Biologically mediated release of endogenous N2O and NO2 gases in a hydrothermal, hypoxic subterranean environment

Copyright © 2020 Elsevier B.V. All rights reserved..

The migration of geogenic gases in continental areas with geothermal activity and active faults is an important process releasing greenhouse gases (GHG) to the lower troposphere. In this respect, caves in hypogenic environments are natural laboratories to study the compositional evolution of deep-endogenous fluids through the Critical Zone. Vapour Cave (Alhama, Murcia, Spain) is a hypogenic cave formed by the upwelling of hydrothermal CO2-rich fluids. Anomalous concentrations of N2O and NO2 were registered in the cave's subterranean atmosphere, averaging ten and five times the typical atmospheric backgrounds, respectively. We characterised the thermal conditions, gaseous compositions, sediments, and microbial communities at different depths in the cave. We did so to understand the relation between N-cycling microbial groups and the production and transformation of nitrogenous gases, as well as their coupled evolution with CO2 and CH4 during their migration through the Critical Zone to the lower troposphere. Our results showed an evident vertical stratification of selected microbial groups (Archaea and Bacteria) depending on the environmental parameters, including O2, temperature, and GHG concentration. Both the N2O isotope ratios and the predicted ecological functions of bacterial and archaeal communities suggest that N2O and NO2 emissions mainly depend on the nitrification by ammonia-oxidising microorganisms. Denitrification and abiotic reactions of the reactive intermediates NH2OH, NO, and NO2- are also plausible according to the results of the phylogenetic analyses of the microbial communities. Nitrite-dependent anaerobic methane oxidation by denitrifying methanotrophs of the NC10 phylum was also identified as a post-genetic process during migration of this gas to the surface. To the best of our knowledge, our report provides, for the first time, evidence of a niche densely populated by Micrarchaeia, which represents more than 50% of the total archaeal abundance. This raises many questions on the metabolic behaviour of this and other archaeal phyla.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:747

Enthalten in:

The Science of the total environment - 747(2020) vom: 10. Dez., Seite 141218

Sprache:

Englisch

Beteiligte Personen:

Martin-Pozas, Tamara [VerfasserIn]
Sanchez-Moral, Sergio [VerfasserIn]
Cuezva, Soledad [VerfasserIn]
Jurado, Valme [VerfasserIn]
Saiz-Jimenez, Cesareo [VerfasserIn]
Perez-Lopez, Raul [VerfasserIn]
Carrey, Raul [VerfasserIn]
Otero, Neus [VerfasserIn]
Giesemann, Anette [VerfasserIn]
Well, Reinhard [VerfasserIn]
Calaforra, Jose M [VerfasserIn]
Fernandez-Cortes, Angel [VerfasserIn]

Links:

Volltext

Themen:

Critical zone
Deep endogenous gas
Gases
Journal Article
K50XQU1029
Methane
Methane oxidation
Nitrification
Nitrogen Dioxide
Nitrogen dioxide
Nitrous Oxide
Nitrous oxide
OP0UW79H66
S7G510RUBH

Anmerkungen:

Date Completed 20.10.2020

Date Revised 20.10.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.scitotenv.2020.141218

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM313524157