In the tidal marshes at San Pablo Bay National Wildlife Refuge, research ecologist Karen Thorne, PhD and biologist Chase Freeman, from the USGS Western Ecological Research Center, study how quickly sediment accumulates in the marshland over time. They use a surface elevation table (SET), a device that measures elevation change, to track soil buildup. It's important to monitor the accretion of sediment in tidal marshes, to see if the land is building elevation at a rate fast enough to keep pace with sea level rise.
Produced by Isabel Fischer
US Geological Survey, Western Ecological Research Center
San Pablo Bay National Wildlife Refuge