This study described the investigation of microbial mats that are rich in iron, arsenic, and manganese in four hydrothermal systems of Kamchatka, Russia namely Vilyuchinskie, Mutnovskie, Nachikinskie, and Malkinskie. The hydrothermal systems (hot springs) are contributing to the metallic and non-metallic mineral resources of Russia such as oil, gas, coal, copper, nickel, cobalt, tin, mercury, lead, zinc, diamond, platinum, gold, and silver. We observed the biogeochemical activities of microorganisms originating from microbial mats. The structure and elemental composition of microbial mats in these hydrothermal systems were studied with optical microscopy and scanning electron microscopy equipped with energy dispersive X-ray analyzer (EDX), whereas the water quality of these springs was measured by using pack tests. Additionally, portable Y-ray analyzer was employed to determine the kind and quantity of Y-ray in the atmospheric condition of sampling areas. Optical and scanning electron microscopic observations revealed that the microbial mats at these springs were mainly composed of a large number of microorganisms such as bacteria (coccus, bacillus, and filamentous), cyanobacteria, and algae in association with biominerals. Bacterial fluorometric enumeration of the thermal water informed that the total number of bacteria was relatively low, while the fraction of enzymatically active bacteria was high ranging from 27 % to 91 %. Besides that, ƒﾁ-ray observation showed that the predominantly ƒﾁ-ray range was between 320-380 keV dominating in green and black-colored microbial mats at Vilyuchinskie hot springs. Correspondingly, heavy metal and minerals deposits accumulated at all these springs indicating that microorganisms may contribute to binding and formation of the minerals. These activities and heavy mineral encrustation of cyanobacteria, bacteria, and algae may contribute to the growth of the heavy metal deposit (such as iron, manganese, and arsenic) at these springs. Obviously, Kamchatka hot springs provide a model for studying the potential role of prokaryotes and eukaryotes in the origin of heavy metal and minerals formation.
田崎 et al. (Wed,) studied this question.