SEEDS Internship : Geobiology of Precambrian-analogue microbialites from hypersaline environments in Kuwait Bay

Microbialites are biologically mediated organo-sedimentary structures that dominated the oceans throughout the Precambrian (> 0.54 Gyr ago); however, at present, well-developed microbialite ecosystems are mostly confined to relatively extreme non-marine environments, such as hydrothermal systems and hyperalkaline lakes.   This project will study rare modern marine macroscopic microbialites from a hypersaline environment in Kuwait Bay. We will study the morphology of these materials using petrographic and electron microscopy observations to understand the distribution of microbial biomass and the occurrence and elemental/mineralogical compositions of inorganic phases in which microfossils are preserved. These observations will be coupled with quantitative unsupervised statistical treatments of spectroscopic data using Raman and infrared techniques to assess the distribution of organic materials and identify organic groups potential biomolecules preserved within these materials.  Using combined imaging and spectroscopic datasets, we will compare these materials to similar environments in the early Earth geological record, identifying morphological and geochemical similarities. Similarities between the environment of the studied samples and hypersaline environments on early Mars also allow these samples to be used as analogues for Mars biosignature exploration and will provide a trial run of correlated microscopy and spectroscopy on returned sedimentary samples from Mars.

Work plan: Full-time

Week 1: Literature review and introduction to samples. During this week, the student will develop their knowledge of geobiology, microbialites (modern and fossil), and the use of microbialites and environmental indicators. They will use both published literature and internet resources (e.g. materials from the international geobiology school and SEDS Online seminar series to attain a good background knowledge of current topics in geobiology. 

Week 2: Optical observations of samples. During this week, the student will use photography and optical microscopy facilities at Birkbeck to characterise microbial fabrics in the study samples, identifying regions of interest for geochemical analyses in weeks 3 to 5. Each sample will be described in terms of visible micromorphologies and fabric characterisation will be performed in terms of observed features (diversity and disparity of microbial microstructures).

Week 3: Electron microscopy of samples. During this week, the student will perform high-resolution electron microscopy of samples to visualize microbial textures at microscopic scales using SEM-EDS at Birkbeck. Quantitative elemental mapping and mineralogical characterisation will be performed using energy-dispersive X-ray spectroscopy.

Weeks 4-5: Spectroscopic characterisation of organic materials in microbialites. During these two weeks, the student will extract organic materials from the samples and analyse these powdered extracts using Raman and FTIR spectroscopy at Birkbeck. The student will identify major organic groups preserved in the materials and use unsupervised statistical approaches (e.g. principal components analysis) to quantify variance between and within samples.

Week 6: Synthesis of results and preparation of report. In the final week of the project, the student will develop links between the various datasets obtained and use this information to report their understanding of the microbial community preserved within these sub-fossil and fossil materials, with a focus on quantifying how microbial cellular morphology and organic geochemical complexity change with increasing sample age and degradation. These results will have direct implications for understanding the ancient fossil record of microbial life.

Work plan: Part-time

Week 1: Literature review and introduction to samples. During this week, the student will develop their knowledge of geobiology, microbialites (modern and fossil), and the use of microbialites and environmental indicators. They will use both published literature and internet resources (e.g. materials from the international geobiology school and SEDS Online seminar series to attain a good background knowledge of current topics in geobiology.  

Week 2: Optical observations of samples. During this week, the student will use photography and optical microscopy facilities at Birkbeck to characterise microbial fabrics in the study samples, identifying regions of interest for geochemical analyses in weeks 3 to 5. Each sample will be described in terms of visible micromorphologies and fabric characterisation will be performed in terms of observed features (diversity and disparity of microbial microstructures). 

Weeks 3-5: Spectroscopic characterisation of organic materials in microbialites. During these two weeks, the student will extract organic materials from the samples and analyse these powdered extracts using Raman and FTIR spectroscopy at Birkbeck. The student will identify major organic groups preserved in the materials and use unsupervised statistical approaches (e.g. principal components analysis) to quantify variance between and within samples. 

Weeks 5-6: Synthesis of results and preparation of report. In the final week of the project, the student will develop links between the various datasets obtained and use this information to report their understanding of the microbial community preserved within these sub-fossil and fossil materials, with a focus on quantifying how microbial cellular morphology and organic geochemical complexity change with increasing sample age and degradation. These results will have direct implications for understanding the ancient fossil record of microbial life.