Influence of organic matter on the adsorption of 210Pb, 210Po and 7Be and their fractionation on nanoparticles in seawater

Yang, Weifeng; Guo, Laodong; Chuang, Chia‐Ying; Santschi, Peter H.; Schumann, D.; Ayranov, M.

doi:10.1016/j.epsl.2015.05.007

Cited by 37 publications

(25 citation statements)

References 86 publications

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“…In addition, a few studies on hydrothermal plumes indicate that hydrothermal particles favor the interactions between Fe and dissolved organic matter [ Toner et al ., ], and this interaction increases the delivery of POC from the hydrothermal plume to the sediments [ German et al ., ]. Controlled experiments also reveal the adsorption of dissolved organic carbon (DOC) onto Fe/Mn (hydr)oxides [ Yang et al ., ]. A series of studies suggests that the DOC in seawater, including marine exopolymeric substances [ Quiroz et al ., ; Zhang et al ., ], acid polysaccharide [ Quigley et al ., ], proteins, total carbohydrates, and uronic acids [ Chuang et al ., ], has numerous binding ligands which can combine with 234 Th.…”

Section: Discussionmentioning

confidence: 98%

Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Yang

Zhang²,

Chen

et al. 2016

Geochem. Geophys. Geosyst.

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Particle dynamics in hydrothermal plumes are crucial to understanding the cycling of carbon and trace elements in the global oceans, but this subject area has been poorly studied. We investigated radioactive 234Th in a hydrothermal plume of a recently discovered vent over the Southwest Indian Ridge (SWIR). Above the plume, total 234Th was in equilibrium with 238U, showing the typical characteristic of general deep water. However, there was a 234Th deficit within the plume, with 234Th/238U ratios in the 0.77–0.91 range. Particulate 234Th accounted for ∼10% of the total 234Th, contrasting with 4% in the overlying water. On average, the scavenging and removal rates of 234Th were 17.5 ± 2.5 dpm m−3 d−1 and 11.8 ± 2.5 dpm m−3 d−1. The residence time of dissolved 234Th (avg. 108 ± 8 d) was much higher than particulate 234Th (avg. 19 ± 1 d), indicating that scavenging of 234Th from dissolved to particulate phase dominated its residence time scale. Particulate organic carbon (POC) increased 15% within the plume, compared with the overlying water. Combining the removal of 234Th and the ratio of POC to particulate 234Th, the POC removal flux was 9.3 ± 0.6 mmol m−2 d−1. Similarly, 2.2 ± 0.6 mmol m−2 of particulate nitrogen (PN) was removed per day from the plume. The magnitude of POC and PN removal implied an important role of the hydrothermal plume in delivering organic matter to the seafloor. This study thus reveals the different particle dynamic characteristics within the hydrothermal plume over the SWIR compared to the ordinary deep oceans.

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Section: Discussionmentioning

confidence: 98%

Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Yang

Zhang²,

Chen

et al. 2016

Geochem. Geophys. Geosyst.

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“…Previous laboratory studies have also suggested that Pb and Th can be strongly adsorbed onto magnetic minerals (e.g., hematite and magnetite; Murphy et al, ; Rajput et al, ). The relationship between excess 210 Pb ( 210 Pb ex ), excess 234 Th ( 234 Th ex ), and the χ ARM /SIRM ratio exhibited no regional differences because 234 Th ex and 210 Pb ex have stronger affinities for lithogenic particles and are less affected by organic matter in comparison to other radionuclides (e.g., 7 Be; Geibert & Usbeck, ; Yang et al, ). However, the relationship between 7 Be and the χ ARM /SIRM ratio differed between the southern and northern regions of the study area (Figure ).…”

Section: Resultsmentioning

confidence: 99%

“…However, the relationship between 7 Be and the χ ARM /SIRM ratio differed between the southern and northern regions of the study area (Figure ). The transfer of atmospheric 7 Be to sediments can be influenced by organic matter or lithogenic particles (Yang et al, ). The sediment in the northern region of the study area is dominated by relatively higher fraction of coarser particles with lower clay fractions (~15%).…”

Section: Resultsmentioning

confidence: 99%

Fingerprinting Sediment Transport in River‐Dominated Margins Using Combined Mineral Magnetic and Radionuclide Methods

et al. 2018

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Both magnetic properties and radionuclides are widely used to trace sediment transport in aquatic environments; however, these methods have not been used in combination. In this study, the East China Sea (ECS), a typical river‐dominated margin, was chosen to demonstrate the advantages of combining these two methods to track sediment movements on a seasonal to annual timescale. The ratios between saturation isothermal remnant magnetization and anhysteretic remnant magnetization (χARM/SIRM) and 7Be/210Pbex activity ratios as well as mass balance of 7Be provide information on the seasonal transport of sediment from the Changjiang Estuary to the neighboring shelf. Both 210Pb budget and SIRM distribution in the inner shelf of the ECS show that a small fraction (at most 14% of annual Changjiang sediment discharge) of particles could be transported offshore. Most of 7Be activities in inner shelf sediments of the ECS were below detection limit due to relatively lower residence times and dilution by the older sediment. The observation that radionuclide activities exhibit a better correlation with χARM/SIRM ratios than with grain size suggests that iron oxides are the primary carriers of 7Be, 210Pb, and 234Th. The absorption of radionuclides onto magnetic minerals further reinforces the reliability of this combined approach in tracing sediment transport. Our study indicates that radionuclides, with different half‐lives, can be utilized for quantifying sediment dynamics, whereas magnetic properties can yield more detailed information on sediment transport directions. The combined analysis of magnetic parameters and radionuclides offers a better understanding of sediment transport in river‐dominated areas.

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“…It is well known that 210 Pb ex is more effectively scavenged by particulate organic matter than fine lithogenic particles (i.e., clay) (cf. Moore and Dymondt 1988;Robbins and Edgington 1975;Oguri et al 2012;Yang et al 2015). In August 2012, Lu et al (2013) recorded an upwelling event east of the sill in the Narrows.…”

Section: Indications Of Riverine Inputs Focusing and Boundary Scavementioning

confidence: 99%

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador

et al. 2017

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Abstract:The sources and distribution of sediment and particulate organic carbon (OC) to Lake Melville, Labrador, were characterized to better understand impacts from climate and hydrological changes to the system. Mass accumulation rates (MARs) across the Lake Melville System (LMS) were established from 15 sediment cores collected in 2013 and 2014 by fitting excess 210 Pb ( 210 Pb ex ) profiles to a two-layer advection-diffusion model. MARs, validated using 137 Cs, varied between 0.04 and 0.41 g cm −2 a −1 , and overall decreased with increasing distance from the Churchill River, which drains into Goose Bay, a western extension of Lake Melville. The Churchill River is the greatest source of sediment to the system, but surprisingly, MARs were greatest in western Lake Melville rather than Goose Bay, reflecting the contribution of fine material carried eastward in the Churchill River plume and inputs from nearby tributaries. A comparison of 137 Cs and 210 Pb ex inventories to expected atmospheric fallout (1.5 and 23.6 disintegrations per minute (dpm) cm −2 , respectively) in sediment across the LMS suggests particles are largely sourced from the watershed. In eastern Lake Melville, elevated 210 Pb ex inventories and marine OC point to particle scavenging of dissolved 210 Pb from inflowing marine water. A transient tracer mixing model was used to determine the depth in each core where >90% of sediment was deposited before and after hydroelectric development at Churchill Falls (1970) and applied to down-core profiles of OC and organic carbon isotopes (␦ 13 C org ). We observed a significant increase of terrestrial OC to Lake Melville post 1970, which we interpret as change from climate or hydrology of the Churchill River.Résumé : Les sources et la répartition des sédiments et du carbone organique (CO) particulaire du lac Melville, au Labrador, ont été caractérisées pour mieux comprendre les impacts des changements climatiques et hydrologiques sur ce système. Les taux d'accumulation massique (TAM) à l'échelle du système du lac Melville (SLM) ont d'abord été établis à la lumière de 15 carottes de sédiments prélevées en 2013 et 2014, en calant les profils de 210 Pb excédentaire ( 210 Pb ex ) sur un modèle de advection-diffusion à deux couches. Les TAM, validés en utilisant le 137 Cs, vont de 0,04 à 0,41 g cm −2 a −1 , mais diminuent en s'éloignant de la rivière Churchill, qui se déverse dans la baie Goose, un prolongement vers l'ouest du lac Melville et la plus importante source de sédiments entrant dans le système. Étonnement, les TAM sont les plus élevés dans la partie occidentale du lac Melville, reflétant les apports de matériaux fins transportés vers l'est dans le panache de la rivière Churchill et de plus petits affluents situés à proximité. Une comparaison des inventaires de 137 Cs et de 210 Pb ex aux retombées atmosphériques attendues (1,5 et 23,6 désin-tégrations par minute (dpm) cm −2 , respectivement) dans les sédiments à l'échelle du SLM porte à croire que les particules proviennent en majeure partie du ba...

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Influence of organic matter on the adsorption of 210Pb, 210Po and 7Be and their fractionation on nanoparticles in seawater

Cited by 37 publications

References 86 publications

Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Fingerprinting Sediment Transport in River‐Dominated Margins Using Combined Mineral Magnetic and Radionuclide Methods

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador

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Influence of organic matter on the adsorption of 210Pb, 210Po and 7Be and their fractionation on nanoparticles in seawater

Cited by 37 publications

References 86 publications

Unusually low234Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Unusually low234Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Fingerprinting Sediment Transport in River‐Dominated Margins Using Combined Mineral Magnetic and Radionuclide Methods

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:210Pb,137Cs, and δ13C records from Lake Melville, Labrador

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Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Unusually low²³⁴Th in a hydrothermal effluent plume over the Southwest Indian Ridge

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador