Cryo-micro-Raman spectroscopy and next generation sequencing for investigation of biomarkers in water ice inclusions of the subglacial antarctic lake

• Applicant: Professor Dr. Heinz-Wilhelm Hübers
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429811207

The aim of the project is to discover Lake Vostok inhabiting microorganisms, extant or extinct. The scientific potential of cryo Raman microscopy and Next Generation Sequencing (NGS) for accurate detection and identification of specific biogenic markers will be evaluated and applied for identification of organic-matter related substances in the water ice cores obtained from the subglacial Antarctic Lake Vostok. Two consequent analytical techniques will be applied to the icy samples, first without their melting and after that on the melted products. First, micro-Raman spectroscopy will enable contactless localization and identification of organic matter related substances, preventing contamination and evaporation of material entrapped in an ice matrix, solid and gaseous. Raman spectroscopy will be applied on both natural as well as artificial ice samples, and later on solid inclusions recovered from the Lake Vostok ice. The organic carbon, lipids and proteins as DNA proxy have been selected as probable specific biomarkers for Raman spectroscopy for these pristine samples with very rare solid and some volatile gas inclusions. The limits of detection for the artificial biomarker-ice samples will be determined in the frame of the project. Given a positive feedback the ice can be melted in the laboratory under clean room conditions and a solid inclusion (along with the local melt) can be reinvestigated by Raman spectroscopy along with complementary biogeochemical methods. The PCR followed by Next Generation Sequencing of extracted microbial genomic DNA along with complementary analyses (microparticle counting, SEM and AFM, organic carbon content, analytical water chemistry, cell concentration counting) will be used for the post-treated samples. The PCR and NGS sequencing will allow proving the Raman results and discover Lake Vostok inhabiting microorganisms, extant or extinct. The research will have impact on space research and astrobiology. Space missions with payloads for in-situ planetary exploration (e.g. Raman spectrometers) will search for life on Solar system bodies with oceans which are covered by ice crusts are somewhat comparable to the Lake Vostok. The search for extant or extinct extraterrestrial life as a main goal of astrobiology is based on revealing and characterization of biomarkers. The main objects to search for such life signatures are icy moons and planets featured by polar ice caps, e.g. frozen-water-rich subsurface permafrost on Mars and ice-covered oceans on Jupiter’s Europa and Saturn’s Enceladus. The samples to study are expected to be water ice containing different inclusions embedded into a tough crystalline lattice permeable for light gases (helium, hydrogen) only. The subglacial Antarctic Lake Vostok serves as a unique terrestrial analogue. The project aims to strengthen the European international cooperation between research groups actively participating in polar region research and in space research/astrobiology.

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Cooperation Partner: Dr. Sergey Bulat, until 3/2022