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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A Conterminous USA-Scale Map of Relative Tidal Marsh Elevation

Abstract Tidal wetlands provide myriad ecosystem services across local to global scales. With their uncertain vulnerability or resilience to rising sea levels, there is a need for mapping flooding drivers and vulnerability proxies for these ecosystems at a national scale. However, tidal wetlands in the conterminous USA are diverse with differing elevation gradients, and tidal amplitudes, making broad geographic comparisons difficult. To address this, a national-scale map of relative tidal elevation ( Z * MHW ), a physical metric that normalizes elevation to tidal amplitude at mean high water (MHW), was constructed for the first time at 30 × 30-m resolution spanning the conterminous USA. Contrary to two study hypotheses, watershed-level median Z * MHW and its variability generally increased from north to south as a function of tidal amplitude and relative sea-level rise. These trends were also observed in a reanalysis of ground elevation data from the Pacific Coast by Janousek et al. (Estuaries and Coasts 42 (1): 85–98, 2019). Supporting a third hypothesis, propagated uncertainty in Z * MHW increased from north to south as light detection and ranging (LiDAR) errors had an outsized effect under narrowing tidal amplitudes. The drivers of Z * MHW and its variability are difficult to determine because several potential causal variables are correlated with latitude, but future studies could investigate highest astronomical tide and diurnal high tide inequality as drivers of median Z * MHW and Z * MHW variability, respectively. Watersheds of the Gulf Coast often had propagated Z * MHW uncertainty greater than the tidal amplitude itself emphasizing the diminished practicality of applying Z * MHW as a flooding proxy to microtidal wetlands. Future studies could focus on validating and improving these physical map products and using them for synoptic modeling of tidal wetland carbon dynamics and sea-level rise vulnerability analyses.

Holmquist, James R. (ORCID:0000000325466766)↗
DOE OSTI2022

Accelerated sea-level rise is suppressing CO 2 stimulation of tidal marsh productivity: A 33-year study

Accelerating relative sea-level rise (RSLR) is threatening coastal wetlands. However, rising CO 2 concentrations may also stimulate carbon sequestration and vertical accretion, counterbalancing RSLR. A coastal wetland dominated by a C 3 plant species was exposed to ambient and elevated levels of CO 2 in situ from 1987 to 2019 during which time ambient CO 2 concentration increased 18% and sea level rose 23 cm. Plant production did not increase in response to gradually rising ambient CO 2 concentration during this period. Elevated CO 2 increased shoot production relative to ambient CO 2 for the first two decades, but from 2005 to 2019, elevated CO 2 stimulation of production was diminished. The decline coincided with increases in relative sea level above a threshold that hindered root productivity. While elevated CO 2 stimulation of elevation gain has the potential to moderate the negative impacts of RSLR on tidal wetland productivity, benefits for coastal wetland resilience will diminish in the long term as rates of RSLR accelerate.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Redox potential in Typha-dominated tidal brackish marsh, PIE LTER, Plum Island Sound, MA, June–December 2022

This dataset includes soil redox potential measurements collected at multiple depths within a tidal brackish wetland in the upper estuary of the Plum Island Ecosystems Long-Term Ecological Research site (PIE LTER), Plum Island Sound, Newbury, Massachusetts. Measurements were taken to evaluate temporal variation in redox potential in relation to hydrological events at three replicate locations. Data were recorded every 5 minutes using a Campbell Scientific Volt116 connected to a CR6 datalogger with SWAP instrument redox probes (ORP-30-4-B) and reference electrodes. Measurements were made at the AmeriFlux site US-PLo at four soil depths (5, 10, 15, and 30 cm). The file redox_soiltemp_2022.csv contains temperature-corrected redox values and soil temperature following Silva-Machado et al. (2024). Metadata files redox_soiltemp_dd.csv and redox_soiltemp_flmd.csv provide detailed descriptions of variables and site locations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Redox potential in Typha-dominated tidal brackish marsh, PIE LTER, Plum Island Sound, MA, 2023

This dataset includes soil redox potential measurements collected at multiple depths within a tidal brackish wetland in the upper estuary of the Plum Island Ecosystems Long-Term Ecological Research site (PIE LTER), Plum Island Sound, Newbury, Massachusetts (MA). Measurements were taken to evaluate temporal variation in redox potential in relation to hydrological events at three replicate locations. Data were recorded every 5 minutes using a Campbell Scientific Volt116 connected to a CR6 datalogger with SWAP instrument redox probes (ORP-30-4-B) and reference electrodes. Measurements were made at the AmeriFlux site US-PLo at four soil depths (5, 10, 15, and 30 cm). The file redox_soiltemp_2023.csv contains temperature-corrected redox values and soil temperature following Silva-Machado et al. (2024). Metadata files redox_soiltemp_dd.csv and redox_soiltemp_2023_flmd.csv provide detailed descriptions of variables and site locations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Upland tidal brackish marsh specific conductivity and salinity measurements, PIE LTER, Plum Island Sound, MA, 2023

This dataset includes raw and corrected specific conductivity, temperature, and calculated salinity measurements collected at 10 cm depth in a Typha angustifolia-dominated tidal brackish wetland at the upper estuary of Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research (PIE LTER) site. Measurements were taken to evaluate temporal variation in porewater salinity (a proxy for porewater sulfate concentration) in high frequency to assess soil and plant responses to changes in salinity. Measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger deployed in a well. Specific conductivity was corrected using non-linear temperature compensation, and salinity was calculated using the Practical Salinity Scale 1978 via Onset's HOBOware software. Reference conductivity measurements to correct for sensor drift were taken at the start and end of each deployment using a HACH HQ14D Portable Conductivity Meter. Data were then filtered in MATLAB to remove values logged while the sensor was out of the well or during post-deployment equilibration. Detailed metadata, including variable descriptions, sampling methods, QA/QC procedures, and site information, are provided in the files: Typha_ctd_salinity_dd.csv and Typha_MI_ctd_salinity_2023_flmd.csv.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Upland tidal brackish marsh specific conductivity and salinity measurements, PIE LTER, Plum Island Sound, MA, May-December 2022

This dataset includes raw and corrected specific conductivity, temperature, and calculated salinity measurements collected at 10 cm depth in a Typha angustifolia-dominated tidal brackish wetland at the upper estuary of Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research (PIE LTER) site. Measurements were taken to evaluate temporal variation in porewater salinity (a proxy for porewater sulfate concentration) in high frequency to assess soil and plant responses to changes in salinity. Measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger deployed in a well. Specific conductivity was corrected using non-linear temperature compensation, and salinity was calculated using the Practical Salinity Scale 1978 via Onset's HOBOware software. Reference conductivity measurements to correct for sensor drift were taken at the start and end of each deployment using a HACH HQ14D Portable Conductivity Meter. Data were then filtered in MATLAB to remove values logged while the sensor was out of the well or during post-deployment equilibration. Detailed metadata, including variable descriptions, sampling methods, QA/QC procedures, and site information, are provided in the files: Typha_ctd_salinity_dd.csv and Typha_MI_ctd_salinity_2023_flmd.csv.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

High-frequency Data Integration for Landscape Model Calibration of Carbon Fluxes Across Diverse Tidal Marshes

Terrestrial Aquatic Interfaces (TAIs), and tidal wetlands in particular, store large amounts of carbon yet are not well represented in Earth System Models (ESMs). Predictions of carbon cycling and greenhouse gas (GHG) emissions in tidal wetlands are highly uncertain. Eddy covariance (EC) towers provide ecosystem-scale GHG flux data at a temporal resolution (every 30min) that is helpful for parameterizing and improving mechanistic realism in ESMs. We propose to use a network of eddy covariance towers and standardized ancillary data streams, along with mesocosm experiments and statistical analyses, across diverse tidal wetlands of North America to develop and improve biogeochemical modeling at the TAI. Our overarching objective is to improve understanding and process-based modeling of gross primary productivity (GPP) and CH4 emission responses, both non-linear and asynchronous, to stressors including plant inundation, disturbance, salinity and nitrogen loading.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Marshes and turbid waters

There are no author-identified significant results in this report. The study of the alluvial zones of the French Atlantic littoral at a taxonomic scale which can bring out the general nature of the sediments and their geomorphic forms is being achieved with the aid of ERTS-1 imagery. It will be necessary to run as many lines as possible to study both the alluvial plains, indicating the seasonal phases of the lowest and highest humidity, as well as the turbidity of littoral waters which change in relation to the tides. A better understanding of these alluvial zones and the origin of the sedimentary forms will not be limited to theoretical interest alone, but will have practical application in numerous fields such as agriculture, shell fishing, and land reclamation.

Verger, F.↗
NASA NTRS1973

Marshes and turbid waters in the French Atlantic littoral

The author has identified the following significant results. The multispectral information provided by ERTS-1 is very rich for the coastal regions but the cloud cover, even when only partial, often cuts up the data, and lessens its practical value. The research by densitometric methods has thus far been the most fruitful. It consists of measuring densities along preferential axes. This method has enabled the investigators to perfect a system of computer cartography for the best image. Comparative study of microdensitometric transects in four MSS bands for carefully dilimited profiles on the ground, makes it possible to isolate and recognize various types of countryside: (1) countryside of coastal plains; (2) countryside of coastal sand dunes and beaches; and (3) forms and processes of offshore domains. This study shows the usefulness of the ERTS program in establishing a rapid cartography of the physiographic units of the coastal plains in the interest of a rational program of exploitation and development.

Verger, F.↗