Reconstructing the Nd oceanic cycle using a coupled dynamical - biogeochemical model

ISI Document Delivery No.: 536QY Times Cited: 37 Cited Reference Count: 73 Cited References: Amakawa H, 2004, GEOCHIM COSMOCHIM AC, V68, P715, DOI 10.1016/S0016-7037(03)00501-5 ANDERSON RF, 1990, EARTH PLANET SC LETT, V96, P287, DOI 10.1016/0012-821X(90)90008-L Arsouze T, 2007, CHEM GEOL, V239, P165, DOI 10.1016/j.chemgeo.2006.12.006 Arsouze T, 2008, CLIM PAST, V4, P191 Aumont O, 2003, GLOBAL BIOGEOCHEM CY, V17, DOI 10.1029/2001GB001745 Aumont O, 2006, GLOBAL BIOGEOCHEM CY, V20, DOI 10.1029/2005GB002591 BACON MP, 1982, J GEOPHYS RES-OC ATM, V87, P2045, DOI 10.1029/JC087iC03p02045 Bayon G, 2004, EARTH PLANET SC LETT, V224, P477, DOI 10.1016/j.epsl.2004.05.033 BERTRAM CJ, 1993, GEOCHIM COSMOCHIM AC, V57, P1957, DOI 10.1016/0016-7037(93)90087-D BLANKE B, 1993, J PHYS OCEANOGR, V23, P1363, DOI 10.1175/1520-0485(1993)023<1363:VOTTAO>2.0.CO;2 Boillot G., 1998, DECHIRURE CONTINENTA Broecker W. S., 1982, TRACERS SEA Dahlqvist R, 2005, EARTH PLANET SC LETT, V233, P9, DOI 10.1016/j.epsl.2005.02.021 Doney SC, 2004, GLOBAL BIOGEOCHEM CY, V18, DOI 10.1029/2003GB002150 DUCE R A, 1991, Global Biogeochemical Cycles, V5, P193, DOI 10.1029/91GB01778 Dutay JC, 2002, OCEAN MODEL, V4, P89, DOI 10.1016/S1463-5003(01)00013-0 Dutay JC, 2004, J MARINE SYST, V48, P15, DOI 10.1016/j.jmarsys.2003.05.010 Dutay JC, 2009, GEOCHEM GEOPHY GEOSY, V10, DOI 10.1029/2008GC002291 ELDERFIELD H, 1988, PHILOS T R SOC A, V325, P105, DOI 10.1098/rsta.1988.0046 ELDERFIELD H, 1990, GEOCHIM COSMOCHIM AC, V54, P971, DOI 10.1016/0016-7037(90)90432-K Fichefet T, 1997, J GEOPHYS RES-OCEANS, V102, P12609, DOI 10.1029/97JC00480 Gehlen M, 2006, BIOGEOSCIENCES, V3, P521 GENT PR, 1990, J PHYS OCEANOGR, V20, P150, DOI 10.1175/1520-0485(1990)020<0150:IMIOCM>2.0.CO;2 *GEOTRACES, 2005, INT STUD MAR BIOG CY, P12807 Goldstein S. L., 2003, TREATISE GEOCHEMISTR GOLDSTEIN SJ, 1987, CHEM GEOL, V66, P245, DOI 10.1016/0168-9622(87)90045-5 GOLDSTEIN SL, 1984, EARTH PLANET SC LETT, V70, P221, DOI 10.1016/0012-821X(84)90007-4 GREAVES MJ, 1994, MAR CHEM, V46, P255, DOI 10.1016/0304-4203(94)90081-7 GROUSSET FE, 1988, EARTH PLANET SC LETT, V87, P367, DOI 10.1016/0012-821X(88)90001-5 Grousset FE, 1998, QUATERNARY SCI REV, V17, P395, DOI 10.1016/S0277-3791(97)00048-6 Gutjahr M, 2008, EARTH PLANET SC LETT, V266, P61, DOI 10.1016/j.epsl.2007.10.037 Henderson GM, 1999, DEEP-SEA RES PT I, V46, P1861, DOI 10.1016/S0967-0637(99)00030-8 JEANDEL C, 1993, EARTH PLANET SC LETT, V117, P581, DOI 10.1016/0012-821X(93)90104-H JEANDEL C, 1995, GEOCHIM COSMOCHIM AC, V59, P535, DOI 10.1016/0016-7037(94)00367-U Jeandel C, 2007, CHEM GEOL, V239, P156, DOI 10.1016/j.chemgeo.2006.11.013 Jeandel C, 1998, GEOCHIM COSMOCHIM AC, V62, P2597, DOI 10.1016/S0016-7037(98)00169-0 Johannesson KH, 2007, EARTH PLANET SC LETT, V253, P129, DOI 10.1016/j.epsl.2006.10.021 JONES K, 2008, EARTH PLANET SC LETT, V202, P610 Khatiwala S, 2005, OCEAN MODEL, V9, P51, DOI 10.1016/j.ocemod.2004.04.002 Kriest I, 2002, DEEP-SEA RES PT I, V49, P2133, DOI 10.1016/S0967-0637(02)00127-9 Lacan F, 2001, EARTH PLANET SC LETT, V186, P497, DOI 10.1016/S0012-821X(01)00263-1 Lacan F, 2004, GEOPHYS RES LETT, V31, DOI 10.1029/2004GL019747 Lacan F, 2005, EARTH PLANET SC LETT, V232, P245, DOI 10.1016/j.epsl.2005.01.004 MADEC G, 2006, NEMO REFERENCE MANUA, P27 MILLIMAN J. D., 1992, J GEOL, V100, P325 Monod J, 1942, RECHERCHES CROISSANC Nozaki Y., 1995, BIOGEOCHEMICAL PROCE, P171 Nozaki Y, 2003, EARTH PLANET SC LETT, V205, P155, DOI 10.1016/S0012-821X(02)01027-0 NOZAKI Y, 1981, EARTH PLANET SC LETT, V54, P203, DOI 10.1016/0012-821X(81)90004-2 Oka A, 2008, GLOBAL BIOGEOCHEM CY, V22, DOI 10.1029/2007GB003067 PIEPGRAS DJ, 1983, J GEOPHYS RES-OC ATM, V88, P5997, DOI 10.1029/JC088iC10p05997 PIEPGRAS DJ, 1987, GEOCHIM COSMOCHIM AC, V51, P1257, DOI 10.1016/0016-7037(87)90217-1 PIEPGRAS DJ, 1979, EARTH PLANET SC LETT, V45, P223, DOI 10.1016/0012-821X(79)90125-0 PIEPGRAS DJ, 1982, SCIENCE, V217, P207, DOI 10.1126/science.217.4556.207 PIEPGRAS DJ, 1980, EARTH PLANET SC LETT, V50, P128, DOI 10.1016/0012-821X(80)90124-7 Piotrowski AM, 2004, EARTH PLANET SC LETT, V225, P205, DOI 10.1016/j.epsl.2004.06.002 Rickli J, 2009, EARTH PLANET SC LETT, V280, P118, DOI 10.1016/j.epsl.2009.01.026 Rutberg RL, 2000, NATURE, V405, P935 SHIMIZU H, 1994, GEOCHIM COSMOCHIM AC, V58, P323, DOI 10.1016/0016-7037(94)90467-7 SHOLKOVITZ ER, 1993, GEOCHIM COSMOCHIM AC, V57, P2181, DOI 10.1016/0016-7037(93)90559-F SHOLKOVITZ ER, 1994, GEOCHIM COSMOCHIM AC, V58, P1567, DOI 10.1016/0016-7037(94)90559-2 Siddall M, 2008, EARTH PLANET SC LETT, V274, P448, DOI 10.1016/j.epsl.2008.07.044 Siddall M, 2005, EARTH PLANET SC LETT, V237, P135, DOI 10.1016/j.epsl.2005.05.031 STORDAL MC, 1986, EARTH PLANET SC LETT, V77, P259, DOI 10.1016/0012-821X(86)90138-X Tachikawa K, 1999, EARTH PLANET SC LETT, V170, P433, DOI 10.1016/S0012-821X(99)00127-2 Tachikawa K, 1997, DEEP-SEA RES PT I, V44, P1769, DOI 10.1016/S0967-0637(97)00057-5 Tachikawa K, 2003, J GEOPHYS RES-OCEANS, V108, DOI 10.1029/1999JC000285 TEGEN I, 1995, J GEOPHYS RES-ATMOS, V100, P18707, DOI 10.1029/95JD02051 Timmermann R, 2005, OCEAN MODEL, V8, P175, DOI 10.1016/j.ocemod.2003.12.009 Van De Flierdt T, 2004, GEOCHIM COSMOCHIM AC, V68, P3827 von Blanckenburg F, 1996, EARTH PLANET SC LETT, V141, P213, DOI 10.1016/0012-821X(96)00059-3 von Blanckenburg F, 1999, SCIENCE, V286, P1862 Zhang Y, 2008, DEEP-SEA RES PT II, V55, P638, DOI 10.1016/j.dsr2.2007.12.029 Arsouze, T. Dutay, J. -C. Lacan, F. Jeandel, C. Lacan, Francois/B-8032-2009 38 COPERNICUS GESELLSCHAFT MBH GOTTINGEN BIOGEOSCIENCESThe decoupled behaviour observed between Nd isotopic composition (Nd IC, also referred as epsilon(Nd)) and Nd concentration cycles has led to the notion of a 'Nd paradox'. While epsilon(Nd) behaves in a quasi-conservative way in the open ocean, leading to its broad use as a water-mass tracer, Nd concentration displays vertical profiles that increase with depth, together with a deep-water enrichment along the global thermohaline circulation. This non-conservative behaviour is typical of nutrients affected by scavenging in surface waters and remineralisation at depth. In addition, recent studies suggest the only way to reconcile both concentration and Nd IC oceanic budgets, is to invoke a 'Boundary Exchange' process (BE, defined as the co-occurrence of transfer of elements from the margin to the sea with removal of elements from the sea by Boundary Scavenging) as a source-sink term. However, these studies do not simulate the input/output fluxes of Nd to the ocean, and therefore prevents from crucial information that limits our understanding of Nd decoupling. To investigate this paradox on a global scale, this study uses for the first time a fully prognostic coupled dynamical/biogeochemical model with an explicit representation of Nd sources and sinks to simulate the Nd oceanic cycle. Sources considered include dissolved river fluxes, atmospheric dusts and margin sediment re-dissolution. Sinks are scavenging by settling particles. This model simulates the global features of the Nd oceanic cycle well, and produces a realistic distribution of Nd concentration (correct order of magnitude, increase with depth and along the conveyor belt, 65% of the simulated values fit in the +/- 10 pmol/kg envelop when compared to the data) and isotopic composition (inter-basin gradient, characterization of the main water-masses, more than 70% of the simulated values fit in the +/- 3 epsilon(Nd) envelop when compared to the data), though a slight overestimation of Nd concentrations in the deep Pacific Ocean may reveal an underestimation of the particle fields by the biogeochemical model. Our results indicate 1) vertical cycling (scavenging/remineralisation) is absolutely necessary to simulate both concentration and epsilon(Nd), and 2) BE is the dominant Nd source to the ocean. The estimated BE flux (1.1x10(10) g(Nd)/yr) is much higher than both dissolved river discharge (2.6x10(8) g(Nd)/yr) and atmospheric inputs (1.0x10(8) g(Nd)/yr) that both play negligible role in the water column but are necessary to reconcile Nd IC in surface and subsurface waters. This leads to a new calculated residence time of 360 yrs for Nd in the ocean. The BE flux requires the dissolution of 3 to 5% of the annual flux of continental weathering deposited via the solid river discharge to the continental margin