Spatial and temporal variations in sediment composition within newly restored salt marshes

Abstract

Salt marsh ecosystems are highly vulnerable to climate change and sea-level rise. Adaptation strategies such as managed realignment, or dyke realignment, allow for the growth of new salt marsh in areas where one had been previously destroyed through dyking by historical settlers. Two newly restored salt marshes in the Bay of Fundy were monitored through this study. The spatial and temporal variations in water content, organic matter content, organic carbon content and sediment grain size were examined across the salt marsh surfaces. This study found that newly restored salt marshes in the Bay of Fundy can sequester carbon immediately after restoration. Carbon sequestration values resemble those in previously restored marshes in the surrounding areas. This study determined that there is a spatial variation in sediment characteristics across the salt marsh surface. This spatial variation is tied to varying elevation within the tidal frame. Spatial variations of sediment characteristics are not exclusively consistent over time but do tend to follow the same patterns. The sediment characteristics measured at both newly restored salt marshes used in this study were compared to previously restored salt marshes in Nova Scotia. All sediment characteristics data falls within similar ranges, creating a better understanding of what sediment characteristics to expect when restoring a salt marsh in the Bay of Fundy.