Groundwater Ages in Intertill and Buried Valley Aquifers in Saskatchewan, Canada.

Continental glaciations during the Pleistocene Epoch created complex systems of aquifers and aquitards across many northern regions of the Earth. The low hydraulic conductivities of glacial till aquitards suggest that limited recharge will reach the underlying aquifers, potentially preserving old groundwaters. Here, we characterize the recharge history in intertill and buried valley aquifers in Saskatchewan, Canada using C, H, He δH, δO, and major ions.

Identifying and Understanding Microbial Methanogenesis in CO Storage.

Carbon capture and storage (CCS) is an important component in many national net-zero strategies. Ensuring that CO can be safely and economically stored in geological systems is critical. To date, CCS research has focused on the physiochemical behavior of CO, yet there has been little consideration of the subsurface microbial impact on CO storage.

Dissolved gases in the deep North Atlantic track ocean ventilation processes.

Gas exchange between the atmosphere and ocean interior profoundly impacts global climate and biogeochemistry. However, our understanding of the relevant physical processes remains limited by a scarcity of direct observations. Dissolved noble gases in the deep ocean are powerful tracers of physical air-sea interaction due to their chemical and biological inertness, yet their isotope ratios have remained underexplored.

A new large-volume equilibration method for high-precision measurements of dissolved noble gas stable isotopes.

Rationale: Noble gases are widely used as physically based climate proxies, notably in dissolved water samples as tracers of past recharge temperature in groundwater and air-sea gas exchange processes in seawater. Recent advances in measuring large-volume samples of dissolved noble gas isotopic ratios at high precision have expanded the range of climate parameters that can be interpreted.

Methods: We build on prior methods for measuring noble gas stable isotopes at high precision with a new large-volume equilibration (LVE) method wherein sample gases are equilibrated in the sample flask between the dissolved phase and the headspace.

Rapid microbial methanogenesis during CO storage in hydrocarbon reservoirs.

Carbon capture and storage (CCS) is a key technology to mitigate the environmental impact of carbon dioxide (CO) emissions. An understanding of the potential trapping and storage mechanisms is required to provide confidence in safe and secure CO geological sequestration. Depleted hydrocarbon reservoirs have substantial CO storage potential,, and numerous hydrocarbon reservoirs have undergone CO injection as a means of enhanced oil recovery (CO-EOR), providing an opportunity to evaluate the (bio)geochemical behaviour of injected carbon.