Matthew Quinn
Project
Meta-omics & culture-based analysis of Lost Hammer spring deep sediment microbial communitiesThe possibility of life on other celestial bodies has been prompted by the widespread and resilient nature of microbial life on Earth. Cryophilic bacteria (i.e., bacteria able to grow below 0°C) found in polar regions have exhibited metabolic activity under hypersaline, low-oxygen, and sub-zero conditions providing evidence that analogous life could theoretically survive in similar liquid water environments on Mars, Europa, or Enceladus. Indeed, Earth’s polar environments can act as valuable proxies for “off-planet” conditions and harbor a largely uncultivated pool of bacteria that have a large influence on the biogeochemical cycles of our warming planet. In these environments, the existence of previously unknown biodiversity has been elucidated through metagenomic and metatranscriptomic sequencing which allows analysis of total community DNA and mRNA. When used in parallel, these methods can provide valuable insights into microbial taxonomic community composition and in situ gene expression profiles. Multi-omics approaches have been used previously in the Whyte lab to investigate active microbial communities inhabiting the surface (top 5 cm) of the Lost Hammer (LH) spring sediment on Axel Heiberg Island. This perennial cold saline spring system runs through thick permafrost providing a globally rare environment for exploring unique polar microbial biodiversity. The LH site (79° 7′ N, 90° 21′ W) was selected because it boasts incredibly harsh conditions for life with highly saline (24% salinity) and anoxic water flowing at −5 °C. This environment is thus analogous to hypothetical brines that may exist in the Martian subsurface or that have tentatively existed on the surface of Mars during the transition from the wet Noachian to the dry Hesperian period. Moreover, LH is the coldest terrestrial greenhouse gas seep discovered to date as this site continuously outputs methane gas. Therefore, the LH spring systems represent an excellent field location and analog environment to study previously unknown microbial biodiversity in the North relevant to astrobiology and global warming. Currently, nothing is known about the microbial biodiversity found deep within the spring sediments (i.e., 30 – 50 cm depth). Therefore, metagenomic and metatranscriptomic analyses can be employed to uncover the activity and composition of the deep spring sediment microbial community. If successful, this research will provide an exciting first glimpse into previously uncharted polar biodiversity. I hypothesize that the deep LH spring sediment microbial communities will exhibit more distinctively anaerobic and oligotrophic metabolisms (i.e., methanogenesis) compared to the previously analyzed surface microbial community as the deep sediment represents a more oxygen and nutrient depleted environment. To test this hypothesis my objectives and methods are as follows: 1) Obtain 50 cm deep sediment samples from LH springs this summer using a PVC pipe method; 2) Understand the community composition and potential by obtaining mid and high quality metagenome assembled genomes via metagenomic sequencing of the collected samples; 3) Perform metatranscriptomic analysis to understand what genes are being expressed at depth and by which organisms; 4) Isolate new cryophilic bacterial species from the sediment samples using meta-omics informed predictions and traditional culturing methods (i.e., dilution to extinction method).
Keywords
Polar Microbiology, AstrobiologyPublications
1- Application of a CRISPR Sequence-Based Method for a Large-Scale Assessment of Salmonella Serovars in Ontario Poultry Production EnvironmentsQuinn, Matthew W., Nicola F. Linton, Carlos G. Leon-Velarde, Shu Chen,
2023 Applied and Environmental Microbiology
