Compound climate extremes in a shoulder season altered hydrologic connectivity and abruptly transformed Arctic lakes of West Greenland

We investigated the response of lakes in West Greenland to compound climate extremes (both record heat and rainfall) associated with a series of atmospheric rivers in autumn 2022. West Greenland lakes are among the 25% of total circumpolar lake area situated in arid, low relief regions. We compared early and late summer 2023 responses to those collected in all previous years (2013-2019 early summer, 2021 and 2022 late summer). Lakewater isotopes were depleted, indicating reduced evaporation in autumn 2022; the altered hydrology substantially increased terrestrial-aquatic linkages.  Throughout summer 2023, lake color was more than 220% higher than all previous years, leading to a coherent transition from “blue” to “brown” lakes in less than a year, with water clarity reduced by 50%, owing to changes in DOM quality and increased iron concentrations. Implications for planktonic communities will also be discussed. The abrupt transformation of these lakes highlights how the timing of compound extreme events determines the strength of effects.

Primary Presenter: Jasmine Saros, University of Maine (jasmine.saros@maine.edu)

Authors:

Vaclava Hazukova, University of Maine  (vaclavahazukova@gmail.com)

Robert Northington, Elizabethtown College  (northingtonr@etown.edu)

Grayson Huston, University of Maine  (grayson.huston@maine.edu)

Avery Lamb, University of Maine  (avery.lamb@maine.edu)

Amanda Gavin, University of Maine  (amanda.gavin@maine.edu)

Sean Birkel, University of Maine  (birkel@maine.edu)

Ryan Pereira, Heriot Watt University  (R.Pereira@hw.ac.uk)

Suzanne McGowan, Netherlands Institute of Ecology  (S.McGowan@nioo.knaw.nl)