Reconstructing productivity patterns using geoduck shells

Investigators: Jennifer Eccles, Correigh Greene (NOAA)

This research activity reconstructs historical annual primary production patterns in Puget Sound basins using growth increment data from geoduck shells. Preliminary findings suggest we can assess primary production over the past 40+ years with this technique. Geoduck samples from multiple Puget Sound basins are being analyzed and compared with existing data sources of algal biomass inferred from chlorophyll measurements to test whether geoduck growth correlates with primary production throughout Puget Sound and whether interannual growth in geoduck shells relates to annual variation in marine survival of Chinook and coho salmon. These data allow researchers to determine how primary productivity affects salmon marine survival.

Geoduck growth rings. Photo credit Bethany Stevick.