Grain size, La/Yb and Th/Sc of settling particles in the western North Pacific: Evidence for lateral transport of small Asian loess

Maeda, Nobuhiro; Noriki, Shinichiro; Narita, Hisashi

doi:10.1007/s10872-007-0068-8

Cited by 8 publications

(5 citation statements)

References 35 publications

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“…Finally, a comparison of lithogenic and biogenic fluxes in other regions, at similar sampling depths, such as in the Panama Basin (Honjo et al 1982) and the NW Pacific (Maeda et al 2007), showed much higher values (11 and 12 mg m -2 day -1 , respectively) than those observed here in the Canary Basin, but the lithogenic/ (lithogenics+biogenic) ratio was similar to that of these studies (0.1-0.4). This generally small range could be a consequence of the well-known micronutrient effect (i.e.…”

Section: Fluxes and Their Interrelationshipssupporting

confidence: 87%

“…This finding suggests that in this oceanic region, as expected, the inputs of lithogenic fluxes are restricted to Saharan dust, without any significant effect from fluvial input. According to the data presented by Maeda et al (2007), the ratio for the NW Pacific Ocean was higher (0.6; Table 1), due to the important fluvial contribution to the lithogenic flux in this area. Opal fluxes (diatoms and radiolarian) were not detected by our image processing but the values measured by Neuer et al (2004) in this area and at this depth were low (0.21 mg m --2 day -1 ).…”

Section: Fluxes and Their Interrelationshipsmentioning

confidence: 89%

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Interaction of sinking behaviour of Saharan dust and lithogenic and biogenic fluxes in the Canary Basin

et al. 2019

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Saharan dust events are currently the predominant source of lithogenic particles in the Canary Basin. In order to quantify this input and its relationship with the biogenic fluxes, a sediment trap was deployed in a free-drifting system at 150 m depth, 50 km off the north coast of Gran Canaria (Canary Islands). The mineralogy of the lithogenic particles included illite, calcite, hematite quartz, barite and kaolinite. The biogenic matter was composed of chitin, transparent exopolymer particles, and carbonates from foraminifera and gastropod shells. The average Saharan dust flux over the ocean surface was approximately 5±4 mg m–2 day-1. The lithogenic, carbonate and chitin fluxes were 0.8±0.6, 6.0±7.4 and 154±386 mg m–2 day-1, respectively. A fairly strong Saharan dust event during sampling was observed in the trap, with a delay of three days in the peaks of lithogenic and biogenic fluxes. The theoretical settling velocity of the lithogenic particles associated with Saharan dust events at 150 m depth was vStokes=275 m day-1, and the experimental settling was about 50 m day-1. The associated sinking behaviour of particulate organic carbon and biogenic and lithogenic fluxes observed in this study may contribute to a more realistic prediction of these fluxes in carbon biological pump models.

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Section: Fluxes and Their Interrelationshipssupporting

confidence: 87%

Section: Fluxes and Their Interrelationshipsmentioning

confidence: 89%

Interaction of sinking behaviour of Saharan dust and lithogenic and biogenic fluxes in the Canary Basin

et al. 2019

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“…A major source is volcanic ash from the surrounding Kurile, Aleutian, Kamchatka, Alaska and Japan volcanic arcs (Bailey, 1993;Jones et al, 1994Jones et al, , 2000Maeda et al, 2007;Nakai et al, 1993;Olivarez et al, 1991;Otosaka et al, 2004;Shigemitsu et al, 2007;Weber et al, 1996). Also contributing to the lithogenic fraction are hemipelagic material (Jones et al, 1994(Jones et al, , 2000, ice-rafted debris (IRD;McKelvey et al, 1995;St.…”

Section: Discussionmentioning

confidence: 99%

“…The other dominant lithogenic component in this region is interpreted to represent volcanic input (e.g., Bailey, 1993;Maeda et al, 2007;Nakai et al, 1993;Olivarez et al, 1991;Otosaka et al, 2004;Shigemitsu et al, 2007;Weber et al, 1996). Volcanic ashes from subduction-related volcanic arcs are known to be effectively helium-free in comparison to continental dust (Patterson et al, 1999; Supplementary Information, Section 2.3).…”

Section: He Terr and 232 Th Approachesmentioning

confidence: 99%

Eolian dust input to the Subarctic North Pacific

Serno

Winckler

Anderson

et al. 2014

Earth and Planetary Science Letters

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Eolian dust is a significant source of iron and other nutrients that are essential for the health of marine ecosystems and potentially a controlling factor of the high nutrient-low chlorophyll status of the Subarctic North Pacific. We map the spatial distribution of dust input using three different geochemical tracers of eolian dust, 4 He, 232 Th and rare earth elements, in combination with grain size distribution data, from a set of core-top sediments covering the entire Subarctic North Pacific. Using the suite of geochemical proxies to fingerprint different lithogenic components, we deconvolve eolian dust input from other lithogenic inputs such as volcanic ash, ice-rafted debris, riverine and hemipelagic input. While the open ocean sites far away from the volcanic arcs are dominantly composed of pure eolian dust, lithogenic components other than eolian dust play a more crucial role along the arcs. In sites dominated by dust, eolian dust input appears to be characterized by a nearly uniform grain size mode at ∼4 μm.Applying the 230 Th-normalization technique, our proxies yield a consistent pattern of uniform dust fluxes of 1-2 g/m 2 /yr across the Subarctic North Pacific. Elevated eolian dust fluxes of 2-4 g/m 2 /yr characterize the westernmost region off Japan and the southern Kurile Islands south of 45 • N and west of 165 • E along the main pathway of the westerly winds. The core-top based dust flux reconstruction is consistent with recent estimates based on dissolved thorium isotope concentrations in seawater from the Subarctic North Pacific. The dust flux pattern compares well with state-of-the-art dust model predictions in the western and central Subarctic North Pacific, but we find that dust fluxes are higher than modeled fluxes by 0.5-1 g/m 2 /yr in the northwest, northeast and eastern Subarctic North Pacific. Our results provide an important benchmark for biogeochemical models and a robust approach for downcore studies testing dust-induced iron fertilization of past changes in biological productivity in the Subarctic North Pacific.

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“…The snow samples were put in polyethylene bags and kept at −25°C in a freezer until the experiment. The particle size distribution of the mineral dust in the snow samples was measured by a laser scattering particle size distribution analyzer (LA‐920, Horiba co ltd., Japan) after pretreatment as described by Maeda et al [2007].…”

Section: Methodsmentioning

confidence: 99%

Size dependence of iron solubility of Asian mineral dust particles

Ooki¹,

Nishioka²,

Ono³

et al. 2009

J. Geophys. Res.

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[1] Asian mineral dust was sampled at Hokkaido, northern Japan, in spring 2004 and 2006. Iron solubility of the bulk aerosol, the size-segregated aerosol (0.45 < D < 11 mm), the snow containing a lot of mineral dust, and a simulated Asian dust standard (CJ-2) were measured by an iron dissolution experiment using a newly developed continuous leaching method. The iron solubility of the bulk aerosol samples was 1.2-2.2%. Within the 1.1 < D < 11 mm size range, iron solubility (0.52-8.2%) was higher in the smaller fractions of the size-segregated aerosol samples. We considered that the preferential removal of larger mineral dust particles from the air by snow resulted in the low iron solubility of the snow samples. Iron solubility of mineral dust was relatively lower in the 4.7 < D < 11 mm fraction of the size-segregated aerosol samples (0.52%), in the snow samples (0.20-0.57%), and in the CJ-2 standard (0.33%), which are dominated by large size particles (D > 4.7 mm). We suggest that an iron solubility of around 0.4% is typical for Asian mineral dust of large particles transported to Hokkaido. In the high-nutrient low-chlorophyll region of the western subarctic North Pacific near the Asian continent, where the mineral dust deposition is dominated by large particles, the iron solubility of the mineral dust entering the ocean is around 0.4%.

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Grain size, La/Yb and Th/Sc of settling particles in the western North Pacific: Evidence for lateral transport of small Asian loess

Cited by 8 publications

References 35 publications

Interaction of sinking behaviour of Saharan dust and lithogenic and biogenic fluxes in the Canary Basin

Interaction of sinking behaviour of Saharan dust and lithogenic and biogenic fluxes in the Canary Basin

Eolian dust input to the Subarctic North Pacific

Size dependence of iron solubility of Asian mineral dust particles

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