Impact of seabed resuspension on oxygen and nitrogen dynamics in the northern Gulf of Mexico : a numerical modeling study
Moriarty, Julia M.
Harris, Courtney K.
Friedrichs, Marjorie A. M.
MetadataShow full item record
KeywordRegional Ocean Modeling System (ROMS); Northern Gulf of Mexico continental shelf hypoxia; Sediment transport and resuspension; Particulate organic carbon (POC); Nitrogen; Oxygen
Resuspension affects water quality in coastal environments by entraining seabed organic matter into the water column, which can increase remineralization, alter seabed fluxes, decrease water clarity, and affect oxygen and nutrient dynamics. Nearly all numerical models of water column biogeochemistry, however, simplify seabed and bottom boundary layer processes and neglect resuspension. Here we implemented HydroBioSed, a coupled hydrodynamic‐sediment transport‐biogeochemical model to examine the role of resuspension in regulating oxygen and nitrogen dynamics on timescales of a day to a month. The model was implemented for the northern Gulf of Mexico, where the extent of summertime hypoxia is sensitive to seabed and bottom boundary layer processes. Results indicated that particulate organic matter remineralization in the bottom water column increased by an order of magnitude during resuspension events. This increased sediment oxygen consumption and ammonium production, which were defined as the sum of seabed fluxes of oxygen and ammonium, plus oxygen consumption and ammonium production in the water column due to resuspended organic matter. The increases in remineralization impacted biogeochemical dynamics to a greater extent than resuspension‐induced seabed fluxes and oxidation of reduced chemical species. The effect of resuspension on bottom water biogeochemistry increased with particulate organic matter availability, which was modulated by sediment transport patterns. Overall, when averaged over the shelf and on timescales of a month in the numerical model, cycles of erosion and deposition accounted for about two thirds of sediment oxygen consumption and almost all of the sediment ammonium production.
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 7237-7263, doi:10.1029/2018JC013950.
Suggested CitationJournal of Geophysical Research: Oceans 123 (2018): 7237-7263
The following license files are associated with this item:
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International
Showing items related by title, author, creator and subject.
Burdige, David J.; Long, Matthew; Zimmerman, Richard C. (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: firstname.lastname@example.org, 2019-03-20)This dataset includes oxygen profiles from sediment core samples collected in the northern Gulf of Mexico in May 2017. For a complete list of measurements, refer to the full dataset description in the supplemental file ...
Dissolved oxygen and potential density measurements from the R/V Atlantis, R/V Ronald Brown, & E/V Nautilus in the Gulf of Mexico & Florida from 2010-2014 (Lophelia OA project) Cordes, Erik E. (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: email@example.com, 2019-05-13)Dissolved oxygen and potential density measurements from the R/V Atlantis, R/V Ronald Brown, & E/V Nautilus in the Gulf of Mexico & Florida from 2010-2014 (Lophelia OA project) For a complete list of measurements, refer ...
Fine-grained sedimentation on the Chenier Plain Coast and inner continental shelf, northern Gulf of Mexico Draut, Amy E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2003-06)This thesis examines the evolution of a mud-dominated coastal sedimentary system on multiple time scales. Fine-grained systems exhibit different properties and behavior from sandy coasts, and have received relatively ...