Neodymium isotopes in seawater from the Barents Sea and Fram Strait Arctic-Atlantic gateways.

Andersson, Per S., Porcelli, Don, Frank, Martin , Björk, Göran, Dahlqvist, Ralf and Gustavsson, Orjan (2008) Neodymium isotopes in seawater from the Barents Sea and Fram Strait Arctic-Atlantic gateways. Geochimica et Cosmochimica Acta, 72 . pp. 2854-2867. DOI 10.1016/j.gca.2008.04.008.

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Abstract

The neodymium concentration, CNd, and isotopic composition, eNd, in seawater have been determined in the water column
at five sites in the Barents Sea–Fram Strait area where most of the water exchange between the Arctic Ocean and the North
Atlantic takes place. In the main Arctic Ocean inflow branch across the Barents Sea the concentration and isotopic composition
(CNd = 15.5 pmol/kg and eNd = -10.8) are similar to those reported for the northeastern Nordic Seas, which is consistent
with this region being a source area for the Arctic inflow. Due to the addition of Nd from Svalbard shelf sediments, the
CNd in the surface waters above 150 m, in the Fram Strait inflow branch is higher by a factor of 2 and the eNd is shifted to
lower values (-11.8).
In the stratified Nansen Basin, where cold low salinity water overlies warmer Atlantic water the CNd and eNd do not vary
with the vertical temperature–salinity structure but are essentially constant and similar to those of the Atlantic inflow
throughout the entire water column, down to 3700 m depth, which indicates that the Nd is to a large extent of Atlantic origin.
Compared to the Atlantic inflow water, the Nd in the major Arctic Ocean outflow, the Fram Strait, show higher CNd in the
surface waters above 150 m, and a higher eNd (-9.8) throughout the entire water column down to 1300 m depth. Sources for
the more radiogenic Nd isotopic composition in deep water of the Fram Strait outflow most likely involve boundary exchange
with sediments on the shelf and slope as the water passes along the Canadian archipelago. River water is a possible source in
the surface water but it also seems likely that Pacific water Nd, modified by interactions on the shelf, is an important component
in the Fram Strait surface outflow. Changes in the relative proportions of inflow of river water and flow of Pacific
water through the Arctic Ocean could thus influence the isotopic composition of Nd in the North Atlantic.

Document Type: Article
Keywords: Neodymium isotopes, seawater, Barents Sea, Fram Strait
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.gca.2008.04.008
ISSN: 0016-7037
Projects: Future Ocean
Date Deposited: 03 Dec 2008 16:52
Last Modified: 01 Nov 2017 14:37
URI: http://oceanrep.geomar.de/id/eprint/4845

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