Effects of global change on Mackenzie River Delta

River delta regions along the Arctic coast are poorly understood ecosystems that are expected to change rapidly as the climate warms, sea levels rise, and seasonal river ice jams become less frequent. In northern Canada's Mackenzie River Delta, flood pulses driven by ice breakup control the degree to which river water moves off-channel to replenish nearby lakes, which only exist because of such river dynamics.

Lesack and Marsh analyze more than 30 years of data on the Mackenzie Delta and find that the duration of river-to-lake connection has lengthened on average more than 30 days since the 1970s. Further, the duration of river-to-lake connection has shortened in the highest elevation lakes, likely owing to the declining effects of river-ice breakup. The authors conclude that not only are the higher elevation lakes at risk of drying up from declining water level peaks, but lower elevation lakes now contain more water than can be accounted for through sea level rise, suggesting that increasing storm surge intensity, permafrost melting, or backwater flow might play an unexpected role.


Posted by: Tyler    Source