The Volcanism and the Geochemistry of the Soil and Vegetation in Kamchatka. Part 3. The Elemental Composition of Vegetation in Volcanic Ecosystems

Abstract

The relationship between the chemical composition of plants and the active volcanism of Kamchatka is determined by the fact that the dominant chemical elements for the plants, volcanic ashes, and soils are invariably Ca, Mg, Mn, P, Cu, Zn, and Sr. We have found an increased geochemical background for Kamchatka plants relative to the bulk chemical composition of the soils in the peninsula. The concentrations of Br, Hg, Hf, Sb, Ga, W, and K relative to the clarkes in living matter were higher by factors of 3 to 5 in the plants of this region. While the concentrations of chemical elements in plants of different areas are subject to little variation, we found a relatively rich biogeochemical background in the Western Area of Southern Province (the western coast of Kamchatka); in this area the oldest (for Kamchatka) near-surface volcanic ashes have been transformed into accumulative humus horizons. It was found for the area where young volcanic ashes were deposited in the proximity of active volcanoes that the vegetation is relatively rich in chemical elements and the soils are depleted in mobile forms of elements. Farther from the volcanoes, however, in the zone where ashes of remote origin were deposited, one notes a comparative depletion in the plants and an enrichment in the soils in relation to accessible elements.