Chemical and microbiological investigations of hot spring deposits found at the hydrothermal systems of Kamchatka Peninsula, Russia

Chemical and biological characteristics of hot spring water, travertines and microbial mats collected from seven hydrothermal systems of the Kamchatka Peninsula, Russia are described. Water quality of the Vilyuchinskie hot springs was almost the same as those of Tazaki et al. (2003). Elemental concentration of hot spring waters was mainly composed of Na, K, Ca, and Mg with high contents of Fe, As, and Sr. The structure and elemental composition of travertine and biomats were studied with optical microscopy, ED-XRF, XRD, and EPMA. High content of As (43.88 wt%) was found in the deposits and biomats of the Nalychevskie hot springs. Extremely high concentration of Cd of 9.56 wt% was detected in the deposits of the Paratunskie hot springs. Traces of mercury (0.57 wt%) were found in the soft parts of biomats from the Apapelskie-1 hot springs. Optical microscopic observation of thin section of Oksinskie, Apapelskie, and Vilyuchinskie biomats revealed laminated structures. Soft parts of biomats mainly consist of cyanobacteria Anabaena spp. and green algae. A calcareous travertine of the Vilyuchinskie hot springs recorded the evidences of a long-term transition of water chemistry and periodic changes of environmental conditions such as water flux from the well and rainfall. Intensive hydrothermal alteration was observed in the Dachnye hot springs. Optical microscopic observation of microbial mats revealed diversity of microorganisms both in free-living forms and in association with mineral particles. Metabolically active cells were detected in the microbial mats indicating the impact of bacteria to the geochemical processes in the surroundings environments.