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In the McMurdo Dry Valleys, Antarctica’s largest ice-free area, the stream channels consist of rock and soil that is underlain by permafrost. Substantial permafrost degradation and channel erosion occurred in January 2012 on the west branch of Crescent Stream, while the east branch remained unaffected. Long-term stream water chemistry samples are collected in Crescent Stream as part of the MCM LTER, and samples in the west and east branches were also collected in 2021-2023. The concentrations of major ions along with nutrients were significantly higher in the west branch than the unaffected east branch, and the average concentration of ions, as well as nitrite and nitrate, was significantly greater in Crescent Stream after the 2012 degradation than before. Our results show that while a large disturbance event can increase the solute inputs and shift the long-term average dissolved ion concentrations, the overall stream discharge-concentration relationship may remain chemostatic.Ìý