Table 1. Description of metagenomes in this study.

Identifiers	Study Description	Reference
ERX2165959	Groundwater from monitoring wells from naphthalene contaminated surface sediments, where effluent from the coal-tar contaminated groundwater surfaces	[35]
SRX1085364	Terrestrial subsurface C, N, S and H cycles cross-linked by metabolic handoffs	[20]
SRX1775573 SRX1775577 SRX1775579	Potential for microbial H2 and metal transformations associated with novel bacteria and archaea in deep terrestrial subsurface sediments	[25]
SRX1990955	Groundwater microbial communities from Rifle, Colorado—Rifle Oxygen_injection A2 metagenome	[20]
SRX2200098	Trichloroethene-dechlorinating enrichments of contaminated groundwater	[36]
SRX2838984	Coupling Microbial Communities to Carbon and Contaminant Biogeochemistry in the Groundwater-Surface Water Interaction Zone	[37–39]
SRX3024504 SRX3024507 SRX3024508	DNA from groundwater after nitrate injection, filter size 0.2μm and 0.1μm	[40]
SRX3307784	Subsurface groundwater microbial communities from S. Glens Falls, New York, USA—GMW37 contaminated, 5.8 m metagenome	[35]
SRX3348993	Development of a pipeline for high-throughput recovery of near-complete and complete microbial genomes from complex metagenomic datasets: Groundwater sample from aquifer—Crystal Geyser CG19_WC_8/21/14_NA	[41]
SRX3574179	Investigating microbial roles in methane emission, contaminant degradation, and biogeochemical cycles in an aquifer near a municipal landfill	Laura Hug Lab; https://uwaterloo.ca/hug-research-group/
SRX3602289 SRX3602720	Groundwater microbial communities from the Äspö Hard Rock Laboratory (HRL) deep subsurface site, Sweden	Mark Dopson Lab; https://lnu.se/en/staff/mark.dopson/
SURF_D	Groundwater samples from the Sanford Underground Research Facility (SURF)	[42]

We focused on groundwater datasets because they have a higher fraction of CPR. Many of the datasets are from studies of anthropologically contaminated sites. All identifiers are SRA except for SURF_D.