Residence time in a chain of Arctic Alaskan lagoons
The coastal Arctic is experiencing environmental change, influencing water quantity via shifting freshwater inputs, circulation, and biogeochemical dynamics. Residence time is often used to link material transport to water quality and biogeochemical processes, as it influences the retention and transformation of water and associated material.Ìý
To characterize residence time, we analyze its drivers and patterns in five connected lagoons around Kaktovik in Arctic Alaska for nearly ice-free conditions in 2019 (Jul-Sep) using a hydrodynamic model (ROMS). These lagoons vary in river influence, shelf connectivity, and water depth. The model accounts for winds, rivers, shelf circulation, tides, and bathymetry, and tracks neutrally buoyant particles released throughout the lagoons.Ìý
Preliminary results suggest that residence time is generally longer in lagoons that are deeper and more protected from nearby ocean currents. These protected lagoons had more uniformly high residence times of two to three weeks, while the residence time in shelf-connected lagoons ranged from a few days to about a week. Winds and rivers were the main drivers of residence time, and their variability caused residence time to vary in time. Overall, our results suggest that Arctic Alaskan lagoons may respond differently to changing environmental conditions based on the bathymetry and geometry of bays and inlets, and underscore the importance of considering both physical transport and retention when assessing change in the coastal Arctic.