Sample Collection and Return from Mars: Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments
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Show full item recordEditorial
Springer Nature
Materia
Sample collection Microbial ecology
Date
2019Referencia bibliográfica
Cockell, C. S., McMahon, S., Lim, D. S., Rummel, J., Stevens, A., Hughes, S. S., ... & Zorzano, M. P. (2019). Sample Collection and Return from Mars: Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments. Space Science Reviews, 215(7), 44.
Sponsorship
This paper was made possible by support from the Science and Technology Facilities Council (STFC). Grant: ST/R000875/1.Abstract
With no large-scale granitic continental crust, all environments on Mars are fundamentally
derived from basaltic sources or, in the case of environments such as ices, evaporitic,
and sedimentary deposits, influenced by the composition of the volcanic crust. Therefore,
the selection of samples on Mars by robots and humans for investigating habitability
or testing for the presence of life should be guided by our understanding of the microbial
ecology of volcanic terrains on the Earth. In this paper, we discuss the microbial ecology
of volcanic rocks and hydrothermal systems on the Earth. We draw on microbiological investigations
of volcanic environments accomplished both by microbiology-focused studies
and Mars analog studies such as the NASA BASALT project. A synthesis of these data emphasises
a number of common patterns that include: (1) the heterogeneous distribution of biomass and diversity in all studied materials, (2) physical, chemical, and biological factors
that can cause heterogeneous microbial biomass and diversity from sub-millimetre scales to
kilometre scales, (3) the difficulty of a priori prediction of which organisms will colonise
given materials, and (4) the potential for samples that are habitable, but contain no evidence
of a biota. From these observations, we suggest an idealised strategy for sample collection.
It includes: (1) collection of multiple samples in any given material type (∼9 or more samples),
(2) collection of a coherent sample of sufficient size (∼10 cm3) that takes into account
observed heterogeneities in microbial distribution in these materials on Earth, and (3) collection
of multiple sample suites in the same material across large spatial scales.We suggest
that a microbial ecology-driven strategy for investigating the habitability and presence of
life on Mars is likely to yield the most promising sample set of the greatest use to the largest
number of astrobiologists and planetary scientists.