Contextual and environmental data characterizing 138 samples from Canadian groundwater ecosystems

Groundwater ecosystems are globally widespread yet still poorly understood. We therefore investigated contextual and environmental data characterizing 138 groundwater samples from Canadian groundwater ecosystems. The chemical, physical, gas, isotopic, and microbiological measurements were taken from aquifers in the Canadian Prairie between 2015 and 2020. The study area comprised 14 major aquifers and a geographic area of ~210.000 km2. The goal of the study was to understand the links between the biogeochemistry and microbial ecology of groundwater ecosystems in diverse geological settings on a broad spatial scale. Details concerning methods, results and conclusions can be found in the associated publication by Ruff et al. 2023

Nucleotide sequences of archaeal amplicon sequence variants (ASV) from Canadian groundwater ecosystems

Groundwater ecosystems are globally widespread yet still poorly understood. We investigated the microbiology of >100 groundwater samples from 90 monitoring wells (<250m depth) located in 14 aquifers in the Canadian Prairie. This dataset contains the nucleotide sequences and taxonomy of archaeal 16S rRNA gene amplicons retrieved from groundwater samples of aquifers in the Canadian Prairie, collected between 2015 and 2020. The study area comprised 14 major aquifers and a geographic area of ~210.000 km2. The goal of the study was to understand the links between the biogeochemistry and microbial ecology of groundwater ecosystems in diverse geological settings on a broad spatial scale. Details concerning DNA extraction, sequencing and sequence analyses can be found in the associated publication by Ruff et al. 2023

Eukaryotic opportunists dominate the deep-subsurface biosphere in South Africa

Following the discovery of the first Eukarya in the deep subsurface, intense interest has developed to understand the diversity of eukaryotes living in these extreme environments. We identified that Platyhelminthes, Rotifera, Annelida and Arthropoda are thriving at 1.4 km depths in palaeometeoric fissure water up to 12,300 yr old in South African mines. Protozoa and Fungi have also been identified; however, they are present in low numbers. Characterization of the different species reveals that many are opportunistic organisms with an origin due to recharge from surface waters rather than soil leaching. This is the first known study to demonstrate the in situ distribution of biofilms on fissure rock faces using video documentation. Calculations suggest that food, not dissolved oxygen is the limiting factor for eukaryal population growth. The discovery of a group of Eukarya underground has important implications for the search for life on other planets in our solar system