Brian Yellen

University of Massachusetts Amherst

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Jonathan D. Woodruff

University of Massachusetts Amherst

Frances Griswold

University of Massachusetts Amherst

David K. Ralston

Woods Hole Oceanographic Institution

Hannah Baranes

Gulf of Maine Research Institute

W. Rockwell Geyer

Woods Hole Oceanographic Institution

Wenxiu Teng

University of Massachusetts Amherst

Sarah Fernald

Wells National Estuarine Research Reserve

Justin B. Richardson

University of Massachusetts Amherst

Timothy L Cook

University of Massachusetts Amherst

Jonathan Woodruff

University of Cambridge

Cooperative Institutions

University of Massachusetts Amherst

United States Geological Survey

Woods Hole Oceanographic Institution

Massachusetts Institute of Technology

Amherst College

United States Fish and Wildlife Service

Pacific Island Ecosystems Research Center

Woods Hole Coastal and Marine Science Center

Woodwell Climate Research Center

Northeast Climate Science Center

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Modeling Spatial Distributions of Salt Marsh Blue Carbon Using Morphometric Parameters From Lidar

Journal of Geophysical Research Earth Surface (2025)

Bonnie Turek Wenxiu Teng Qian Yu Brian Yellen Jonathan D. Woodruff

Abstract Salt marshes sequester large amounts of carbon, mainly within their deep soils. Several nationwide assessments have indicated that spatial variability of marsh soil carbon is minimal, however there's a need to further reduce carbon stock uncertainties by exploring finer‐scale variation using a process‐based modeling approach. Marsh soil properties vary spatially with several parameters, including marsh platform elevation, which controls inundation depth, and proximity to the marsh edge and tidal creek network, which control variability in relative sediment supply. We used lidar to extract these morphometric parameters from salt marshes to map soil organic carbon across a marsh at the meter scale. Soil samples were collected in 2021 from four northeast U.S. salts marshes with distinctive geomorphologies. Tidal creeks were delineated from 1‐m resolution topobathy lidar data using a semi‐automated workflow in GIS. Log‐linear multivariate regression models were developed to predict soil organic matter, bulk density, and carbon density as a function of predictive metrics at each site and across sites. Distance from tidal creeks was the most significant model predictor. Modeling marsh soil characteristics worked best in marshes with single channel hydrology. Addition of distance to the inlet and tidal range as regional metrics significantly improved cross‐site modeling. Our mechanistic approach reveals important meter‐level variation in soil characteristics across a marsh and provides motivation to continue rigorous mapping of soil carbon at fine spatial resolutions. Furthermore, carbon density values used to calculate total marsh carbon stocks should be carefully selected depending on project scale, marsh geomorphology, and desired accuracy.

Salt marsh

Brackish marsh

Soil carbon

10.1029/2024jf007676

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Citations (1)

Dynamic linear models to explore time‐varying suspended sediment‐discharge rating curves

Water Resources Research (2017)

Kuk‐Hyun Ahn Brian Yellen Scott Steinschneider

Abstract This study presents a new method to examine long‐term dynamics in sediment yield using time‐varying sediment‐discharge rating curves. Dynamic linear models (DLMs) are introduced as a time series filter that can assess how the relationship between streamflow and sediment concentration or load changes over time in response to a wide variety of natural and anthropogenic watershed disturbances or long‐term changes. The filter operates by updating parameter values using a recursive Bayesian design that responds to 1 day‐ahead forecast errors while also accounting for observational noise. The estimated time series of rating curve parameters can then be used to diagnose multiscale (daily‐decadal) variability in sediment yield after accounting for fluctuations in streamflow. The technique is applied in a case study examining changes in turbidity load, a proxy for sediment load, in the Esopus Creek watershed, part of the New York City drinking water supply system. The results show that turbidity load exhibits a complex array of variability across time scales. The DLM highlights flood event‐driven positive hysteresis, where turbidity load remained elevated for months after large flood events, as a major component of dynamic behavior in the rating curve relationship. The DLM also produces more accurate 1 day‐ahead loading forecasts compared to other static and time‐varying rating curve methods. The results suggest that DLMs provide a useful tool for diagnosing changes in sediment‐discharge relationships over time and may help identify variability in sediment concentrations and loads that can be used to inform dynamic water quality management.

Rating curve

Turbidity

10.1002/2017wr020381

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Distribution and disturbances of ditches across salt marshes of the Northeast U.S. with implications for management and restoration

Journal of Environmental Management (2025)

Erin K. Peck Julie E. Walker Katherine V. Ackerman Joel A. Carr Maureen D. Correll

Effective management of valuable coastal systems, such as salt marshes requires an understanding of the complex stressors influencing their continued threat of drowning. However, efforts to determine the effects of one potential stressor, ditches, have produced diverging results complicating management efforts. Ditches (linear trenches dug to drain salt marshes for agriculture and mosquito control) alter salt marsh hydrology, but their effects on widescale marsh function and degradation are poorly understood. We created a dataset of visible ditches and summarized ditch densities (length of ditches over area) for salt marshes of the Northeast U.S. to evaluate ditching against vulnerability metrics, including elevation and the unvegetated to vegetated marsh ratio (UVVR). We identified a scale dependency in which the larger/coarser the spatial scale of analysis, the greater the fraction of ditched salt marshes. Scale dependence explains discrepancies between previously determined ditch indices. In terms of effects on marsh vulnerability, relative elevation was not influenced by visible ditch presence. Ditch densities affected UVVR, exhibiting a multiple threshold behavior. When present at low densities, ditches have little effect on ponding; yet as ditch densities increase, UVVR (i.e., ponding) increases. The relationship between ditching and UVVR reverses at the highest ditch densities, with ponding substantially decreasing. The multiple threshold vulnerability response of Northeast salt marshes to the hydrologic influences imposed by ditching suggests restoration strategies should consider the degree of ditching rather than simply ditching presence.

Salt marsh

10.1016/j.jenvman.2025.124444

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Accumulation and transport of nutrient and pollutant elements in riparian soils, sediments, and river waters across the Thames River Watershed, Connecticut, USA

The Science of The Total Environment (2023)

Mark J. Butler Brian Yellen Oluyinka Oyewumi William B. Ouimet Justin B. Richardson

10.1016/j.scitotenv.2023.165630

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Citations (9)

A speleothem record of hydroclimate variability in northwestern Madagascar during the mid-late Holocene

The Holocene (2024)

Berry L Williams Stephen J. Burns Nick Scroxton Laurie R. Godfrey Benjamin H. Tiger

We present a continuous high-resolution precisely dated multiproxy record of hydroclimate variability at Anjohibe cave in northwestern Madagascar using speleothem AB13. The record spans from ~4484 y BP to ~2863 y BP. Stalagmite δ 18 O, δ 13 C and Sr/Ca ratios show very similar changes in hydroclimate. The mechanism controlling Sr/Ca changes, however, from prior calcite precipitation to degree of dolomite dissolution at about 4 ky BP. Our record is also in good agreement with previously published speleothem records from the same area. This agreement and multiproxy consensus indicate that AB13 provides a robust record of hydroclimate variability, including a continuous record of hydroclimate variability across the 4.2 ka event. This 4.2 ka event in Madagascar is marked by two distinct periods of drying between ~3900 y BP to 4300 y BP. A dry 4.2 ka event at this Southern Hemisphere site helps limit possible mechanisms for the event, indicating that a meridional shift to the south in the ITCZ is not responsible for the 4.2 ka event. In addition, the 4.2 ka event does not stand out as a unique dry period in our record. The longest and driest period of the record lasted ~300 years with peak dryness at ~3000 y BP. Our record differs significantly from a speleothem record from Rodrigues Island, located ~1800 km to the east of our study area in Madagascar suggesting different climatological controls on northwest Madagascar and more oceanic sites to the east.

Speleothem

Stalagmite

Intertropical Convergence Zone

10.1177/09596836231225725

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Rapid tidal marsh development in anthropogenic backwaters

Earth Surface Processes and Landforms (2020)

Brian Yellen Jonathan D. Woodruff Caroline Ladlow David K. Ralston Sarah Fernald

Abstract Tidal marsh restoration and creation is growing in popularity due to the many and diverse sets of services these important ecosystems provide. However, it is unclear what conditions within constructed settings will lead to the successful establishment of tidal marsh. Here we provide documentation for widespread and rapid development of tidal freshwater wetlands for a major urban estuary as an unintended result of early industrial development. Anthropogenic backwater areas established behind railroad berms, jetties, and dredge spoil islands resulted in the rapid accumulation of clastic material and the subsequent initiation of emergent marshes. In one case, historical aerial photos document this transition occurring in less than 18 years, offering a timeframe for marsh development. Accretion rates for anthropogenic tidal marshes and mudflats average 0.8–1.1 and 0.6–0.7 cm year −1 , respectively, equivalent to two to three times the rate of relative sea level rise as well as the observed accretion rate at a 6000+ year‐old reference marsh in the study area. Paired historical and geospatial analysis revealed that more than half of all the tidal wetlands on the Hudson River were likely triggered by anthropogenic development since the onset of the industrial era, including two‐thirds of the emergent cattail marsh. These inadvertently constructed tidal wetlands currently trap roughly 6% of the Hudson River's sediment load. Results indicate that when sediment is readily available, freshwater tidal wetlands can develop relatively rapidly in sheltered settings. The study sites serve as useful examples to help guide future tidal marsh creation and restoration efforts.

Salt marsh

Dredging

10.1002/esp.5045

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Citations (16)

Salt wedge dynamics lead to enhanced sediment trapping within side embayments in high‐energy estuaries

Journal of Geophysical Research Oceans (2017)

Brian Yellen Jonathan D. Woodruff David K. Ralston Daniel G. MacDonald David S. Jones

Abstract Off‐river coves and embayments provide accommodation space for sediment accumulation, particularly for sandy estuaries where high energy in the main channel prevents significant long‐term storage of fine‐grained material. Seasonal sediment inputs to Hamburg Cove in the Connecticut River estuary (USA) were monitored to understand the timing and mechanisms for sediment storage there. Unlike in freshwater tidal coves, sediment was primarily trapped here during periods of low discharge, when the salinity intrusion extended upriver to the cove entrance. During periods of low discharge and high sediment accumulation, deposited sediment displayed geochemical signatures consistent with a marine source. Numerical simulations reveal that low discharge conditions provide several important characteristics that maximize sediment trapping. First, these conditions allow the estuarine turbidity maximum (ETM) to be located in the vicinity of the cove entrance, which increases sediment concentrations during flood tide. Second, the saltier water in the main channel can enter the cove as a density current, enhancing near‐bed velocities and resuspending sediment, providing an efficient delivery mechanism. Finally, higher salinity water accumulates in the deep basin of the cove, creating a stratified region that becomes decoupled from ebb currents, promoting retention of sediment in the cove. This process of estuarine‐enhanced sediment accumulation in off‐river coves will likely extend upriver during future sea level rise.

Cove

Freshwater inflow

10.1002/2016jc012595

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Citations (35)

Towards High Spatial-Resolution Mapping of Suspended Particulate Matter in Global Coastal Waters Using Satellite Observations

Wenxiu Teng Qian Yu Brian Yellen Dariusz Stramski Rick A. Reynolds

10.2139/ssrn.4998385

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Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA

Geomorphology (2014)