Hydrochemical and isotopic baselines for understanding hydrological processes across Macquarie Island

A comprehensive island-wide survey of Macquarie Island reveals that groundwater significantly influences lake hydrochemistry and hydrology, a factor previously overlooked. This study used stable isotope ratios (δ13C, δ18O, δ2H) and strontium isotopic ratios (87Sr/86Sr) to analyze 40 lakes, identifying distinct geochemical drivers such as sea spray aerosols on the western side and water–rock interactions in lower elevation catchments. Lakes at higher elevations were found to be more dilute, while those at lower elevations contained terrestrial-sourced ions, likely from groundwater. These findings provide critical baseline data for understanding nutrient cycling and ecosystem health, with implications for predicting shifts due to climate change.

Meredith, K. T., Saunders, K. M., McDonough, L. K., & McGeoch, M. (2022). Hydrochemical and isotopic baselines for understanding hydrological processes across Macquarie Island. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-25115-3