Carbon flow from volcanic CO2 into soil microbial communities of a wetland mofette

The ISME Journal
By: , and 

Links

Abstract

Effects of extremely high carbon dioxide (CO2) concentrations on soil microbial communities and associated processes are largely unknown. We studied a wetland area affected by spots of subcrustal CO2 degassing (mofettes) with focus on anaerobic autotrophic methanogenesis and acetogenesis because the pore gas phase was largely hypoxic. Compared with a reference soil, the mofette was more acidic (ΔpH ~0.8), strongly enriched in organic carbon (up to 10 times), and exhibited lower prokaryotic diversity. It was dominated by methanogens and subdivision 1Acidobacteria, which likely thrived under stable hypoxia and acidic pH. Anoxic incubations revealed enhanced formation of acetate and methane (CH4) from hydrogen (H2) and CO2 consistent with elevated CH4 and acetate levels in the mofette soil. 13CO2 mofette soil incubations showed high label incorporations with ~512ng13Cg(dry weight (dw)) soil−1d−1 into the bulk soil and up to 10.7ng 13Cg(dw) soil−1d−1 into almost all analyzed bacterial lipids. Incorporation of CO2-derived carbon into archaeal lipids was much lower and restricted to the first 10cm of the soil. DNA-SIP analysis revealed that acidophilic methanogens affiliated withMethanoregulaceae and hitherto unknown acetogens appeared to be involved in the chemolithoautotrophic utilization of 13CO2. Subdivision 1 Acidobacteriaceae assimilated 13CO2 likely via anaplerotic reactions because Acidobacteriaceae are not known to harbor enzymatic pathways for autotrophic CO2 assimilation. We conclude that CO2-induced geochemical changes promoted anaerobic and acidophilic organisms and altered carbon turnover in affected soils.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Carbon flow from volcanic CO2 into soil microbial communities of a wetland mofette
Series title The ISME Journal
DOI 10.1038/ismej.2014.148
Volume 9
Issue 3
Year Published 2015
Language English
Publisher Nature Publishing Group
Contributing office(s) National Research Program - Eastern Branch
Description 14 p.
First page 746
Last page 759
Online Only (Y/N) N
Additional Online Files (Y/N) N