Microbial megacities fueled by methane oxidation in a mineral spring cave.
ISME J
; 12(1): 87-100, 2018 01.
Article
in En
| MEDLINE
| ID: mdl-28949325
ABSTRACT
Massive biofilms have been discovered in the cave of an iodine-rich former medicinal spring in southern Germany. The biofilms completely cover the walls and ceilings of the cave, giving rise to speculations about their metabolism. Here we report on first insights into the structure and function of the biofilm microbiota, combining geochemical, imaging and molecular analytics. Stable isotope analysis indicated that thermogenic methane emerging into the cave served as an important driver of biofilm formation. The undisturbed cavern atmosphere contained up to 3000 p.p.m. methane and was microoxic. A high abundance and diversity of aerobic methanotrophs primarily within the Methylococcales (Gammaproteobacteria) and methylotrophic Methylophilaceae (Betaproteobacteria) were found in the biofilms, along with a surprising diversity of associated heterotrophic bacteria. The highest methane oxidation potentials were measured for submerged biofilms on the cavern wall. Highly organized globular structures of the biofilm matrix were revealed by fluorescent lectin staining. We propose that the extracellular matrix served not only as an electron sink for nutrient-limited biofilm methylotrophs but potentially also as a diffusive barrier against volatilized iodine species. Possible links between carbon and iodine cycling in this peculiar habitat are discussed.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Gammaproteobacteria
/
Methylophilaceae
/
Caves
/
Methane
Country/Region as subject:
Europa
Language:
En
Journal:
ISME J
Journal subject:
MICROBIOLOGIA
/
SAUDE AMBIENTAL
Year:
2018
Document type:
Article
Affiliation country:
Germany