Chesapeake Bay Dissolved Oxygen Profiling

Description

Water quality impairment in the Chesapeake Bay, caused primarily by excessive long-term nutrient input from runoff and groundwater, is characterized by extreme seasonal hypoxia, particularly in the bottom layers of the deeper mainstem (although it is often present elsewhere). In addition to obvious negative impacts on ecosystems where it occurs, hypoxia represents the integrated effect of watershed-wide nutrient pollution, and monitoring the size and location of the hypoxic regions is important to assessing Chesapeake Bay health and restoration progress.

Chesapeake Bay Program direct water quality monitoring has been by necessity widely spaced in time and location, with monthly or bi-monthly single fixed stations separated by several kilometers. The need for continuous, real time, vertically sampled profiles of dissolved oxygen has been long recognized, and improvements in hypoxia modeling and sensor technology make it achievable. Recent results of Bever, et al. (2018) show that total Chesapeake Bay hypoxic volume can be estimated using a few analytically selected fixed continuous dissolved oxygen profiles.

The project is to pilot a cost-effective, real-time dissolved oxygen vertical monitoring system for characterizing mainstem Chesapeake Bay hypoxia. The approach for this project is to use a lightweight, low-powered real-time inductive CTDO2 mooring with sensors at multiple vertical measurement levels. The reports provide details on the proposed tasks for this project and expected outcomes and deliverables.