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Project Reports

• Characterization of Habitability and Biosignature Preservation in Cold Springs

  In an increasingly colder Mars where permafrost was thickening, mineralizing cold springs could have provided extant subsurface habitats and a means to transport evidence of subsurface life to the surface. Depending on conditions and geochemistry, these precipitates could have encapsulated a record of past life, and the residual remnants of such spring mounds could still be exposed at the martian surface. On Earth, high latitude spring systems are rare due to the relatively impermeable permafrost. However, several groups of perennial springs are located at Axel Heiberg Island in the Canadian High Arctic (~80°N). With mean annual air temperatures of -17°C and permafrost depths ≥ 600 meters, these springs flow throughout the year despite minimum air temperatures reaching <-50°C during winter. Thick residual icing pastes form as a result of evaporation, sublimation and freeze fractionation, the mineralogy being dominated by halite, hydrohalite, calcite, gypsum, elemental sulfur, thenardite, and mirabilite. These springs provide an environment where prokaryotes thrive despite extreme conditions and their presence suggests that such systems could have been present throughout Mars history, and activated during cyclical climate changes.The primary goal of this investigation is to evaluate the potential of spring deposits in regions with thick, continuous permafrost and define their taphonomic window and biogeological context. Samples of icing pastes, travertine and other mineral precipitates have been sampled to understand the relationships between geochemistry, environment, presence of biosignatures and their potential preservation.

  ROADMAP OBJECTIVES: 2.1 4.1 7.1

• Rock Sample Biosignature Library and Automated Identification of Biosignatures

  The goals of this project are to: 1) build a Raman spectra and imaging library of rock samples containing biosignatures as no publically available online sample library currently exists; and to: 2) use this library as testing and training sets to develop automated classifiers for identifying biosignatures in rock spectra. Building a sample library and developing automated classifiers would enable field scientists or robotic explorers on the surface of Mars or elsewhere to automatically identify biosignatures in rock samples from Raman spectra out in the field.

  ROADMAP OBJECTIVES: 1.1 2.1 7.1

• Environmental and Biological Signatures in Yellowstone National Park Silica Precipitating Hot Springs

  Radiation from the Sun potentially affects solids, liquids, and gases found on the surfaces of planets. Radiation exposure could change the chemical and mineralogical make-up of the surface materials. Sample-return missions aim to collect samples, cache them for a period of time, and then return them to Earth for additional analysis. We have performed field experiments to document environmental radiation levels and exposures and their impact on recently formed materials and associated organic matter.

  ROADMAP OBJECTIVES: 1.1 2.1 6.1 7.1 7.2

• Lake Sediment Habitats; Lake Habitability and Sediment Biosignatures

  Regions where lakes and ponds existed once existed on Mars martian are among the highest priority environments for exploration. The physicochemical and biological characteristics of the unique of perennially ice-covered lake ecosystems found on earth in Antarctica, the High Arctic, and in high altitude environments (Altiplano and High Andes) serve as important analogs of earily Mars. Active and abundant microbial communities live in these extreme environments, suggesting the presence of habitable conditions on early on Mars. Unlike temperate lakes, these ecosystems are largely dominated and constrained by their physical environment (e.g., mean annual temperatures near or well below 0°C, with arid or hyper-arid conditions year-round). In these environments, lake sediments accumulate organic biosignatures due to relatively low metabolic rates and cold water. Less understood is their preservation potential once the water evaporates, and sediments are exposed to extreme cold and hyper-arid conditions. Perennially ice-covered lakes are rare on Earth. Their dry, paleo-counterparts are even more exotic, and biosignature preservation in such lake deposits remains largely unstudied. Lake Untersee, one of the largest perennially ice-covered surface lakes in East Antarctica hosts a robust microbial ecosystem including the presence of photosynthetic microbial mats that colonize the lake bottom to depths greater than 100m. These mats are primarily composed of filamentous cyanophytes and form two distinct macroscopic structures – cm-scale cuspate pinnacles dominated by Leptolyngbya spp. and laminated, large conical stromatolites that rise up to 0.5 m above the lake floor, dominated by Phormidium spp. (Andersen et al. 2011). Adjacent to Lake Untersee is the Aurkjosen Cirque, a basin that was once inundated by a large lake which has since evaporated. Desiccated, buried microbial mats have been recovered from this paleo- lacustrine site, and they provide material for the identification of biosignatures and their preservation in and extremely cold setting. Our investigations include the studies of the physical and biogeochemical characteristics of the two lakes, deposition and preservation of biomarkers, and in situ analytical techniques (IR reflectance, Raman, XRD/XRF) to identify organic signatures within a mineralogical context while developing synergistic operational concepts for in situ analyses in paleolake analogs.

  ROADMAP OBJECTIVES: 2.1 4.1 7.1

• Detection of Biosignatures

  The project is developing methods of interpreting data, detecting novelty, and identifying biosignatures in data at multiple scales (Figure 1). Investigation will improve detection and decrease diagnostic uncertainty in selecting high-probability regions and high-priority samples. In year one, objectives are to develop algorithms for orbital data analysis and feature extraction and to develop algorithms for novelty detection.

  ROADMAP OBJECTIVES: 2.1 2.2 7.1 7.2

• Biosignature Capture and Preservation in Sulfate Evaporite Deposits

  Sulfate minerals are regarded as key exploration targets for Mars sample return. These minerals form in liquid water over a broad range of environmental conditions, thus providing sensitive measures of past habitability. We are studying the preservation potential of fossil kerogen in Miocene sulfate deposits of the Camp Verde Formation, central AZ. The primary tools used in the study were selected to emulate capabilities of the Mars 2020 payload. Our results suggest ways to enhance in situ kerogen detection in sulfates, as well as operational synergies that may improve mission operations.

  ROADMAP OBJECTIVES: 2.1 7.1

• Mars Analogs: Habitability and Biosignatures in the Atacama Deser

  This project focuses on the study of habitability in the Atacama Desert of northern Chile, one of the driest regions on Earth. We want to understand how life adapts and survives in an environment where liquid water is exceedingly rare, and how biosignatures are preserved in that environment after microorganisms die. These studies can become a very useful guide for future robotic missions to Mars. This year we focused on microbial communities that inhabit the interior of salt nodules in evaporitic lake deposits. These are the only known active microbial comunities in the driest parts of the Atacama. We wanted to understand how these microbial communities survive in an environment that excludes every other form of life. We suspected that the salt communities use atmospheric water vapor as a source of water to run their metabolic processes. We showed that this is indeed the case with a combination of field and laboratory tools. Our results suggest that the salt substrate could be one of the last possible habitats for life in extremely dry environments.

  ROADMAP OBJECTIVES: 2.1 5.1 5.3 6.1 6.2 7.1 7.2

• Biomarker Profiling Using the Life Detector Chip (LDChip)

  We have worked on the detection of molecular biomarkers in three relevant environments: Dry (Atacama), acidic (Río Tinto) and deep lake sediments (Andean lakes). Samples have been analyzed in situ by using a powerful biomarker detection chip with and antibody microarray sensor as well in the laboratory with other geomicrobiological tools.

  ROADMAP OBJECTIVES: 5.3 6.1 7.1

• Understanding Ancient Aqueous Environments on Mars

  Project 1: The goal of this project is to characterize ancient aqueous environments on Mars using Digital Terrain Model (DTM) analysis and mapping to understand the potential environments for past habitability. These include fluvial environments with morphological evidence for ponding, associated with hydrothermal systems and multiple episodes of surface and near surface flow in channelized systems. We will determine sediment and eroded volumes of fluvial landforms from DTM analysis and use transport equations and terrestrial analogs to understand likely discharges and flow durations.

  ROADMAP OBJECTIVES: 1.1 2.1 7.1

• Characterizing Carbonate Outcrops on Mars

  Carbonate-rich rocks have been proposed for decades as a possible sink for a thicker CO₂-rich atmosphere on early Mars. We are mapping new detections of carbonates in ancient (Noachian) rocks in several regions of the martian southern highlands. These rocks represent enticing astrobiological targets for understanding paleo-environments, habitability and carbon cycling via in situ study with a future landed mission.

  ROADMAP OBJECTIVES: 2.1

• Remote Sensing of Ancient Habitable Environments on Mars

  We are investigating variations in clay chemistry on Mars using CRISM, HiRISE and HRSC imagery. Initial work is focusing on the Mawrth Vallis region where aqueous outcrops are known to be varied and expansive. The mineralogy of these aqueous outcrops are under study in order to characterize and document changes in the environmental chemistry over time.

  ROADMAP OBJECTIVES: 2.1