The limnological response of Arctic deltaic lakes to alterations in flood regime

• Main Authors: Ryan W. Scott (12015854), Sapna Sharma (210203), Xiaowa Wang (1324806), Roberto Quinlan (12015857)
• Format: Text
• Language: unknown
• Published: 2022
• Subjects: Evolutionary Biology; Ecology; Sociology; Inorganic Chemistry; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; trace metal data; recent historic high; year time series; variable flood conditions; increasing connection time; whole .</ p; via channel connections; suggests productivity declines; global climate change; 2 </ sub; lake water chemistry; examine limnological changes; arctic deltaic lakes; connection time; climate change; lake chemistry; work suggests; flood regime; arctic freshwaters; lake number; variables related; unique five; strongly related; rich lakes; rapidly altered; previous work; poorly understood; many cases; major ion; macrophyte productivity; limnological response; individual lakes; including years; growing season; elevation lakes; Arctic; Mackenzie Delta; Climate change
• Online Access: https://doi.org/10.6084/m9.figshare.19089962.v1

Arctic freshwaters are being rapidly altered by global climate change with consequences to hydrology, biogeochemistry, and ecology, but in many cases the trajectory of these changes is poorly understood. We collected a unique five-year time series of major ion, nutrient, and trace metal data from lakes in the Mackenzie Delta to examine limnological changes during a period of variable flood conditions, including years of recent historic high and low peak river levels. Previous work in the Mackenzie Delta has established that lake water chemistry is strongly related to connection time with the river during the period of spring ice jam flooding or via channel connections through the growing season. We show that differences in peak spring water levels explain differences in lake chemistry in lakes that are isolated from the channel during the summer. Isolated, macrophyte-rich lakes in the Mackenzie Delta have been shown to be CO 2 absorbers during the summertime. We demonstrate a response to alterations in flood regime by variables related to macrophyte productivity in isolated lakes with the greatest connectivity to the river that suggests productivity declines with increasing connection time. The connectivity of low-elevation lakes, which represent a majority of lake number and area in the Delta, has been projected to increase with climate change. Our work suggests that an increase in connection time may decrease the macrophyte productivity of these lakes, with potential consequences to the CO 2 balance of individual lakes and the Delta as a whole.