Distribution of rare earth elements and neodymium isotopes in suspended particles of the tropical Atlantic Ocean (EUMELI site)

Tachikawa, Kazuyo; Jeandel, Catherine; Vangriesheim, Annick; Dupré, Bernard

doi:10.1016/s0967-0637(98)00089-2

Cited by 112 publications

(82 citation statements)

References 26 publications

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“…Such contention has been documented by the previous investigators (e.g., Byrne and Kim, 1990;Elderfield et al, 1990;Sholkovitz et al, 1994;Byrne and Sholkovitz, 1996;Sholkovitz, 1995;Fu et al, 1997;Tachikawa et al, 1999;Kuss et al, 2001;Arraes-Mescoff et al, 2001). However, silicic rock normalized REE patterns for the 3-0.45 µm size fractions are not so much enriched in the light REE (Fig.…”

Section: Comparison Between 3 µM and 045 µM Filtered Samplessupporting

confidence: 70%

Rare earth element abundances in some seawaters and related river waters from the Osaka Bay area, Japan: Significance of anthropogenic Gd

Ogata

Terakado

2006

Geochem. J.

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Some major and trace elements in seawaters and related river waters from the Osaka Bay area, Japan were analyzed in order to examine rare earth element (REE) behaviors, especially the relationship between anthropogenic gadolinium (Gd) and nutrient concentrations. The local silicic rock normalized REE patterns for the seawaters show features of light REE depletion, negative Ce anomaly, and very small Eu anomaly. Moreover, some samples have obvious positive Gd anomalies due to contamination of Magnetic Resonance Imaging (MRI) contrast agents in medical use. We calculated the anthropogenic Gd concentrations by subtracting the assumed natural Gd concentration from the measured one. The anthropogenic or excess Gd concentrations of the seawater samples are well correlated with nutrient concentrations (NH 4 -N, NO 2 -N, NO 3 -N, PO 4 -P). Because both anthropogenic Gd and nutrients are abundant in sewage treatment plant (STP) effluents and much less abundant in non-contaminated river and seawaters, the observed trends can be explained by dilution of STP effluents with non-contaminated river and seawaters. It was found that the nutrient concentrations for a hypothetical STP effluent calculated by using these correlation lines are consistent with the average nutrient contents for the STP effluents in the study area. Moreover, we made a rough estimation of Gd budget in Osaka Bay. The estimated amount of the Gd MRI contrast agents consumed in the area seems to be consistent with the excess Gd concentrations of river and STP waters. The Gd observations in this study suggest that the Gd anomaly data can be used as a geochemical tracer of wastewater component in urban areas.

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Section: Comparison Between 3 µM and 045 µM Filtered Samplessupporting

confidence: 70%

Rare earth element abundances in some seawaters and related river waters from the Osaka Bay area, Japan: Significance of anthropogenic Gd

Ogata

Terakado

2006

Geochem. J.

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“…Secondly, the Nd isotopic compositions of surface waters appear to be more easily changed by dust input (Bayon et al, 2002b;Tachikawa et al, 1999b) than those of bottom waters (Jones et al, 1994). Models of regional dustiness also suggest greater dust input to the Indian Ocean during the last glacial (Mahowald et al, 2006), which is supported by the higher aluminium content of glacial detrital sediments from Somali margin cores, interpreted as a proxy of dustiness indicating higher dust contact during glacials than interglacials (Ivanochko et al, 2005).…”

Section: Proxy Records Of Deep Indian Ocean Paleocirculationmentioning

confidence: 99%

Indian Ocean circulation and productivity during the last glacial cycle

Piotrowski

Banakar

Scrivner

et al. 2009

Earth and Planetary Science Letters

102

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The Indian Ocean is an important part of the global thermohaline circulation system, receiving deep waters sourced from the Southern Ocean and being the location of upwelling and surface-ocean current flow, which returns warm and salty waters to the Atlantic. It is also an ideal location to reconstruct the link between thermohaline circulation and deep-water nutrient contents. No mixing occurs between major deep-water masses along flow paths within the Indian Ocean, so changes in water-mass provenance reflect changes in deep-ocean circulation while nutrient contents reflect addition and dissolution of organic matter. We present neodymium (Nd) and carbon (C) isotope records, proxies of water-mass provenance and nutrient contents, respectively, from an equatorial Indian Ocean core (SK129−CR2) spanning the last 150 kyr. The Nd isotope record shows that an increased proportion of North Atlantic Deep Water (NADW) reached the Indian Ocean during interglacials (marine isotope stages, MIS 1 and 5), and a reduced proportion during glacials (MIS 2, 4, and 6), and also that changes occurred during

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“…Elemental composition of particulate materials could be changed by adsorption/desorption of chemical elements and/or biological uptake of dissolved components in the water column (e.g., Tachikawa et al, 1999). In the marine environment, La is known as the most reactive element of the trivalent REEs (Cantrell and Byrne, 1987;Sholkovitz et al, 1994;Lerche and Nozaki, 1998).…”

Section: Sc Th and Rees As Indicators Of The Origin Of Aluminosilicatesmentioning

confidence: 99%

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

2004

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In order to understand the origins and transport processes of lithogenic aluminosilicate in the western North Pacific, time-series sediment traps were deployed at Stn. KNOT at 44∞N 155∞E (water depth: 5320 m). Annual mean content of aluminum (Al) which is a proxy of lithogenic material in settling particles was 0.38% at 1 km depth, 0.78% at 3 km depth and 1.14% at 5 km depth, respectively. Mass fluxes were corrected by 230 Th and 231 Pa activities in particles and seawater. Annual mean corrected Al fluxes at 1, 3 and 5 km depths were calculated to 0.45, 0.46 and 0.33 g/m 2 /year, respectively. Lanthanum/ytterbium (La/Yb) and thorium/scandium (Th/Sc) ratios were used as proxies for estimating the origin of lithogenic aluminosilicate in settling particles. Both La/Yb and Th/Sc ratios in settling particles increased with depth, and the seasonal variation was the smallest at 5 km depth. It was considered that variations of La/Yb and Th/Sc ratios in settling particles reflected the change of source material of lithogenic aluminosilicates. Origins of lithogenic materials in the settling particles were summarized using two end-members, loess from central Asian continent (AL) and basalts from the Kurile-Kamchatka Islands (KK). Contributions of end-members in settling particles were estimated from the La/Yb and Th/Sc ratios. The contribution of KK particles in lithogenic materials was calculated to be 84% at 1 km depth, and 61% at 3 and 5 km depths, respectively. Although the KK material was the dominant constituent of the terrigenous component in settling particles at Stn. KNOT, the KK flux decreased with depth. On the other hand, the AL flux increased with depth and the significant increase of the AL flux was presumably due to the lateral import of AL particles to the deep layer at Stn. KNOT. From these results we conclude that the distribution of lithogenic materials recorded in sediments in the western North Pacific are influenced by the northward transport of AL within the deep layer.

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Distribution of rare earth elements and neodymium isotopes in suspended particles of the tropical Atlantic Ocean (EUMELI site)

Cited by 112 publications

References 26 publications

Rare earth element abundances in some seawaters and related river waters from the Osaka Bay area, Japan: Significance of anthropogenic Gd

Rare earth element abundances in some seawaters and related river waters from the Osaka Bay area, Japan: Significance of anthropogenic Gd

Indian Ocean circulation and productivity during the last glacial cycle

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

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