Behavior of Strontium,Fluorine, and Boron in the Kuban and Don Mouth Areas

The distributions of concentrations of dissolved Sr, Ca, F, and B in the Kuban and Don mouth areas are studied. It is found that the behavior of F and B is conservative, whereas that of Sr and Ca is slightly nonconservative and is associated with the spatial heterogeneity of the structure of the zone where the river and sea waters are mixing (this heteromogeneity can arise because of dissimilar transformation of continental river runoff in different areas of the near-mouth coastal waters). It is shown that the parameters of linear relationships between the concentrations of Sr and Ca and the chlorides content of water differ in accordance with the seasonal variations in the chemical composition of the river and the Sea of Azov waters; for F and B, such regularity is not found.     

Volcanic Ash as a Source of Dissolved Phosphorus in the Ocean

The process of phosphorus migration from volcanic ash and obsidian to seawater was experimentally studied. For obsidian and ash of the Ksudach, Karymskiy, and Eyjafjallajökull volcanoes, the specific mobilization of phosphorus ranges from 0.3 to 5.0 µg P/g with an average value of ～1.5 µg P/g. The maximum dissolved mineral phosphorus input into the ocean as a result of the interaction between pyroclastic material from arc volcanism and seawater is 4500–9000 t/yr, which does not exceed 0.3–0.6% of its input from river runoff.

     

Sorption–Desorption Transformation of the Runoff of Dissolved Microelements at River–Sea Geochemical Barrier (Based on Data of Experimental Laboratory Simulation)

Water Resources - A new method was used for experimental simulation of the sorption–desorption transformation of microelement composition of the adsorbed complex of solid substances of river...     

Fluorine in the Surface Water of Bering Island

Water Resources - First data have been collected to characterize fluorine concentrations in the surface water of Bering Island (the Komandorskie Islands). The average fluorine concentration is 0.23...     

Terrigenous pyroclastic matter as a source of dissolved calcium in the ocean

It has been found experimentally that the intensity of the leaching under the interaction of volcanic ash and seawater decreases as Ca > Mg > Si, and the mobilization of calcium and magnesium is more intense compared to silicon by factors of 30?C70 and 20?C50, respectively. Calcium and magnesium supplied to seawater owing to the halmyrolysis of the terrigenous pyroclastic matter may then interact with the products of organic matter oxidation to fix the free carbon dioxide in the form of autochthonous carbonates. It was shown that the halmyrolysis of terrigenous pyroclastic matter could not provide the complete immobilization of the autochthonous CO₂ produced in the ocean by the oxidation of organic matter. Thus, some other sources exist for the reactive silicates of calcium and magnesium, and these might probably be the silicates of the continental runoff of solid substances.     

Complexing–precipitating geochemical barriers

New types of geochemical barriers on which chemical elements are immobilized as a result of combined complex formation and precipitation of barely soluble mineral phases are examined. A significant concentration of major components (Fe, Al) forming more stable complexes than an immobilized component X in the material is a necessary condition for this type of geochemical barriers. Filtration of the solution through a geochemical barrier is accompanied by substitution of X in the complex with a major component. As a result, the activity of X in the free state increases, and one barely soluble mineral phase or another of the component X precipitates when the state of saturation is achieved.     

Water migration coefficients of chemical elements in the hypergenesis zone

The contents of basic salt components in the continental discharge related to weathering processes were calculated taking into account the atmospheric transfer of soluble salts from the ocean and their supply from anthropogenic sources. Real water migration coefficients characterizing the mobility of chemical elements in the hypergenesis zone were calculated on the basis of these data. It has been shown that the water migration coefficient directly depends on the solubility of basic minerals that are stable in the hypergenesis zone.     

Absorbed complex of riverine solid substances and its role in geochemical balance of the ocean

Data on the composition of the absorbed complex of riverine solid substances and its transformation in marine environments obtained from field observations and experimental investigations are systematized and generalized. Average values of the specific surface of the riverine suspended particulates (~20 m²/g) and the total exchange capacity of solid substances of the continental runoff (~28 mg-equiv/100 g or 280 g-equiv/t of the transported terrigenous material) are determined. It is shown that the composition of the absorbed complex in the riverine suspended particulates, as well as bottom sediments of rivers and inland water bodies differs principally from that of bottom sediments in oceans and seas: Ca dominates in the first case; Na, in the second case. When the riverine terrigenous material enters oceans and seas, the composition of the absorbed complex is subjected to the ion-exchange transformation reflected in the replacement of exchange Ca (~80%) mainly by Na and also by K and Mg of seawater. This process is responsible for the influx of 45.5 Mt/yr of dissolved Ca to ocean and the removal of 37.3, 12.8, and 3.9 Mt/yr of Na, K, and Mg, respectively. The relative transport of Ca, Na, K, and Mg to ocean with the river runoff is +7.5,–12.3,–22.4, and–2.6%, respectively.     

Chemical transformation of the runoff of dissolved matters in the mouth areas of the Onega and Mezen’ rivers

Natural observations were analyzed to study the distribution of dissolved species of major and trace elements in the Onega and Mezen’ mouth areas and the tendencies in the chemical transformations of the is continental runoff in the river mouths of the White Sea drainage system. It is shown that the migration of major ions and dissolved species of Li, Rb, Cs, Sr, B, F and Mo is consistent with a conservative behavior and is controlled by hydrodynamic processes. The amounts of uranium and barium additionally supplying in the Mezen’ mouth exceed those removed with a continental runoff, whereas the Onega, Severnaya Dvina, and other rivers of the White Sea drainage system are characterized by the conservative behavior of uranium, while barium desorption from particulate matter reaches no more than 33% of its content in the riverine waters. The growth of concentrations of these elements in the Mezen’ mouth is caused by the long-term interaction of solid matters of the continental runoff with saline waters in the tide-affected estuary. 28–59, 12–63, 25–67 and 20–63% of concentrations of iron, aluminum, lanthanum, and cerium are removed from the riverine waters in the mouth areas of all studied rivers of the White Sea drainage system mainly owing to the coagulation and flocculation of organic and organomineral colloids. The distribution of dissolved species of mineral phosphorus and silicon in the Mezen’ mouth is presumably controlled by the remineralization of the organic matter in the bottom sediments, which due to the hydrological features of estuary are regularly stirred up and interact with vertically mixing water sequence. Up to 20–46% of dissolved phosphates and 3–22% of silicon are removed from the continental runoff during vegetation period in the mouths of the Onega, Severnaya Dvina, and other rivers of the White Sea drainage system mainly owing to their biological consumption.