(Georgia Institute of Technology, 2022-05-03)
Sutton, Scot M.
From 2016 to 2018, the FELDSPAR team visited the Dyngjusandur, Iceland, Mars analog plains to characterize the importance of spatial separation and abiotic measurements for extraterrestrial sampling protocols and the predictivity of biosignatures. The FELDSPAR team has approached analog sampling with the goal of emulating the protocols and instruments available on board the Mars 2020 Perseverance Rover so as to inform future missions and optimize science return. The Dyngjusandur plains are primarily comprised of fine basaltic tephra, ideal for investigating biological variability at visually homogenous sampling sites. Samples were collected using a schematic of nested triangles established over three years of field campaigns, designed to allow for statistical comparisons between samples at multiple spatial scales. Characteristic factors analyzed for each sample included: ATP, dsDNA, gravimetric moisture content, and grain size composition. Data from 2016-2018 was analyzed to identify shifts in these characteristic factors over time and the dependance of their relationships on spatial groupings and environmental factors. Aeolian action was found to be a primary source of biosignature variability at Dyngjusandur, with biomass content increasing at sampling sites with environmental protection from the wind. Grain size fractions were also influential for bioactivity and biomass with both ATP and dsDNA positively correlating with larger sediment grains. Samples collected with 10 m of separation were most likely to be significantly different, while samples separated by 1 m were found to be statistically similar. Samples collected at 100 m of separation were often significantly different, however more comparisons are necessary to characterize the variability of biosignatures at larger scales. This work provides additional evidence to influence sampling protocols for approaching Martian targets with similar environmental stresses, and the patterns uncovered over three years of study serve as a starting point for deeper characterization of the Icelandic Mars analog.