The Significance of the River Input of Chemical Elements to the Ocean

Martin, Jean‐Marie; Whitfield, M.

doi:10.1007/978-1-4757-6864-0_16

Cited by 293 publications

(173 citation statements)

References 32 publications

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“…The range of concentrations of dissolved Fe, Al, and Mn span, but are generally higher than, the world average values (Martin and Whitfield 1983). There is a general inverse relationship between the abundance of major and minor cations, such that rivers draining limestone-rich regions have higher concentrations of Na, K, Ca, and Mg but lower concentrations of Fe, Al, and Mn.…”

Section: Resultsmentioning

confidence: 92%

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Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

Hill

Aplin

2001

Limnology & Oceanography

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We have used cross flow filtration (CFF) to determine the pools of fine particulate (0.1-0.45 m), colloidal (1,000 Dalton to 0.1 m), and dissolved (Ͻ1,000 Dalton) metals in seven rivers that are all relatively rich in organic matter but have differing pH, alkalinity, and ionic strength. The metal content of Ͻ0.45-m filtered river water primarily reflects a mixing of two metal pools with differing elemental compositions: a truly dissolved pool and a colloidal pool. Fine particulate metals contribute Ͻ10% of the total metal load of Ͻ0.45-m filtered water. Colloidal metals generally comprise at least the following percentages of the metal load of Ͻ0.45-m filtered water: Ͼ50% of Fe, Al, and trace metals; 30% Mn, 25% Ca and Mg; 15% Na and K; and a few percent Si. We believe that these figures are minima because recovery experiments with the CFF apparatus suggest that whilst recoveries of pure metal salt solutions are close to 100%, only 70% of particle-reactive metals are recovered from metal salt solutions spiked with humic acid. We propose that the metal composition of riverine colloids is primarily controlled by element mobility during weathering. In organic-rich soils with low acid-neutralizing capacity, low pH solutions drive the dissolution of aluminosilicates and oxides. Uptake of Al, Fe, and trace metals onto colloidal organic matter helps to maintain low activities of dissolved metals and enhances mineral dissolution. Colloids derived from these soils are thus enriched in Al, Fe, Mn, and trace metals, resulting in high concentrations of these elements in Ͻ0.45-m filtered water. In carbonate-rich soils, rapid neutralization of rainwater by carbonate minerals restricts the mobilization of aluminosilicates and oxides. Compared to colloids from rivers draining silicate terrains, colloids in carbonate-rich systems have higher total loadings of metals, are enriched in alkali and alkaline earth metals, but are depleted in Al, Fe, and trace metals.Quantifying weathering processes and the subsequent transport of elements to the ocean is a fundamental aim of geochemistry. Although the abundance of dissolved elements has been commonly and pragmatically quantified by filtering water at 0.45 m, it is well known that sub-0.1-m colloidal phases, such as organic matter and oxides, interact strongly with dissolved metals (for reviews see Buffle 1988;Stumm 1992Stumm , 1993Gustafsson and Gschwend 1997). Several previous studies suggest that colloids can be important metal carriers in freshwater (e.g., Giesy and Briese 1977;Reuter and Perdue 1977;Hoffmann et al. 1981;Salbu et al. 1985;Tanizaki et al. 1992;Dai and Martin 1995;Ross and Sherrell 1999), and it is likely that the loss of metals from estuarine water is related to the coagulation of colloids (Sholkovitz 1976;Boyle et al. 1977).This paper reports the results of a study aimed at determining the importance of colloids as metal carriers in a series of rivers of widely varying pH and ionic strength. Cross flow filtration (CFF) is developed as a method of fraction-1...

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Section: Resultsmentioning

confidence: 92%

“…General geochemistry-The major ion composition of these rivers varies considerably and spans the global average river composition (Table 1; Martin and Meybeck 1979;Martin and Whitfield 1983). Based largely on the geology of their drainage basins, the rivers can be divided into three main categories.…”

Section: Resultsmentioning

confidence: 99%

Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

Hill

Aplin

2001

Limnology & Oceanography

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“…Annual particulate fluxes of Sc and Th observed with the sediment trap at 1 km depth were 43 and 17 mg/m 2 / year, respectively. Averaged Sc and Th concentrations in seawater (0-1000 m) were 10 pmol/kg and 0.05 pmol/kg (Zhang et al, 1994;Chen et al, 1986), and residence time were estimated to 8000 years for Sc and 15 years for Th (Martin and Whitfield, 1983). The removal fluxes of Sc and Th from the water column at 1 km depth are calculated to 0.058 and 0.797 mg/m 2 /year, respectively.…”

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

confidence: 97%

“…It has been pointed out that iron, phosphorus and some elements in aluminosilicates enhance the biological activity in the surface ocean (Martin and Whitfield, 1983;Harrison et al, 1999). Supply and transport mechanisms of aluminosilicates in the water column become important in order to investigate various biogeochemical processes.…”

Section: Introductionmentioning

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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“…It has to be also kept in mind that natural processes also modify and redistribute anthropogenic contamination between solid and water phases. According to Martin and Whitfield [1] the accumulation of metal contaminants in coastal sediments gives a reliable picture of the spatial and temporal pollution history.…”

Section: Introductionmentioning

confidence: 99%

An advanced multivariate statistical approach to study coastal sediment data

et al. 2006

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Abstract:The present paper deals with the application of classical and fuzzy principal components analysis to a large data set from coastal sediment analysis. Altogether 126 sampling sites from the Atlantic Coast of the USA are considered and at each site 16 chemical parameters are measured. It is found that four latent factors are responsible for the data structure ("natural", "anthropogenic", "bioorganic", and "organic anthropogenic"). Additionally, estimating the scatter plots for factor scores revealed the similarity between the sampling sites. Geographical and urban factors are found to contribute to the sediment chemical composition. It is shown that the use of fuzzy PCA helps for better data interpretation especially in case of outliers.

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The Significance of the River Input of Chemical Elements to the Ocean

Cited by 293 publications

References 32 publications

Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

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

An advanced multivariate statistical approach to study coastal sediment data

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