Abstract
Organic matter (OM) accumulation in marsh soils affects marsh survival under rapid sea-level rise (SLR). This work describes the changing organic geochemistry of a salt marsh located in the Blackwater National Wildlife Refuge on the eastern shore of Chesapeake Bay that has transgressed inland with SLR over the past 35–75 years. Marsh soils and vegetation were sampled along an elevation gradient from the intertidal zone to the adjacent forest, representing a space-for-time substitution of the process of marsh transgression. Stable carbon isotope analysis of bulk OM gives evidence for a transition from C3 upland-sourced OM to C4-dominated marsh vegetation over time. The vegetative source of the OM changes along a marsh-upland mixing line from herbaceous angiosperm-sourced lignin in the lower elevation marsh to a woody gymnosperm signature at the upper border of the marsh. The results of stable isotope and lignin analyses illustrate that landward encroachment of marsh grasses results in deposition of herbaceous tissues exhibiting relatively little decay. This presents a possible mechanism for OM stabilization as marshes migrate inland. Regional index terms: USA, Maryland, Chesapeake Bay, Blackwater National Wildlife Refuge.
| Original language | English (US) |
|---|---|
| Article number | 107550 |
| Journal | Estuarine, Coastal and Shelf Science |
| Volume | 261 |
| DOIs | |
| State | Published - Oct 31 2021 |
Bibliographical note
Funding Information:KMS would like to acknowledge funding from the US Geological Survey through the Great Lakes Northern Forests Cooperative Ecosystems Unit (USGS G15AS00100 ) and the University of Minnesota Duluth. GRG acknowledges support from the USGS Ecosystems Program and the Climate and Land Use Research and Development Program. Laboratory assistance at the Large Lakes Observatory at University of Minnesota-Duluth was provided by Julia Agnich, Sarah Grosshuesch, Marissa Wheeler, and Shawn Bourgeois, and field sampling was conducted with USGS employees Patrick Brennand, Eliza MacFarland, Joel Carr, and Joshua Jones. We appreciate the assistance of Matt Whitbeck and the Blackwater National Wildlife Refuge for access to the study site and permission to conduct research on the Refuge. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Source data for this study is available publicly in the USGS Science Data Catalog ( https://doi.org/10.5066/P97H1N4E ).
Funding Information:
KMS would like to acknowledge funding from the US Geological Survey through the Great Lakes Northern Forests Cooperative Ecosystems Unit (USGS G15AS00100) and the University of Minnesota Duluth. GRG acknowledges support from the USGS Ecosystems Program and the Climate and Land Use Research and Development Program. Laboratory assistance at the Large Lakes Observatory at University of Minnesota-Duluth was provided by Julia Agnich, Sarah Grosshuesch, Marissa Wheeler, and Shawn Bourgeois, and field sampling was conducted with USGS employees Patrick Brennand, Eliza MacFarland, Joel Carr, and Joshua Jones. We appreciate the assistance of Matt Whitbeck and the Blackwater National Wildlife Refuge for access to the study site and permission to conduct research on the Refuge. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Source data for this study is available publicly in the USGS Science Data Catalog (https://doi.org/10.5066/P97H1N4E).
Publisher Copyright:
© 2021 Elsevier Ltd
Keywords
- Blue carbon
- Coastal wetland
- Lignin
- Marsh transgression
- Sea level rise