The Pivotal Role of Evaporation in Lake Water Isotopic Variability Across Space and Time in a High Arctic Periglacial Landscape

• Published in: Water resources research 2024-10, Vol.60 (10), p.n/a
• Main Authors: Akers, Pete D., Kopec, Ben G., Klein, Eric S., Bailey, Hannah, Welker, Jeffrey M.
• Format: Article
• Language: English
• Subjects: Annual precipitation; Annual weather; Arctic; Arctic environments; Arctic region; Arctic zone; Climate; Climate change; Deuterium; deuterium‐excess; Disruption; Environmental impact; Environmental monitoring; Evaporation; Greenland; Hydrologic processes; Hydrologic studies; Hydrology; Isotope composition; Isotopes; Lake water; Lakes; landscapes; Monitoring; Paleoclimate; paleoclimatology; Polar waters; Precipitation; Regional hydrology; Snowmelt; space and time; Spatial variability; Spatial variations; stable isotope; Summer; Surface water; Surveys; Threat evaluation; Tracers; Variability; Water; Water analysis; Water distribution; water isotope; Water sampling
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/2023WR036121

Rapidly changing climate is disrupting the High Arctic's water systems. As tracers of hydrological processes, stable water isotopes can be used for high quality monitoring of Arctic waters to better reconstruct past changes and assess future environmental threats. However, logistical challenges typically limit the length and scope of isotopic monitoring in High Arctic landscapes. Here, we present a comprehensive isotopic survey of 535 water samples taken in 2018 and 2019 of the lakes and other surface waters of the periglacial Pituffik Peninsula in far northwest Greenland. The δ18O, δ2H, and deuterium‐excess values of these samples, representing 196 unique sites, grant unprecedented insight into the environmental drivers of the regional hydrology and water isotopic variability. We find that the spatial variability of lake water isotopes can best be explained through evaporation and the hydrological ability of a lake to replace evaporative water losses with precipitation and snowmelt. Temporally, summer‐long evaporation can drive lake water isotopes beyond the isotopic range observed in precipitation, and wide interannual changes in lake water isotopes reflect annual weather differences that influenced evaporation. Following this, water isotope samples taken at individual times or sites in similar periglacial landscapes may have limited regional representativeness, and increasing the spatiotemporal extent of isotopic sampling is critical to producing accurate and informative High Arctic paleoclimate reconstructions. Overall, our survey highlights the diversity of isotopic compositions in Pituffik surface waters, and our complete isotopic and geospatial database provides a strong foundation for future researchers to study hydrological changes at Pituffik and across the Arctic. Plain Language Summary Water isotopes can help us track how rapidly changing climate is disrupting High Arctic water systems, but the challenging Arctic environment has limited the monitoring required to understand these isotopes. To address this, we collected 535 water isotope samples from lakes and other waters on the Pituffik Peninsula in northwest Greenland in 2018 and 2019. We found that differences in lake water isotopes are mainly due to water evaporation and how connected a lake is to sources of precipitation and snowmelt that can replace evaporated water in the summer. The information we collected about isotopes is a good starting point for other scientists who want to study h