Project information
Dates: 15 January 2024 – 25 August 2025
Funding: UKRI Fellowship
Unravelling the formation of unique Antarctic stromatolites by taxonomic and functional analysis: implications for the early evolution of life
Large conical stromatolites. © Dale T. Andersen and James Grecian
Lake Untersee is a perennially ice-covered lake located in Queen Maud Land, East Antarctica. This habitat serves as an ecological analogue of early Earth and other worlds in our solar system characterized by thick permanent ice covers, such as Enceladus and Europa and even ancient ice-covered lakes on Mars.
This unique environment supports a vast system of sympatric mat morphologies: cuspate pinnacles, flat mats and modern, large conical stromatolites down to depths of at least 100 meters. While pinnacles and flat mats are common throughout other Antarctic ecosystems, large complex cones are the first report of such structures in a modern environment. These stromatolites consist of a top pigmented layer of oxygenic photosynthetic Cyanobacteria covering a soft structure entirely built from alternating laminations of sediment and microbially derived organic matter. These modern organo-sedimentary cone structures are extremely intriguing as Lake Untersee is the only environment on Earth where they have been found to date.
StromatoLife aims to provide a comprehensive understanding of the taxonomy and functional ecology of the only known modern microbial structures that will increase our understanding of early Earth microbial life and the possible past habitability of Mars. The deep taxonomic and functional study of these communities represents a gap in the understanding of how microbial life cooperatively shapes complex Antarctic life and cones similar to Archaean life on Early Earth. This project will represent a major advance in our knowledge about the emergence of microbial three-dimensional structures.
Previous studies have focused on the bacterial component of these structures, but the role played by the eukaryotic and the viral community in the formation and maintenance of the large conical stromatolites in Lake Untersee remains largely unknown.
Furthermore, the functional genes and metabolic characteristics of the microbial communities have not been studied yet. Unravelling the microbial life of novel and unique microbial structures is a central priority for biologists, as these structures may harbour a high number of novel microorganisms previously unknown to science.
StromatoLife brings together an international team of collaborators from the Natural History Museum of London and the SETI Institute in the USA.
This project is highly multidisciplinary in nature as it will combine polar microbiology and freshwater microbial sciences, geobiology, microbial functionality, molecular biology, imaging, and sequencing technology. We will integrate concepts and techniques from microbial taxonomy and functionality in an effort to unravel the formation of the only known modern stromatolites.
Our team aims to unravel the factors that drive the formation, function, and metabolic and biochemical pathways as well as microbial interactions in the Lake Untersee stromatolites using an integrative approach of high-resolution confocal microscopy and SEM and high throughput metagenomic and metatranscriptomic sequencing.
DNA and RNA will be extracted from different layers within the cones and pinnacles, sequenced by way of long-read Nanopore and short-read Illumina sequencing to characterize and compare the taxonomy, genetic composition and metabolic potential of microbes inhabiting Lake Untersee. Genome assembly will allow us to determine metabolic pathways and implications in nutrient uptake and adaptations to extreme lake conditions. Confocal and Scanning Electronic Imaging will allow us to evaluate the arrangement of cyanobacteria and interactions between microbes and minerals that create conical stromatolites.
Understanding the roles of microbial behaviours forming these conical stromatolites will provide insights into the interpretation of fossil forms from Early Earth and their mechanisms for growth.
The results will also help assess the metabolic pathways of life near the limits of habitability in ice-covered crater lakes on early Mars or icy moons Enceladus and Europa. It is yet to be established why microbial biofilms are only able to form conical structures in Lake Untersee. It is not clear whether cone layers are characterized by a core taxonomy or functionality independent of location and depth within the lake and whether compositional specificity results in unique functional profiles.
Dates: 15 January 2024 – 25 August 2025
Funding: UKRI Fellowship
Greco C., Andersen D.T., Yallop M., Barker G., Jungblut, A.D. (2024) Genome-resolved metagenomics reveals diverse taxa and metabolic complexity in Antarctic lake stromatolites. [Under review]