Quahog Bay has experienced reduced water quality, including low dissolved oxygen (DO), for at least the past twelve years. This embayment is considered one of the most environmentally challenged in Casco Bay. Previous Dissolved Oxygen Monitoring Projects have revealed hypoxic conditions at depth and high organic carbon concentrations in the sediment, suggesting high sediment oxygen demand. These conditions are present regardless of temperature or salinity stratification in the water column (Doan 2005a). Additionally, relatively high sediment oxygen demand has been documented in Quahog Bay (Bridges 2003). In 2005, the Dissolved Oxygen Monitoring Project attempted to determine the underlying causes behind these conditions by looking at how water moves into and out of the bay. Restricted water flow would contribute to increased sedimentation and accumulation of organic matter, resulting in high bacterial respiration and low DO.
Doan, R.M. (2007). Dissolved Oxygen Monitoring Project Final Report 2006. Portland, ME: University of Southern Maine, Muskie School of Public Service, Casco Bay Estuary Partnership.