A Record of the Accumulation of Sediment and Trace Metals in A Connecticut Salt Marsh

Abstract

Publisher Summary This chapter describes the study conducted to analyze the accumulation of sediment and trace metals in a Connecticut salt marsh. In the study, peat from the Farm River salt marsh, an estuarine marsh on the submerging coast of Connecticut near New Haven, was sampled by raising essentially undisturbed, meter-long cores, and was found to record trace-metal deposition from the atmosphere and sediment erosion from the land during the past century. The activity of 210 Pb and concentrations of Fe, Mn, Cu, Zn, and Pb were measured in contiguous, 2-cm thick slices of peat. The distribution of excess 210 Pb with depth in the salt marsh, by assuming a constant flux to the surface, was used to estimate the age of sediment at the bottom of each slice. The resulting age–depth relationship was compared to the independent measure of sea-level rise recorded by the New York City tide gauge and was found to be in good general agreement. The results demonstrated that 210 Pb is quantitatively retained within the salt marsh and is not significantly redistributed after deposition. The results also support the idea that stable elements with analogous chemical properties also represent a depositional record.