Fe-Si biominerals in the Vilyuchinskie hot springs, Kamchatka Peninsula, Russia Autores/as Natalia L. Belkova Graduate School of Science and Technology, Kanazawa University, Kanazawa, Japan; and Limnological Institute, Siberian Division of Russian Academy of Sciences, Irkutsk, Russia Julia R. Zakharova Limnological Institute, Siberian Division of Russian Academy of Sciences, Irkutsk, Russia Kazue Tazaki Department of Earth Sciences, Faculty of Science, Kanazawa University, Kanazawa, Japan Viktor M. Okrugin Institute of Volcanology, Far-Eastern Division of Russian Academy of Sciences, Petropavlovsk-Kamchatskii, Russia Valentina V. Parfenova Limnological Institute, Siberian Division of Russian Academy of Sciences, Irkutsk, Russia Palabras clave: hot springs, microbial mats, biomats, Fe-minerals, Kamchatka Peninsula Resumen The micromorphological structure of microbial mats (biomats) from the hot springs of the Vilyuchinskaya hydrothermal system, Kamchatka Peninsula, Russia, were investigated. The Vilyuchinskie hot springs had a discharge temperature of 55–56°C and Na-Ca-HCO3-type waters rich in silicic and boric acids. Water and biomats had high concentrations of Fe, Mn, Sr, and As. Enumeration of total bacterial abundance (TBA) demonstrated a low density of bacterial populations. However, the fractions of metabolically active bacteria and respiring iron-oxidizing bacteria in the hot-spring water were high, comprising 68 and 21% of TBA, respectively. Scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (SEM-EDX) showed that unicellular rod-shaped bacteria about 5-μm long predominated in the brown biomats. The mineral capsules of these bacteria contained large amounts of Fe and Si. Extracellular and intracellular particles were observed by transmission electron microscopy. Fe-oxidizing bacteria were isolated from the biomats on agar plates with selective medium. Therefore, it can be concluded that microorganisms inhabiting the biomats of the Vilyuchinskie hot springs are essential for the deposition of Fe-minerals at neutral pH. [Int Microbiol 2004; 7(3):193–198] Descargas PDF (English) Publicado 2010-02-28 Número Vol. 7 Núm. 3 (2004) Sección Research Articles Licencia Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.