Developing Novel Methods to Measure Historic Wetland Accretion

I propose using historical markers down sediment cores to measure marsh accretion rates. I plan to use pollen, macrofossils, stable isotopes, radiocarbon dating and X-Ray Fluorescence Spectroscopy (XRF) to develop a high-resolution age model. Next, I plan to compare the elemental compositions down-core to a dataset generated by (1) on tributary sediment elemental composition, to trace the relative mineral inputs into wetlands through time. I will also combine this project with

improved sea level modeling for HRNERR sites. I will make all my data publicly accessible and write everything up in a broadly exportable kit for HRNERR needs.

Problem statements and proposed solutions:

Problem 1: We do not know accretion rates throughout HRNERR wetland sites, and how accretion rates change based on salinity, vegetation, and sediment flux. I plan to fix this problem by mapping accretion rates in several sediment cores throughout HRNERR sites.

Problem 2: While there are hydrodynamic models for Hudson River sediment flow, there is no empirical evidence to verify the models and trace how sediment moves through the Hudson River.

Furthermore, there is no quantitative way to trace sediments from tributaries through the estuary into wetlands. I plan to compare down-core mineral properties to a database of tributary chemical

signatures generated by a Hudson River Foundation report (1) to geochemically trace sediment sources to wetlands.

Problem 3: Current sea level models use relative sea level markers to constrain the geophysical parameters that contribute to changing global water distribution (2). However, we have major concerns about the quality of the current sea level projections because many have outdated

radiocarbon dates (bulk dating vs. macrofossil based AMS dates), and many of them include ages from Piermont Marsh, which appears to be sinking. I propose improving sea level projections with a thorough literature review of modern, published radiocarbon dates and investigating possible tectonic activity in Piermont.