THE DISTRIBUTION OF DISSOLVED FORMS OF TITANIUM AND VANADIUM IN THE WATER COLUMN OF THE CASPIAN SEA

Abstract

According to the chemical analyses results of the water tests of North, average Caspian Region and, partially, South Caspian Region, selected along the profiles from different horizons of water layer, are determined the contents of the dissolved forms of titanium (Tidiss) and vanadium (Vdiss). Are given the maps of the spatial distribution of these elements in the surface and above the bottom aqueous horizons, and also on the elevations of water layer. The factors, which determine its concentration and laws governing the propagation in the sea water, are revealed for each of the studied elements. In the surface water of Caspian Sea are separated the individual sections with the increased concentrations of Tidiss exceeding background values (about 1 micrograms/l). In the North Caspian Region such regions include avandel of the Volga and Terek rivers. They were formed as a result of the natural entering of the river waters, enriched Tidiss. It is established that with the removal from the mouth to the side of the open areas of the sea the content of Tidiss decrease to the background values, due to the processes of dilution and partial absorption by phytoplankton. The small area of the increased values of Tidiss in the center section of the North Caspian Region (1,5-3 micrograms/l) was formed in one of the local cholestatic zones in the process of the concentration of the finest colloidal and pseudo-colloidal complexes. In the average Caspian Region on the surface are isolated three regions of the increased contents of Tidiss (1,5-3 micrograms/l and more). It is shown that the first is connected with the entering of element with the liquid drain of Samur river; the second, extensive, elongated under the action of cyclonal flow along the coast on the north, and the third, that occupies coastal zone, were formed as a result of delivering from the desert territories and dissolution of the unstable or moderately steady mineral-carriers of titanium. The appearance of the increased concentrations of Tidiss in the above the bottom layer of avandel of the Urals and central region is explained by biogeochemical reasons. In the distribution of Tidiss according to the vertical line of the water layer of the specific regularities not discovered. In some cases, at comparatively small depths, to the bottom-dwelling horizon its concentration decreases, in others - the reverse picture is observed: the values of titanium to the bottom-dwelling layer grow to the extreme values (more than 3 micrograms/l and above) because of the diffusion mass exchange on the border of the division of two phases («water-sediment»), dissolution of fito- zooplanktonic sediments and hydro-oxide formations of zooplanktonic. Are determined sufficiently low concentrations of Vdiss in the water layer of Caspian Sea, which is connected with its geochemical sluggishness in the exogenous processes. Local increases in its concentrations (more than 1 micrograms/l) in the surface layer are timed to the sources of entering of Vdiss, such are river the Volga and the Urals, to a lesser degree the Terek river and Samur. It is established that the supplied with the river drain of the Volga additional portions of Vdiss enrich the western part of the North Caspian Region, and with the river drain of the Urals - eastern. These two regions are demarcated, by the elongated from the north to the south, zone of minimum values of Vdiss (less than 0,7 micrograms/l). Relatively higher contents of Vdiss (0,7-1 micrograms/l) are outlined on the outer-delta spaces of the Terek and Samur rivers. The Sulak river does not render any noticeable influence on the concentration of Vdiss in the sea water. The presence of continuous strip of relatively increased contents of Vdiss (0,7-1 micrograms/l) in the center section of the average Caspian Region, which was lengthened from the West to the east from one shore to another, is caused by the concentrated action of the centripetal force of cyclonal flow. Revealed for the surface horizon laws governing the distribution of Vdiss, in essence remain also in the above the bottom horizon, with exception of avandel of river Terek, medium Caspian basins and Derbent cavities, where the concentration of Vdiss noticeably higher (more than 1 micrograms/l). From the analysis of Vdiss distribution on the sections of water layer it follows that the relatively high (more than 1 micrograms/l) and increased (0,7-1 micrograms/l) value of Vdiss timed to the bottom-dwelling and interlayers of water layer.