Numerical Model of Geochronological Tracers for Deposition and Reworking Applied to the Mississippi Subaqueous Delta

Birchler, Justin J.; Harris, Courtney K.; Kniskern, Tara A.; Sherwood, Christopher R.

doi:10.2112/si85-092.1

Cited by 3 publications

(4 citation statements)

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“…Although conserving sediment mass among a fixed number of layers is straightforward, it has proven difficult to devise a robust and efficient method that records relevant stratigraphic events in a modeled sediment bed over the wide range of conditions that occur in coastal domains. For both sediment transport and sediment bed geochemistry (i.e., Moriarty et al, 2017;Birchler et al, 2018), it can be important for the sediment bed model to achieve its highest vertical resolution near the sediment-water interface, but the original ROMS sediment bed model did not meet that goal when the sediment bed was subject to frequent or repeated cycles of erosion. The modifications we have made to the bed-layer management have improved the fidelity with which we can record stratigraphic events in the model layers, particularly at the sediment-water interface.…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, for problems of sediment geochemistry, it is important to account for the mixing of both particulate matter and porewater. Expansion of the ROMS sediment bed model to include diffusive mixing facilitates its use for interdisciplinary problems (i.e., Moriarty et al, 2017;Birchler et al, 2018). The choice of appropriate mixing parameters remains a challenge, especially when considering the spatial and seasonal heterogeneity of biological activity.…”

Section: Discussionmentioning

confidence: 99%

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Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)

et al. 2018

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Abstract. We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean-Atmosphere-WaveSediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in floc characteristics in the seabed; erosion and deposition of cohesive and mixed (combination of cohesive and non-cohesive) sediment; and biodiffusive mixing of bed sediment. These routines supplement existing noncohesive sediment modules, thereby increasing our ability to model fine-grained and mixed-sediment environments. Additionally, we describe changes to the sediment bed layering scheme that improve the fidelity of the modeled stratigraphic record. Finally, we provide examples of these modules implemented in idealized test cases and a realistic application.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)

et al. 2018

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“…In addition to idealized studies such as reported here, the geochronological model should provide useful insight if applied to realistic field settings. For example, we have used a similar one-dimensional (vertical) version of the model to represent a site offshore of the Mississippi subaqueous delta [50]. This model was implemented to replicate observed radioisotopic profiles [6].…”

Section: Future Applicationsmentioning

confidence: 99%

“…The model-produced radioisotopic profiles were then used within various analytical models from the literature to derive deposition rate, etc., from the simulated profiles; which were then compared to the actual model deposition rates. Results showed that the analytical model estimates can be unreliable if assumptions regarding the biodiffusion rate and radioisotope activity of freshly deposited sediment are incorrect [50].…”

Section: Future Applicationsmentioning

confidence: 99%

Sediment Transport Model Including Short-Lived Radioisotopes: Model Description and Idealized Test Cases

Birchler

Harris

Sherwood

et al. 2018

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Geochronologies derived from sediment cores in coastal locations are often used to infer event bed characteristics such as deposit thicknesses and accumulation rates. Such studies commonly use naturally occurring, short-lived radioisotopes, such as Beryllium-7 (7Be) and Thorium-234 (234Th), to study depositional and post-depositional processes. These radioisotope activities, however, are not generally represented in sediment transport models that characterize coastal flood and storm deposition with grain size patterns and deposit thicknesses. We modified the Community Sediment Transport Modeling System (CSTMS) to account for reactive tracers and used this capability to represent the behavior of these short-lived radioisotopes on the sediment bed. This paper describes the model and presents results from a set of idealized, one-dimensional (vertical) test cases. The model configuration represented fluvial deposition followed by periods of episodic storm resuspension. Sensitivity tests explored the influence on seabed radioisotope profiles by the intensities of bioturbation and wave resuspension and the thickness of fluvial deposits. The intensity of biodiffusion affected the persistence of fluvial event beds as evidenced by 7Be. Both resuspension and biodiffusion increased the modeled seabed inventory of 234Th. A thick fluvial deposit increased the seabed inventory of 7Be and 234Th but mixing over time greatly reduced the difference in inventory of 234Th in fluvial deposits of different thicknesses.

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A Multifaceted Approach to Advance Oil Spill Modeling and Physical Oceanographic Research at the United States Bureau of Ocean Energy Management

Smith

DuFore

et al. 2021

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The Environmental Studies Program (ESP) at the United States Bureau of Ocean Energy Management (BOEM) is funded by the United States Congress to support BOEM’s mission, which is to use the best available science to responsibly manage the development of the Nation’s offshore energy and mineral resources. Since its inception in 1973, the ESP has funded over $1 billion of multidisciplinary research across four main regions of the United States Outer Continental Shelf: Gulf of Mexico, Atlantic, Alaska, and Pacific. Understanding the dynamics of oil spills and their potential effects on the environment has been one of the primary goals of BOEM’s funding efforts. To this end, BOEM’s ESP continues to support research that improves oil spill modeling by advancing our understanding and the application of meteorological and oceanographic processes to improve oil spill modeling. Following the Deepwater Horizon oil spill in 2010, BOEM has invested approximately $28 million on relevant projects resulting in 73 peer-reviewed journal articles and 42 technical reports. This study describes the findings of these projects, along with the lessons learned and research information needs identified. We also present a path forward for BOEM’s oil spill modeling and physical oceanographic research.

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Numerical Model of Geochronological Tracers for Deposition and Reworking Applied to the Mississippi Subaqueous Delta

Cited by 3 publications

References 14 publications

Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)

Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)

Sediment Transport Model Including Short-Lived Radioisotopes: Model Description and Idealized Test Cases

A Multifaceted Approach to Advance Oil Spill Modeling and Physical Oceanographic Research at the United States Bureau of Ocean Energy Management

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