Climate-Driven Changes in Dissolved Organic Carbon and Water Clarity in Arctic Lakes of West Greenland

Abstract

To assess climate-mediated terrestrial-aquatic linkages in Arctic lakes and potential impacts on light attenuation and carbon cycling, we evaluated lake responses to climate drivers in two areas of west Greenland with differing climate patterns. We selected four lakes in a warmer, drier area to compare with four lakes from a cooler, wetter area proximal to the Greenland Ice Sheet. In June from 2013–2018, we measured epilimnetic water temperature, 1% depth of photosynthetically active radiation (PAR), dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA254), DOC-normalized absorbance at 380 nm (a*380), and chlorophyll a. Interannual coherence of 1% PAR and DOC was particularly high for lakes within the warmer, drier area. This coherence suggests forcing of Arctic lake features by a large-scale driver, likely climate. Redundancy analysis showed that monthly average precipitation, winter North Atlantic Oscillation (NAO) index (NAOW), spring average air temperature, and spring average precipitation influenced the lake variables (p = 0.003, adj. R2 = 0.58). In particular, monthly average precipitation contributed to increases in soil-derived DOC quality metrics and chlorophyll a and decreased 1% PAR. Interannual changes in lake responses to climate drivers were more apparent in the warmer, drier area than the cooler, wetter area. The interannual lake responses within and between areas, associated with climate trends, suggest that with ongoing rapid climate change in the Arctic, there could be widespread impacts on key lake responses important for light attenuation and carbon cycling.