Earlier ice melt increases hypolimnetic oxygen despite regional warming in small Arctic lakes

• Published in: Limnology and Oceanography Letters
• Main Authors: Hazuková, Václava, Burpee, Benjamin T., Northington, Robert M., Anderson, N. John, Saros, Jasmine E.
• Other Authors: Directorate for Biological Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: Arctic; Greenland
• Online Access: http://dx.doi.org/10.1002/lol2.10386; https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lol2.10386

Abstract Although trends toward earlier ice‐out have been documented globally, the links between ice‐out timing and lake thermal and biogeochemical structure vary spatially. In high‐latitude lakes where ice‐out occurs close to peak intensity of solar radiation, these links remain unclear. Using a long‐term dataset from 13 lakes in West Greenland, we investigated how changing ice‐out and weather conditions affect lake thermal structure and oxygen concentrations. In early ice‐out years, lakes reach higher temperatures across the water column and have deeper epilimnia. Summer hypolimnia are the warmest (~ 11°C) in years when cooler air temperatures follow early ice‐out, allowing full lake turnover. Due to the higher potential for substantive spring mixing in early ice‐out years, a warmer hypolimnion is associated with higher dissolved oxygen concentrations. By affecting variability in spring mixing, the consequences of shifts in ice phenology for lakes at high latitudes differ from expectations based on temperate regions.