The detection of organic matter in terrestrial snow and ice: implications for astrobiology

The discovery of icy bodies in our Solar System has opened up the possibility that life may exist on and below their surfaces. Snow and ice are good sites for the preservation of biomarkers as they trap and preserve organic matter that is deposited onto their surfaces. Terrestrial samples of snow and ice collected from Ben Macdui in north east Scotland have been analysed for organic compounds contained within them. A range of n-alkanes and n-alkanoic acids were found in both samples. The particulate matter contained proportionally more higher weight n-alkanols than the melted water. This is because higher molecular weight molecules are less soluble in water. Therefore, the volume of snow and ice to be sampled on other icy bodies is an important factor, as many important biomarkers have high molecular weights and may not be detected in small quantities of melted water.