Buried or Fried? Understanding Sedimentation and Temperature Effects - NERRS/NSC(NERRS Science Collaborative) Native Species in the South Slough Reserve and Coos Estuary, Oregon

This project addresses linkages between temperature and sedimentation and ecosystem outcomes using both observational and modeling approaches. The team leveraged the development of a realistic, validated hydrodynamic model of the Coos estuary and extended previous research effort to analyze estuary conditions over large spatial scales. The study found a striking variation in sediment deposition and erosion across the estuary that was not a simple function of distance from estuary mouth. In addition, the model suggests that high estuary temperatures coincide with eelgrass die-off while high levels of sediment accretion result in less successful oyster restoration. Model results have allowed the team and its partners to make more precise recommendations for ongoing oyster and eelgrass restoration efforts and develop user-identified outputs including educational programs.

To investigate sedimentation patterns, the team combined monitoring data from the NERRS System-wide Monitoring Program (SWMP) and Sentinel Sites with new sediment core data and new numerical model simulations. Long cores were collected to measure sediment accumulation over a longer time period (on the order of 100 years). Shorter cores were collected to obtain a yearly cycle of sediment deposition.
A second focus of the project was to add water temperature to the existing hydrodynamic model, which was previously simulating only salinity and sediment (and sea level). Temperature is an important variable to team partners interested in ecosystems and biota. In addition, the model was run for a longer period, simulating three full years of the estuary hydrodynamics, 2014-2016, which will allow more insight into processes affecting native species and prove more useful to stakeholders.