Salinity, water table, and subsurface resistivity data from migrating marsh–forest ecotones

Upland habitats are converting to salt marsh at unprecedented rates due to sea level rise. While increasing salinity is understood to be the main driver of this conversion of upland to marsh, the factors that influence salinity in the zone of change (i.e., the marsh-forest ecotone) are unclear, especially in the northeastern USA, where marsh migration studies are less common. This study examined spatial and temporal patterns in salinity across the marsh-forest ecotone and potential drivers using a combination of groundwater well measurements and geophysical surveys. Across three study sites, groundwater salinity was influenced by multiple factors, including topography, weather events, and tidal cycles. Electrical resistivity tomography (ERT) showed differing patterns among sites: at the Massachusetts site, there was a sharper transition from low to high resistivity moving from the marsh to the forest. Whereas at the New Jersey and New York sites, there was a low resistivity (high salini..., To examine temporal and spatial variability across the mash-forest ecotone, we used a combination of geophysical surveys (electrical resistivity imaging) and groundwater well salinity meters.
Study Sites
Three locations showing signs of forest retreat were selected within the Atlantic coastal pine barrens ecoregion: Egg Harbor, New Jersey (39.3259°, -74.6502°), Pine Neck, New York (40.8422°, -72.5644°), and Waquoit Bay, Massachusetts (41.5562°, -70.5057°). These sites differ in tide range, slope, and vegetation composition along the marsh-forest transition but share common characteristics of the pine barrens ecoregion, which is known for its sandy, fast-draining soils (Forman 2012).
At Waquoit Bay, the study focused on the Sage Lot Pond marsh, a back-barrier marsh within the Waquoit Bay National Estuarine Research Reserve. Common species along the ecotone included Iva frutescens, Baccharis halimifolia, Toxicodendron radicans, Phragmites australis, Nyssa sylvatica, and Pinus rigida. Pine..., # Conductivity, water table elevation, and subsurface resistivity data from migrating marsh–forest ecotones

This dataset includes water level, specific conductivity, electrical resistivity, and soil data collected at marsh–forest ecotones in Egg Harbor, NJ; Waquoit Bay, MA; and Pine Neck, NY.

## Files Included

### 1. Water Level and Specific Conductivity Data

Files:

* `WaterLevels_SPC_metadata.csv`
* `EH_2024EDT.csv`
* `PN_2024.csv`
* `WB_2024EDT.csv`

#### WaterLevels_SPC_metadata.csv

This file contains metadata for 6 wells along marsh–upland ecotones and 3 tidal channel loggers. Missing values are filled with `-999`.

**Fields:**

* `Well_ID` — Names of wells
* `location` — Site name: `Waquoit`, `Pine_Neck`, or `Egg_Harbor`
* `latitude` — Decimal degrees north
* `longitude` — Decimal degrees west (negative)
* `installation_year` — Year wells were installed
* `inner_diameter` — Inner diameter of wells (m)
* `outer_diameter` — Outer diameter of wells (m)
* `well_top_elevation` — E...,