The U.S. Geological Survey has deployed sensors in numerous natural and managed/altered wetland settings that continuously measure wetland porewater depth and elevation and, frequently, salinity. These environmental parameters are key drivers for wetland ecological and biogeochemical properties.
The Herring River estuary (Wellfleet, Cape Cod, Massachusetts) has been tidally restricted for over a century by a dike constructed near the mouth of the river. Behind the dike, the tidal restriction has caused the conversion of salt marsh wetlands to various other ecosystems including impounded freshwater marshes, flooded shrub land, drained forested upland, and wetlands dominated by Phragmites australis. This estuary is now managed by the National Park Service, and replacement of the existing dike has begun with the objective to restore tidal flow to the estuary. To assist National Park Service land managers with restoration planning and implementation, study collaborators have been investigating differences in...
Since 2014, over 30 coastal wetland sediment cores of up to 1 meter in length have been collected across saltmarsh and mangrove ecosystems in the continental U.S. by USGS Woods Hole Coastal and Marine Science Center’s (WHCMSC) staff led by M. Eagle. Extensive measurements of radioisotopes and elemental concentrations have resultied in cores with high resolution age-models and associated carbon and vertical accretion rates. Such data are used for a variety of purposes, including: 1) wetland carbon stock assessment, 2) soil accretion rates to validate wetland models and inform resilience to sea-level rise and 3) environmental records of coastal change.
The challenge of wetland persistence is complicated by widespread management and alteration of wetland hydrology, and built infrastructure within migration corridors. Human development and utilization of coastal landscapes in the U.S. during the past several centuries has resulted in loss of approximately half of tidal wetland area, largely due to 1) restriction of tidal flows, through intentional diking and drainage or impoundment, 2) construction of levees, or road and railroad construction leading to varying degrees of impoundment, and 3) development on drained/filled wetlands with critical portions of our developed and urbanized coasts are built on drained and filled former tidal wetland. We have estimated that...
Sage Lot Pond is a small tidal embayment located in Waquoit Bay and is the site of the Salt Marsh Observatory, managed by the Waquoit Bay National Estuarine Research Reserve (WNERR). This infrastructure has supported intensive studies on wetland biogeochemical processes related to lateral export of carbon, nutrients, and other constituents; evaluation of the controls on greenhouse gas fluxes in coastal wetlands and their potential to change due to environmental change; and research on the controls of carbon cycle and other key geochemical processes within wetlands that impact their resilience and stability. The U.S. Geological Survey has conducted extensive deployment of continuous sensors, as well as made measurements...
Tidal wetland ecosystems support high rates of atmospheric carbon dioxide (CO2) sequestration, a critical climate regulating ecosystem service. Although water-saturated conditions in wetlands support anaerobic production of methane (CH4), a potent greenhouse gas, the presence of sulfate ions in seawater limits CH4 emission where tidal flow is present. The U.S. Geological Survey investigates both natural and altered wetland ecosystems to determine how greenhouse gas fluxes change in conjunction with environmental drivers as well as wetland management condition. Data is collected from both eddy flux covariance towers and discrete flux measurements from chambers. All data is accompanied by ancillary environmental measurements.
