Creating a New England Salt Marsh Sediment Profile: Methods and Implications for Climate Change Mitigation Strategies

Salt marshes and other blue carbon systems (mangroves, sea grasses) sequester large amounts of carbon primarily through sedimentation and therefore naturally aid in climate change mitigation. However, disturbances caused by anthropogenic activity (agriculture, ditching, invasive species, construction) are leading to New England salt marsh habitat destruction. The loss of this carbon sink could result in the system becoming a carbon source, potentially contributing to climate change rather than abating it. In this study, a sediment profile of a temperate New England salt marsh was created. Vernier sensors were used to collect both discrete sediment samples (soil pH) and in situ sediment samples (soil salinity, soil moisture, soil temperature) weekly for one year (June 2018 – June 2019) at the Neponset River Salt Marsh in Boston, Massachusetts. The objective was to observe seasonal variations in sediment between two locations dominated by different types of marsh vegetation (Spartina alterniflora and Spartina patens). Soil pH was determined to not seasonally differ at either location. Soil pH and temperature showed no difference between soils under different types of marsh vegetation. At both locations, soil salinity, soil moisture, and soil temperature were significantly different between each season. Additionally, soil moisture and salinity were significantly different between locations in the summer and autumn. This work shows how marshes may respond to future climate scenarios, particularly increased temperatures and increased sea-level.