Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes, Rhode Island, 2016

The accretion history of fringing salt marshes in Narragansett Bay, Rhode Island, was reconstructed from sediment cores. Age models, based on excess lead-210 and cesium-137 radionuclide analysis, were constructed to evaluate how vertical accretion and carbon burial rates have changed during the past century. The Constant Rate of Supply (CRS) age model was used to date six cores collected from three salt marshes. Both vertical accretion rates and carbon burial increased from 1900 to 2016, the year the data were collected. Cores were up to 90 cm in length with dry bulk density ranging from 0.07 to 3.08 grams per cubic centimeter and carbon content 0.71 percent to 33.58 percent.