Estuarine Processes, Hazards, and Ecosystems
Study Sites
Estuaries are dynamic environments where complex interactions between the atmosphere, ocean, watershed, ecosystems, and human infrastructure take place. They serve as valuable ecological habitat and provide numerous ecosystem services.
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Role of tidal wetland stability in lateral fluxes of particulate organic matter and carbon. This study demonstrates a linkage between POM/POC flux and geomorphic stability.
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Estuarine processes, hazards, and ecosystems describes several interdisciplinary projects that aim to quantify and understand estuarine processes through observations and numerical modeling.
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Estuarine processes, hazards, and ecosystems describes several interdisciplinary projects that aim to quantify and understand estuarine processes through observations and numerical modeling. Both the spatial and temporal scales of these mechanisms are important, and therefore require modern instrumentation and state-of-the-art hydrodynamic models. These projects are led from the U.S. Geological Survey's Woods Hole Coastal and Marine Science Center, but are collaborative projects that include participation from other U.S. Geological Survey offices, other federal and state agencies, and academic institutions.
Estuaries are dynamic environments where complex interactions between the atmosphere, ocean, watershed, ecosystems, and human infrastructure take place. They serve as valuable ecological habitat and provide numerous ecosystem services and recreational opportunities. However, they are modified by physical processes such as storms and sea-level rise, while anthropogenic impacts such as nutrient loading threaten ecosystem function within estuaries. This project collects basic observational data on these processes, develops numerical models of the processes, and applies the models to understand the past, present, and future states of estuaries.
Measuring parameters such as water velocity, salinity, sediment concentration, dissolved oxygen and other constituents in watersheds, tidal wetlands, estuaries, and coasts is critical for evaluating the socioeconomic and ecological function of those regions. Technological advances have made it possible to autonomously measure these parameters over timescales of weeks to months. These measurements are necessary to evaluate three-dimensional numerical models that can represent the spatial and temporal complexity of these parameters. Once the models adequately represent relevant aspects of the physical system, they can be used to evaluate possible future scenarios including sea-level rise, streamflow changes, land-use modifications, and geomorphic evolution.
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Date published: March 5, 2018Status: ActiveEstuarine Processes Model Development
We are developing new routines within the COAWST model framework to represent coupled bio-physical processes in estuarine and coastal regions. These include routines for marsh vulnerability to waves, estuarine biogeochemistry, and feedbacks between aquatic vegetation and hydrodynamics.
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Date published: February 21, 2019Status: ActiveEstuarine Processes, Hazards, and Ecosystems-Study Sites
Estuaries are dynamic environments where complex interactions between the atmosphere, ocean, watershed, ecosystems, and human infrastructure take place. They serve as valuable ecological habitat and provide numerous ecosystem services and recreational opportunities. However, they are modified by physical processes such as storms and sea-level rise, while anthropogenic impacts such as nutrient...
Contacts: Neil Kamal Ganju, Ph.D.Attribution: Woods Hole Coastal and Marine Science Center -
Date published: March 5, 2018Status: ActiveEstuarine Processes Eutrophication
Increased loadings of nutrients to estuaries have altered ecosystem function by encouraging growth of phytoplankton and macroalgae while inducing large swings in dissolved oxygen and threatening the sustainability of seagrass meadows. We are measuring and modeling these processes to understand the future trajectory of estuarine ecosystems.
Attribution: Woods Hole Coastal and Marine Science Center -
Date published: March 5, 2018Status: ActiveEstuarine Processes Tidal Wetlands
Tidal wetlands are an important geomorphic and ecological feature of the coastal zone. Our projects deal with the physical forcings that affect wetland stability over event-to-annual timescales, including wave attack, sediment supply, and sea-level rise.
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Date published: March 5, 2018Status: ActiveEstuarine Processes Coastal Hazards
Extreme tides and coastal storms transfer high water levels to estuaries through natural and managed entrances. The size of the transfer depends on the duration of the event and the geomorphology of the estuary. We use observational data and modeling scenarios to understand and spatially map this transfer at our study sites.
Attribution: Woods Hole Coastal and Marine Science Center -
Date published: March 5, 2018Status: ActiveEstuarine Processes Geomorphic Change
Changes to the geomorphic structure of estuaries impact hydrodynamics, ecosystem function, and navigation. We are implementing new methods of observing and modeling these changes using innovative field and computational approaches.
Attribution: Woods Hole Coastal and Marine Science Center
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Year Published: 2019Role of tidal wetland stability in lateral fluxes of particulate organic matter and carbon
Tidal wetland fluxes of particulate organic matter and carbon (POM, POC) are important terms in global budgets but remain poorly constrained. Given the link between sediment fluxes and wetland stability, POM and POC fluxes should also be related to stability. We measured POM and POC fluxes in eight microtidal salt marsh channels, with net POM...
Ganju, Neil Kamal; Defne, Zafer; Elsey Quirk, Tracy; Moriarty, Julia M.Attribution: Woods Hole Coastal and Marine Science Center, Natural Hazards, Coastal/Marine Hazards and Resources, United States of AmericaView Citation
Marshes are the new beaches: Integrating sediment transport into restoration planning
Recent coastal storms and associated recovery efforts have led to increased investment in nature-based coastal protection, including restoration of salt marshes and construction of living shorelines. In particular, many of these efforts focus on increasing vertical elevation through sediment nourishment, where sediment is removed from the tidal...
Ganju, Neil Kamal Salt marsh loss affects tides and sediment budget in shallow bays
The current paradigm is that salt marshes and their important ecosystem services are threatened by global climate change; indeed, large marsh losses have been documented worldwide. Morphological changes associated with salt marsh erosion are expected to influence the hydrodynamics and sediment dynamics of coastal systems. Here the influence of...
Donatelli, Carmine; Ganju, Neil Kamal; Zhang, Xiaohe; Fagherazzi, Sergio; Leonardi, Nicoletta Seagrass impact on sediment exchange between tidal flats and salt Marsh, and the sediment budget of shallow bays
Seagrasses are marine flowering plants that strongly impact their physical and biological surroundings and are therefore frequently referred to as ecological engineers. The effect of seagrasses on coastal bay resilience and sediment transport dynamics is understudied. Here we use six historical maps of seagrass distribution in Barnegat Bay, USA,...
Donatelli, Carmine; Ganju, Neil Kamal; Fagherazzi, Sergio; Leonardi, Nicoletta Dynamic interactions between coastal storms and salt marshes: A review
This manuscript reviews the progresses made in the understanding of the dynamic interactions between coastal storms and salt marshes, including the dissipation of extreme water levels and wind waves across marsh surfaces, the geomorphic impact of storms on salt marshes, the preservation of hurricanes signals and deposits into the sedimentary...
Leonardi, Nicoletta; Carnacina, Iacopo; Donatelli, Carmine; Ganju, Neil K.; Plater, Andrew James; Schuerch, Mark; Temmerman, Stijn Physical response of a back-barrier estuary to a post-tropical cyclone
This paper presents a modeling investigation of the hydrodynamic and sediment transport response of Chincoteague Bay (VA/MD, USA) to Hurricane Sandy using the Coupled Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) modeling system. Several simulation scenarios with different combinations of remote and local forces were conducted to identify the...
Beudin, Alexis; Ganju, Neil Kamal; Defne, Zafer; Aretxabaleta, Alfredo Sensitivity analysis of a coupled hydrodynamic-vegetation model using the effectively subsampled quadratures method
Coastal hydrodynamics can be greatly affected by the presence of submerged aquatic vegetation. The effect of vegetation has been incorporated into the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System. The vegetation implementation includes the plant-induced three-dimensional drag, in-canopy wave-induced streaming, and the...
Kalra, Tarandeep S.; Aretxabaleta, Alfredo; Seshadri, Pranay; Ganju, Neil K.; Beudin, Alexis Observations and a linear model of water level in an interconnected inlet-bay system
A system of barrier islands and back-barrier bays occurs along southern Long Island, New York, and in many coastal areas worldwide. Characterizing the bay physical response to water level fluctuations is needed to understand flooding during extreme events and evaluate their relation to geomorphological changes. Offshore sea level is one of the...
Aretxabaleta, Alfredo; Ganju, Neil K.; Butman, Bradford; Signell, Richard P. Development of a coupled wave-flow-vegetation interaction model
Emergent and submerged vegetation can significantly affect coastal hydrodynamics. However, most deterministic numerical models do not take into account their influence on currents, waves, and turbulence. In this paper, we describe the implementation of a wave-flow-vegetation module into a Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST)...
Beudin, Alexis; Kalra, Tarandeep S.; Ganju, Neil K.; Warner, John C. Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes
Salt marshes are valued for their ecosystem services, and their vulnerability is typically assessed through biotic and abiotic measurements at individual points on the landscape. However, lateral erosion can lead to rapid marsh loss as marshes build vertically. Marsh sediment budgets represent a spatially integrated measure of competing...
Ganju, Neil K.; Defne, Zafer; Kirwan, Matthew L.; Fagherazzi, Sergio; D'Alpaos, Andrea; Carniello, Luca Spectral wave dissipation by submerged aquatic vegetation in a back-barrier estuary
Submerged aquatic vegetation is generally thought to attenuate waves, but this interaction remains poorly characterized in shallow-water field settings with locally generated wind waves. Better quantification of wave–vegetation interaction can provide insight to morphodynamic changes in a variety of environments and also is relevant to the...
Nowacki, Daniel J. ; Beudin, Alexis; Ganju, Neil K. Quantification of storm-induced bathymetric change in a back-barrier estuary
Geomorphology is a fundamental control on ecological and economic function of estuaries. However, relative to open coasts, there has been little quantification of storm-induced bathymetric change in back-barrier estuaries. Vessel-based and airborne bathymetric mapping can cover large areas quickly, but change detection is difficult because...
Ganju, Neil K.; Suttles, Steven E.; Beudin, Alexis; Nowacki, Daniel J. ; Miselis, Jennifer L.; Andrews, Brian D. Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes
Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes...
Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.-
Date published: April 4, 2018U.S. Geological Survey Oceanographic Time-Series Data Collection
Oceanographic time-series measurements made by the U.S. Geological Survey between 1975 and the present as part of research programs. The data were collected to address specific research questions and were primarily collected over durations less than a year, using stationary platforms, with sensors near the sea floor. These data have been used to study of ocean dynamics and to validate ocean...
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Date published: March 12, 2019Conceptual marsh units for Cape Cod National Seashore salt marsh complex, Massachusetts
The salt marsh complex of Cape Cod National Seashore (CACO), Massachusetts, USA and approximal wetlands were delineated to smaller, conceptual marsh units by geoprocessing of surface elevation data. Flow accumulation based on the relative elevation of each location is used to determine the ridge lines that separate each marsh unit
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Date published: March 12, 2019
Unvegetated to vegetated marsh ratio in Cape Cod National Seashore salt marsh complex, Massachusetts
Unvegetated to vegetated marsh ratio (UVVR) in the Cape Cod National Seashore (CACO) salt marsh complex and approximal wetlands is computed based on conceptual marsh units defined by Defne and Ganju (2019). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery.
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Date published: March 12, 2019Mean tidal range in marsh units of Cape Cod National Seashore salt marsh complex, Massachusetts
This dataset displays the spatial variation of mean tidal range (i.e. Mean Range of Tides, MN) in the Cape Cod National Seashore (CACO) salt marsh complex and approximal wetlands based on conceptual marsh units.MN was based on the calculated difference in height between mean high water (MHW) and mean low water (MLW) using the VDatum (v3.5) database ( http://...
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Date published: March 12, 2019Elevation of marsh units in Cape Cod National Seashore salt marsh complex, Massachusetts
Through scientific efforts initiated with the Hurricane Sandy Science Plan, the U.S. Geological Survey has been expanding national assessment of coastal change hazards and forecast products to coastal wetlands. The intent is to provide federal, state, and local managers with tools to estimate their vulnerability and ecosystem service potential
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Date published: November 20, 2018Conceptual marsh units for Fire Island National Seashore and central Great South Bay salt marsh complex, New York
The salt marsh complex of Fire Island National Seashore (FIIS) and central Great South Bay was delineated to smaller, conceptual marsh units by geoprocessing of surface elevation data. Flow accumulation based on the relative elevation of each location is used to determine the ridge lines that separate each marsh unit.
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Date published: November 7, 2018Mean tidal range in marsh units of Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
This dataset displays the spatial variation of mean tidal range (i.e. Mean Range of Tides, MN) in the Assateague Island National Seashore and Chincoteague Bay based on conceptual marsh units defined by Defne and Ganju (2018). MN was based on the calculated difference in height between mean high water (MHW) and mean low water (MLW) using the VDatum (v3.5) database (...
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Date published: November 7, 2018
Elevation of marsh units in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Elevation distribution in the Assateague Island National Seashore (ASIS) salt marsh complex and Chincoteague Bay is given in terms of mean elevation of conceptual marsh units. The response and resilience of coastal wetlands to physical factors need to be assessed in terms of the ensuing change to their vulnerability and ecosystem services.
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Date published: November 7, 2018
Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Unvegetated to vegetated marsh ratio (UVVR) in the Assateague Island National Seashore and Chincoteague Bay is computed based on conceptual marsh units. The response and resilience of coastal wetlands to physical factors need to be assessed in terms of the ensuing change to their vulnerability and ecosystem services.
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Date published: November 7, 2018Conceptual marsh units for Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
The salt marsh complex of Assateague Island National Seashore (ASIS) and Chincoteague Bay was delineated to smaller, conceptual marsh units by geoprocessing of surface elevation data. Flow accumulation based on the relative elevation of each location is used to determine the ridge lines that separate each marsh unit while the surface slope is used to automatically assign each unit a drainage...
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Date published: October 11, 2018Mean tidal range in marsh units of Plum Island Estuary and Parker River salt marsh complex, Massachusetts
This dataset displays the spatial variation of mean tidal range (i.e. Mean Range of Tides, MN) in the Plum Island Estuary and Parker River (PIEPR) salt marsh complex based on conceptual marsh units defined by Defne and Ganju (2018). MN was based on the calculated difference in height between mean high water (MHW) and mean low water (MLW) using the VDatum (v3.5) database.
Scientific Research in Great South Bay, NY
Steve Suttles and Neil Ganju surveying the position of a deployed oceanographic platform in Great South Bay, NY
Preparing oceanographic platform in Forsythe NWR, NJ
Neil Ganju (standing) and Patrick Dickhudt preparing an oceanographic platform to measure wetland sediment transport in Forsythe NWR, New Jersey
Collecting Samples in Barnegat Bay
Box-cores provide a relatively undistributed look into the recent past to help better understand the processes contributing to sediment deposition and erosion.
Barnegat Bay, NJ Surface Sediments
Surface sediments will be analyzed for various physical parameters that will be used as initial conditions in hydrodynamic and sediment transport models.
Storm erosion at Chincoteague Bay, MD
Storm induced erosion of marsh shorelines can provide significant quantities of sediment to the bay altering the deposition patterns.
Measuring seagrass!
Measuring seagrass biomass in Chincoteague Bay, Maryland to constrain numerical models.
Flood tidal shoal
Flood tidal shoal at Barnegat Inlet, New Jersey (courtesy USGS EROS NAIP orthophotography)
Barnegat Bay, NJ sunset
Sunset over Barnegat Bay and Forsythe National Wildlife Refuge, New Jersey
Eye of the storm!
Satellite image of Hurricane Sandy (courtesy NASA GOES http://weather.msfc.nasa.gov/GOES/)
Macroalgae, seagrass, and litter oh my!
Macroalgae, seagrass, and litter in West Falmouth Harbor, MA
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Date published: May 3, 2018Focus on Estuaries and Coastal Wetlands
Estuaries and wetlands provide a critical defense against storms and sea-level rise while providing economically valuable services. How well they protect coastal communities and host diverse ecosystems is largely a function of their shape (morphology), which is controlled by factors such as sediment movement and biological feedbacks.