Speleothems from Sahastradhara Caves in Siwalik Himalaya, India: Possible Biogenic Inputs
2014 (English)In: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 31, no 8, 664-681 p.Article in journal (Refereed) Published
Stalactites and moonmilk from Sahastradhara caves in Siwalik Himalayas were studied to understand the role of microbes in their genesis. Fourier spectroscopy in the moonmilk indicates a complex milieu of organic compounds that is unusual for inorganic formations. Stable C and O isotopes show trends in the moonmilk and stalactite, which suggest biogenic input; the geochemical inference is consistent with evidence from microscopy and laboratory-based microbial cultures. Light microscopy of moonmilk samples show the presence of a number of microbial forms similar to Cyanobacteria, and scanning electron microscope (SEM) images show microbial structures similar to Spirulina. The total number of microbial cells using SYBR Gold is 6.5 x 10(5) cells, g sed(-1) in moonmilk and 3.2 x 10(5) cells, g sed(-1) in stalactites. FISH indicates approximately 3.5 x 10(5) cells, g sed(-1) in moonmilk and 2 x 10(5) cells, g sed(-1) in stalactites. SEM images of the moonmilk indicate a large network of microbial filaments along with minerals, which are identified as calcite based on their x-ray diffraction pattern. In vitro laboratory cultures with pure monogenic strains isolated from the moonmilk and stalactites raise pH in the medium, which facilitate calcite precipitation. The mineral precipitating isolates were identified as: Bacillus pumilis, B. cereus, B. anthracis, B. lentus, B. sphaericus, B. circulans and Actinomycetes. The Sahastradhara moonmilk and statactites are colonized by a diverse microbial community and the isolated bacterial strains induce biomineralization on different nutrient media, supporting their biogenic origin.
Place, publisher, year, edition, pages
Taylor andamp; Francis: STM, Behavioural Science and Public Health Titles , 2014. Vol. 31, no 8, 664-681 p.
bacteria; biogenic deposits; calcite; speleothem
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:liu:diva-111309DOI: 10.1080/01490451.2013.871087ISI: 000341405800003OAI: oai:DiVA.org:liu-111309DiVA: diva2:755259
Funding Agencies|Norwegian Government Scholarship Pool International Section, Norway; Swedish Institute; UGC, New Delhi; SASNET2014-10-142014-10-142014-10-23