Acidic Cave-Wall Biofilms Located in the Frasassi Gorge, Italy
作者:
Luminita Vlasceanu, Serban M. Sarbu, Annette S. Engel, Brian K. Kinkle,
期刊:
Geomicrobiology Journal
(Taylor Available online 2000)
卷期:
Volume 17,
issue 2
页码: 125-139
ISSN:0149-0451
年代: 2000
DOI:10.1080/01490450050023809
出版商: Informa UK Ltd
关键词: Acidophilic Biofilms Chemoautotrophic Speleogenesis Sulfobacillus Thiobacillus
数据来源: Taylor
摘要:
Acidic biofilms present on cave walls in the sulfidic region of the Frasassi Gorge, Italy, were investigated to determine their microbial composition and their potential role in cave formation and ecosystem functioning. All biofilm samples examined had pH values < 1.0. Scanning electron microscopy of the biofilms revealed the presence of various filaments and rods associated in large clusters with mineral crystals. Qualitative energy-dispersive x-ray analysis was used to determine that the crystals present on the cave walls, associated with the microbial biofilm, were composed of calcium and barium sulfate. Ribosomal RNA-based methods to determine the microbial composition of these biofilms revealed the presence of at least two strains of potential acidophilic, sulfur-oxidizing bacteria, belonging to the generaThiobacillusandSulfobacillus. An acid-producing strain ofThiobacillussp. also was obtained in pure culture. Stable isotope ratio analysis of carbon and nitrogen showed that the wall biofilms are isotopically light, suggesting that in situ chemoautotrophic activity plays an important role in this subsurface ecosystem.
点击下载:
PDF (648KB)
返 回