TY - JOUR
T1 - Metabolt
T2 - An in-situ instrument to characterize the metabolic activity of microbial soil ecosystems using electrochemical and gaseous signatures
AU - Nazarious, Miracle Israel
AU - Zorzano, María Paz
AU - Martín-Torres, Javier
N1 - Funding Information:
Acknowledgments: We would like to thank David Fernández-Remolar and Anshuman Bhardwaj, for providing crucial advice through the experiments and in structuring this article. We acknowledge the Wallenberg Foundation and the Kempe Foundation for supporting our Mars research activities. MPZ has been partially funded by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”—Centro de Astrobiología (CSIC-INTA) and the Spanish Ministry of Science and Innovation project (ref. PID2019-104205GB-C21).
Funding Information:
We would like to thank David Fern?ndez-Remolar and Anshuman Bhardwaj, for providing crucial advice through the experiments and in structuring this article. We acknowledge the Wallenberg Foundation and the Kempe Foundation for supporting our Mars research activities. MPZ has been partially funded by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia ?Mar?a de Maeztu??Centro de Astrobiolog?a (CSIC-INTA) and the Spanish Ministry of Science and Innovation project (ref. PID2019-104205GB-C21).
Publisher Copyright:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2020/8/2
Y1 - 2020/8/2
N2 - Metabolt is a portable soil incubator to characterize the metabolic activity of microbial ecosystems in soils. It measures the electrical conductivity, the redox potential, and the concentration of certain metabolism-related gases in the headspace just above a given sample of regolith. In its current design, the overall weight of Metabolt, including the soils (250 g), is 1.9 kg with a maximum power consumption of 1.5 W. Metabolt has been designed to monitor the activity of the soil microbiome for Earth and space applications. In particular, it can be used to monitor the health of soils, the atmospheric-regolith fixation, and release of gaseous species such as N2, H2O, CO2, O2, N2O, NH3, etc., that affect the Earth climate and atmospheric chemistry. It may be used to detect and monitor life signatures in soils, treated or untreated, as well as in controlled environments like greenhouse facilities in space, laboratory research environments like anaerobic chambers, or simulating facilities with different atmospheres and pressures. To illustrate its operation, we tested the instrument with sub-arctic soil samples at Earth environmental conditions under three different conditions: (i) no treatment (unperturbed); (ii) sterilized soil: after heating at 125◦C for 35.4 h (thermal stress); (iii) stressed soil: after adding 25% CaCl2 brine (osmotic stress); with and without addition of 0.5% glucose solution (for control). All the samples showed some distinguishable metabolic response, however there was a time delay on its appearance which depends on the treatment applied to the samples: 80 h for thermal stress without glucose, 59 h with glucose; 36 h for osmotic stress with glucose and no significant reactivation in the pure water case. This instrument shows that, over time, there is a clear observable footprint of the electrochemical signatures in the redox profile which is complementary to the gaseous footprint of the metabolic activity through respiration.
AB - Metabolt is a portable soil incubator to characterize the metabolic activity of microbial ecosystems in soils. It measures the electrical conductivity, the redox potential, and the concentration of certain metabolism-related gases in the headspace just above a given sample of regolith. In its current design, the overall weight of Metabolt, including the soils (250 g), is 1.9 kg with a maximum power consumption of 1.5 W. Metabolt has been designed to monitor the activity of the soil microbiome for Earth and space applications. In particular, it can be used to monitor the health of soils, the atmospheric-regolith fixation, and release of gaseous species such as N2, H2O, CO2, O2, N2O, NH3, etc., that affect the Earth climate and atmospheric chemistry. It may be used to detect and monitor life signatures in soils, treated or untreated, as well as in controlled environments like greenhouse facilities in space, laboratory research environments like anaerobic chambers, or simulating facilities with different atmospheres and pressures. To illustrate its operation, we tested the instrument with sub-arctic soil samples at Earth environmental conditions under three different conditions: (i) no treatment (unperturbed); (ii) sterilized soil: after heating at 125◦C for 35.4 h (thermal stress); (iii) stressed soil: after adding 25% CaCl2 brine (osmotic stress); with and without addition of 0.5% glucose solution (for control). All the samples showed some distinguishable metabolic response, however there was a time delay on its appearance which depends on the treatment applied to the samples: 80 h for thermal stress without glucose, 59 h with glucose; 36 h for osmotic stress with glucose and no significant reactivation in the pure water case. This instrument shows that, over time, there is a clear observable footprint of the electrochemical signatures in the redox profile which is complementary to the gaseous footprint of the metabolic activity through respiration.
KW - Astrobiology
KW - Electrical conductivity
KW - Gas monitoring
KW - Greenhouses
KW - Metabolt
KW - Microbial metabolism
KW - Planetary analogue research
KW - Planetary exploration
KW - Redox potential
KW - Space
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UR - http://www.scopus.com/inward/citedby.url?scp=85089390322&partnerID=8YFLogxK
U2 - 10.3390/s20164479
DO - 10.3390/s20164479
M3 - Article
C2 - 32796545
AN - SCOPUS:85089390322
SN - 1424-8220
VL - 20
SP - 1
EP - 18
JO - Sensors (Switzerland)
JF - Sensors (Switzerland)
IS - 16
M1 - 4479
ER -
