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

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

Project Photo

By examining temperature and sedimentation patterns in Coos Bay estuary, this team built on previous hydrodynamic simulations of the estuary to provide users with a dynamic picture of estuary habitat, optimal locations for native species restoration, and potential impacts of climate change and land use changes, like removal of tide gates or dredging.


The Project

South Slough National Estuarine Research Reserve (SSNERR) is located in the ecologically, economically, and culturally important Coos Bay estuary. Coos Bay is home to Oregon’s largest deep-draft port, as well as critical estuarine ecosystems including eelgrass and native oyster beds. However, water quality deterioration, climate change, and land use changes threaten the resiliency of the estuary and its marine species. In some parts of the estuary, recent restoration efforts of native oysters have failed and eelgrass density has significantly declined. To better understand the environmental factors impacting estuarine habitat, the project team worked closely with partners to examine temperature and sedimentation changes in the estuary.

This work built on previous collaborative efforts among state agencies, tribal governments, and university partners who all share a need for an improved understanding of estuary processes. The project added water temperature as a dynamic variable to an existing hydrodynamic simulation of the estuary, integrating it with new comprehensive analyses of sedimentation and salinity changes over seasonal to decadal timescales. This more expansive model (built on a model from an earlier collaborative project) allows estuary stakeholders to explore multiple stressors at once (e.g., how higher temperatures from more frequent marine heat waves interact with sediment processes from episodic storm events to affect eelgrass and oyster beds?)

Model results will be used by SSNERR and other partners to identify priority areas for eelgrass and native oyster restoration projects. For example, model results about sediment burial events due to episodic storm events will be leveraged to guide and inform more resilient restoration projects. Further, the project has facilitated deeper collaboration among partners in the area, increased access to long-term monitoring data, and provided technical and educational tools to better maintain a healthy, productive, and resilient estuary.

The Impact

  • Sustained and deepened collaborative partnerships that were developed during a previous collaborative project.
  • Deepened knowledge of how Coos Bay estuary responds to climate change events, like marine heat waves and episodic storm events, and human activities, like dredging.
  • Improved understanding of the efficacy of long-term sea level rise monitoring data by integrating short-term and long-term data records (e.g., Site Elevation Table records).
  • Inclusion of water temperature in the estuary hydrodynamic modeling to quantify the time different species spend in stressful conditions (e.g., high temperatures, high suspended sediment load), which will inform the siting of oyster and eelgrass restoration projects.
  • Increased educational opportunities for visitors of SSNERR and the Oregon Institute of Marine Biology’s Charleston Marine Life Center to learn about local and regional impacts of climate change and sedimentation.