Buried or Fried? Understanding Sedimentation and Temperature Effects on Native Species in the South Slough Reserve and Coos Estuary, Oregon

Coos Bay is home to Oregon’s largest deep-draft port, as well as critical estuarine ecosystems including eelgrass and native oyster beds. The Coos estuary has been impacted by and is vulnerable to natural and human causes of environmental decline. In some parts of the estuary, native oysters that were once extirpated are recovering but, in the South Slough branch, this has not occurred and restoration efforts have failed. In addition to supporting patchy native oyster populations, some areas of the Coos estuary host thriving native eelgrass beds, which provide critical food and habitat for juvenile fish, invertebrates, and waterfowl. However, in other parts of the estuary, eelgrass density has precipitously declined in recent years. The success of native oyster recruitment and eelgrass health are of primary concern to many end users in the Coos estuary, such as the South Slough Reserve, natural resource and coastal managers, land use planners, and research, education, and community organizations. To help inform management decisions going forward, this project will investigate the impacts of water quality deterioration, climate change, and land use changes on native oyster and eelgrass beds in the Coos estuary.

The project team will examine how temperature and sediment affect oysters and eelgrass in the Coos estuary using both observational and modeling approaches, leveraging existing data and a recently validated hydrodynamic model of the Coos estuary. The project will provide comprehensive analyses of sedimentation and water temperature changes over seasonal to decadal timescales, recommendations for future restoration efforts, and specific end user-identified outputs such as educational programs and GIS layers applicable to management objectives. This work will improve collaboration among agencies in the area, increase the success of restoration efforts, increase access to long-term monitoring data, and enhance understanding of estuarine processes across the region. The team will work iteratively with a diverse group of end users who share a need for an improved understanding of estuary processes. Together, they will combine state-of-the-art science with identified management needs to maintain a healthy, productive, and resilient estuary.