Department or Program

Earth and Climate Sciences

Abstract

The purpose of this study is to evaluate the upstream and downstream carbon dynamics in the tidally restricted Drakes Island Marsh. Hydrological conditions were assessed through stream channel and pore water analyses. Short-term carbon dynamics were assessed through methane flux measurements. Sediment cores were collected to evaluate long-term carbon stocks and sequestration. Archival records and core geochemical analyses were used to understand the impacts of historic alterations. Pore water salinity was lower on the upstream side of the restriction. Methane fluxes were significantly higher on the upstream side of the marsh over three field days, with average upstream fluxes ranging between 3.09 ± 1.17 nmol/m2s and 9.13 ± 8.99 nmol/m2s, and average downstream fluxes ranging between 0.765 ± 0.504 nmol/m2s and 3.23 ± 4.20 nmol/m2s. The increased upstream methane emissions were attributed to low pore water salinity allowing for increased methanogenesis. While carbon density did not differ significantly in the upstream vs. the downstream, carbon sequestration was higher upstream of the restriction, with sequestration rates ranging between 80 gC/m2yr and 208 gC/m2yr in the upstream and 70 gC/m2yr and 137 gC/m2yr in the downstream. The elevated upstream carbon sequestration is attributed to tidal restoration in the marsh history, allowing for the rapid vegetation recovery. The findings of this study emphasize the potential for rapid carbon sequestration and suppressed greenhouse gas emissions following salt marsh tidal restoration.

Level of Access

Restricted: Embargoed [Bates Community After Expiration]

First Advisor

Johnson, Beverly

Date of Graduation

5-2024

Degree Name

Bachelor of Arts

Number of Pages

89

Components of Thesis

1 pdf file

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Embargoed

Available to Bates Community via local IP address or Bates login on Saturday, May 03, 2025.

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