Fatty Acid Recovery and Identification in Mars Analogue Soil Samples Kimberly Lykens Mentor: Michael Tuite Jet Propulsion Laboratory Planetary Chemistry & Astrobiology Group STAR Program Summer 2015

Presentation Outline ➢ Background Investigative Purpose Understanding Lipids Importance of Fatty Acids ➢ Experimental Approach Collecting Samples Total Fatty Acid Method ➢ Results West Site East Site ➢ General Conclusions

Background Potential Mars Sample Return: ➢ In situ search for biosignatures ➢ Isotopes, organics ➢ Rock and dust samples and return them to Earth Possible Missions to Other Worlds:  Europa “Holy grail of space missions” Figure 1. 5 of the 6 potential biosignatures will be detectable by the rover in Mars 2020 mission. Isotopes will not be detectable with current technology.

Investigative Purpose Atacama Desert ➢ Considered a Mars analogue ➢ Located in Chile ➢ Driest desert in the world Atacama Soil Crust ➢ Biologically active Detection Capacity ➢ Biosignatures ➢ Fatty acids ➢ Lab Procedure ➢ Future applications

Understanding Lipids  Soluble in organic solvents  Diverse range of compounds  Fatty acids defining component Fatty Acid Molecule  Saturated and unsaturated  Carbon atoms, double bonds characterize  Several types

Importance of Fatty Acids AA  Energy (metabolite)  Allows for processes  Phosopholipid bilayer  Cell membrane  Imperative for life Gram-Positive Bacteria Gram-Negative BacteriaFungi

Experimental Approach Collecting Samples Lab Method (TFA) Gas Chromatography Experimental Controls Earth-based soil Mars soil

Collecting Samples Core DrillingAtacama Desert ➢ 11 West site samples ➢ 7 East site samples ➢ Moisture varies ➢ Future core samples ➢ Sample return studies

Total Fatty Acid Method (TFA) 4.Evaporation 1.Incubation 2.Separation 3.Column Filtration 5.Gas Chromatography HCl Methylate fatty acid Toluene Top layer recovered, lowest density Remove acid Remove solids Remove water N 2 gas Fatty acid solid Redissolved Identifies methyl group Breaks into fragments Delivers graph 6.Sterilization Before repeating Clean dishware with soap/DI Heat at 550F overnight

Data Analysis GC Chromatogram FAME Standard ➢ Peak corresponds to abundance ➢ Peak represents fragment through machine ➢ Identify though NIST library

Data Analysis GC Chromatogram West SitesEast Sites Key Fatty Acids ➢ Found in plants, animals, and microorganisms Key Fatty Acids

West Site Results  Most biological activity near surface  Palmitic and stearic acid correlate  Spike of fatty acid presence near bottom of column  Fatty acids were detected

East Site Results  Most biological activity near surface  Palmitic and stearic acid correlate  Spike of fatty acid presence near bottom of column  Fatty acids detected

West and East Sites

General Conclusions Conclusions  Capacity for detecting fatty acids successful  Evidence of life found in both sites  East and West are variable Sources of Error  Composition of samples  Instrument errors  Possible procedural contamination

Future Studies Isotope Analysis  Hydrogen and carbon analysis  Evidence of atmospheric changes overtime Microbiology/Ecology Research  Investigate molecular fingerprinting  How life changes overtime Potential Sample Returns  TFA method for soil cores  Isotopic analysis

Works Cited Literature Graber, E., & Tsechansky, L. (2009). Rapid One-Step Method for Total Fatty Acids in Soils and Sediments. Soil Science Society of America Journal, 72, "Lipid Library - Lipid Chemistry, Biology, Technology and Analysis." Lipid Library - Lipid Chemistry, Biology, Technology and Analysis. American Oil Chemist Society. Web. 27 July Pictures Biological Soil Crusts-

Acknowledgements Dr. Michael Tuite, Planetary Chemistry & Astrobiology Group Kari Finstad, UC Berkely Ph.D Student Martin Matthews, STAR Master Teacher Elizabeth Nagy-Shadman, STAR Research Assistant Dr. Steve Vance, Planetary Chemistry & Astrobiology Group

Questions?