Laura Riendeau, BSc
L. Riendeau1, D. Archibald1, J. McNichol2
1Department of Earth and Environmental Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
2Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
Microbes inhabit almost every environment on Earth and their community compositions are highly dependent on abiotic environmental gradients. These abiotic environments include different rock types that can have very different chemical compositions. The objective of this research is to investigate the influence of rock geochemistry on distributions in microbial communities, with a focus on lithium, an important chemical element for decarbonization. Biological applications to mineral exploration are growing in popularity and will be a valuable tool as the demand for critical minerals increases. Microbial biodiversity is being investigated using metabarcoding of rock surface biofilms on outcrops in the Hayman Hill area located near St. Stephen, New Brunswick. The study area is located in the St. Croix terrane of Ganderia and the local geology consists of plutonic rocks, including mainly diorite, granodiorite and muscovite-biotite granite, and spodumene pegmatite dykes that intruded metasedimentary rocks. Small (<2 cm diameter and <0.5 cm thick) rock chips were collected from different rock types for 3-domain metabarcoding, a process that generates a total community fingerprint of eukaryotic and prokaryotic rRNA barcodes that can identify organisms down to the species level and determine their relative abundances. Absolute abundances per unit of exposed surface area were determined by normalizing to three internal standards. Preliminary results show a diverse biofilm community of prokaryotic and eukaryotic microbes and success of a novel DNA extraction method from rock chips. Current work is focused on comparing the rock surface metabarcodes to whole-rock geochemical data from the same samples. Taken together, this study uncovers the relationships between rock type, geochemistry, and microbial community composition on rock surfaces in the study area.