Processes influencing marsh elevation change in low- and high-elevation zones of a temperate salt marsh

Estuaries and Coasts
University of Virginia; East Carolina University
By: , and 

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Abstract

The movement of salt marshes into uplands and marsh submergence as sea level rises is well documented; however, predicting how coastal marshes will respond to rising sea levels is constrained by a lack of process-based understanding of how various marsh zones adjust to changes in sea level. To assess the way in which salt-marsh zones differ in their elevation response to sea-level change, and to evaluate how potential hydrologic drivers influence the response, surface elevation tables, marker horizons, and shallow rod surface elevation tables were installed in a Virginia salt marsh in three zones that differed in elevation and vegetation type. Decadal rates of elevation change, surface accretion, and shallow subsidence or expansion were examined in the context of hydrologic drivers that included local sea-level rise, flooding frequency, hurricane storm-surge, and precipitation. Surface elevation increases were fastest in the low-elevation zone, intermediate in the middle-elevation zone, and slowest in the high-elevation zone. These rates are similar to (low- and middle-marsh) or less than (high-marsh) local rates of sea-level rise. Root-zone expansion, presumably due to root growth and organic matter accumulation, varied among the three salt marsh zones and accounted for 37%, but probably more, of the increase in marsh surface elevation. We infer that, during marsh transgression, soil-forming processes shift from biogenic (high marsh) to minerogenic (low marsh) in response, either directly or indirectly, to changing hydrologic drivers.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Processes influencing marsh elevation change in low- and high-elevation zones of a temperate salt marsh
Series title Estuaries and Coasts
DOI 10.1007/s12237-020-00796-z
Year Published 2020
Language English
Publisher Springer
Contributing office(s) Patuxent Wildlife Research Center
Description 16 p.
Country United States
State Virginia
County Northampton
Other Geospatial Phillips Creek Marsh
Online Only (Y/N) Y
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