Solute dynamics in the hyporheic mesocosm in Watershed 1 at the H.J. Andrews Experimental Forest, 2019-2020

We investigated biogeochemistry along a 12-m hyporheic mesocosm that allowed for controlled testing of seasonal and spatial water quality changes along a flowpath with fixed geometry and constant flow rate. Water quality profiles of oxygen, carbon, and nitrogen were measured at 1-m intervals along the mesocosm over multiple seasons. dissolved oxygen (DO) and temperature profiles were monitored on 18 dates between May 2019 through August 2020. Grab samples to monitor profiles of carbon, nitrogen, and various other solutes along the mesocosm were collected in December 2019 and August 2020 to provide more comprehensive biogeochemical analyses at time points when the dissolved oxygen (DO) and temperature profiles were at or near the maximum seasonal differences. Mesocosm monitoring ceased abruptly due to the Holiday Farm Fire, which burned from September through October 2020, cutting off personnel access and electrical power to the mesocosm facility.