HR: 16:50h
AN: GC54A-04    [Abstracts]
TI: Coupled Pollen, Spore, and Macrofossil Hudson River Marsh Paleoecological Analysis with X-Ray Fluorescence Elemental Analysis to Study Estuarine Ecosystem Response to Anthropogenic and Climatic Changes
AU: * Sritrairat, S
EM: sanpisa@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, P.O. Box 1000, Palisades, NY 10964, United States
AU: Peteet, D M
EM: peteet@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, P.O. Box 1000, Palisades, NY 10964, United States
AU: Peteet, D M
EM: peteet@ldeo.columbia.edu
AF: NASA/Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, United States
AU: Kenna, T C
EM: tkenna@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, P.O. Box 1000, Palisades, NY 10964, United States
AU: Chillrud, S N
EM: chilli@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, P.O. Box 1000, Palisades, NY 10964, United States
AU: Kurdyla, D
AF: Lawrence Livermore Labs, Center for AMS, 7000 East Ave., L-403, Livermore, CA 94550,
AU: Guilderson, T
AF: Lawrence Livermore Labs, Center for AMS, 7000 East Ave., L-403, Livermore, CA 94550,
AB: Stockport Flats (41.3N, 73.8W) and Tivoli North Bay (42.0N, 73.9W) are the two northernmost Hudson River National Estuarine Research Reserve freshwater tidal marshes in New York. Our paleoecological records based on pollen, spores, macrofossils, and loss-on-ignition (LOI) of marsh sediment cores at these two sites suggest significant local and regional anthropogenic changes and climatic variability, including the Medieval Warming Period. We implement the use of a field portable X-Ray Fluorescence Spectroscopy (Innov-X, USA) as an independent proxy to provide more information about chronology, watershed land-use changes, and estuarine processes. Over the last 200 years, there is a pronounced decrease in organic matter, a shift in vegetation, and an increase in invasive species such as Phragmites australis, Lythrum salicaria, and Typha angustifolia. Coupling of more traditional chronological measurements, such as Ambrosia pollen rise and radiometric dating (C-14, Cs-137, and Pb-210), with heavy metals profiles (Pb, Cr, Cu, and Zn) using the XRF unit provides additional time horizon markers, as these metals have distinct peaks in the 1960s and toward the present. Dates from the XRF profiles near the top of the core help to confirm the timing and rate of vegetation changes, especially the spreading of the invasive species. Discrete metal peaks using the XRF help to quickly determine the degree of disturbances and resolution of the cores as analysis of Cs-137 profile is much slower. Sediment proxies, including Ca, K, Ti/S, and Fe/S increase while Sr and Zr decrease toward the top of the core, probably representing higher erosion from land-use changes concurrent with lithologic shifts, LOI decline, and invasive species expansion. Sulfur concentration increases many orders of magnitude especially in the Stockport core and may be a good proxy of salinity, an indicator of drought and seawater rise. This information is valuable to compare with the vegetation changes to understand how salinity and hydrology anomalies may have affected these wetlands in the past.
DE: 1051 Sedimentary geochemistry
DE: 1637 Regional climate change
DE: 1655 Water cycles (1836)
DE: 4902 Anthropogenic effects (1803, 4802)
DE: 4950 Paleoecology
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting