOGGWEILER, J. R.
   HAUG, G. H.
AS 1:1;2:2;3:3;4:1;5:4;6:5;7:1;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Geological Institute, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland.
   Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, California, USA
   Department of Geosciences, Princeton University, Princeton, New Jersey, USA.
   Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA.
   Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, New Jersey, USA
C2 ETH ZURICH, SWITZERLAND
   UNIV CALIF BERKELEY, USA
   UNIV PRINCETON, USA
   UNIV COLUMBIA, USA
   NOAA, USA
IF 3.918
TC 17
UR https://archimer.ifremer.fr/doc/00262/37308/35721.pdf
LA English
DT Article
CR IMAGES 1-MD101
   MD 123 / GEOSCIENCES 1
BO Marion Dufresne
AB Surface nitrate concentration is a potentially useful diagnostic in reconstructing the past circulation of high-latitude North Atlantic waters. Moreover, nutrient consumption in the North Atlantic surface impacts the atmospheric concentration of carbon dioxide. To reconstruct nutrient conditions in the subpolar North Atlantic region during the last ice age, a record of foraminifera-bound delta N-15 was measured in Neogloboquadrina pachyderma (sin.) from core V28-73 south of Iceland (57.2 degrees N, 20.9 degrees W). Foraminifera-bound delta N-15 is up to 2 parts per thousand lower during the last ice age than during the Holocene, suggesting as much as similar to 25% less complete nitrate consumption during the former. This is consistent with stronger light limitation associated with a deeper summer surface mixed layer, perhaps related to the formation of Glacial North Atlantic Intermediate Water previously suggested to have occurred near the core site. However, three single-point maxima in delta N-15 in the glacial section and the sharp deglacial delta N-15 rise coincide with Heinrich event layers. This suggests that increased water column stratification during Heinrich events, presumably due to surface freshening, reduced the nutrient supply from below and led to nearly complete nitrate consumption in the summertime mixed layer. The Heinrich layers in V28-73 are not accompanied by delta O-18 minima in either N. pachyderma (sin.) or Globigerinoides bulloides, which we tentatively attribute to extreme mixed-layer shoaling. The reconstructed subpolar North Atlantic upper water column changes-both glacial/interglacial and millennial-are inverse to those inferred for the Antarctic.
PY 2013
SO Paleoceanography
SN 0883-8305
PU American Geophysical Union
VL 28
IS 1
UT 000317838200008
BP 79
EP 90
DI 10.1002/palo.20013
ID 37308
ER

EF