Flow and nutrient dynamics in a subterranean estuary (Waquoit Bay, MA, USA) : field data and reactive transport modeling
Slomp, Caroline P.
Charette, Matthew A.
MetadataShow full item record
A two-dimensional (2D) reactive transport model is used to investigate the controls on nutrient (NO3-, NH4+, PO4) dynamics in a coastal aquifer. The model couples density dependent flow to a reaction network which includes oxic degradation of organic matter, denitrification, iron oxide reduction, nitrification, Fe2+ oxidation and sorption of PO4 onto iron oxides. Porewater measurements from a well transect at Waquoit Bay, MA, USA indicate the presence of a reducing plume with high Fe2+, NH4+, DOC (dissolved organic carbon) and PO4 concentrations overlying a more oxidizing NO3--rich plume. These two plumes travel nearly conservatively until they start to overlap in the intertidal coastal sediments prior to discharge into the bay. In this zone, the aeration of the surface beach sediments drives nitrification and allows the precipitation of iron oxide, which leads to the removal of PO4 through sorption. Model simulations suggest that removal of NO3- through denitrification is inhibited by the limited overlap between the two freshwater plumes, as well as by the refractory nature of terrestrial DOC. Submarine groundwater discharge is a significant source of NO3- to the bay.
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 72 (2008): 3398-3412, doi:10.1016/j.gca.2008.04.027.
Showing items related by title, author, creator and subject.
Effects of nutrients, salinity, pH and light:dark cycle on the production of reactive oxygen species in the alga Chattonella marina Liu, Wenhua; Au, Doris W. T.; Anderson, Donald M.; Lam, Paul K. S.; Wu, Rudolf S. S. (2007-06-03)Experiments were carried out to investigate the effects of nutrients, salinity, pH and light:dark cycle on growth rate and production of reactive oxygen species (ROS) by Chattonella marina, a harmful algal bloom (HAB) ...
Correction to “Decadal analysis of hydrography and in situ nutrient budgets in the western and eastern North Atlantic subtropical gyre” Cianca, Andrés; Helmke, Peer; Mourino, Beatriz; Rueda, María José; Llinas, Octavio; Neuer, Susanne (American Geophysical Union, 2008-03-07)
Decadal analysis of hydrography and in situ nutrient budgets in the western and eastern North Atlantic subtropical gyre Cianca, Andrés; Helmke, Peer; Mourino, Beatriz; Rueda, María José; Llinas, Octavio; Neuer, Susanne (American Geophysical Union, 2007-07-24)The current debate about the mechanisms and magnitude of new nutrient input to the euphotic zone in subtropical gyres calls for studies which consider large and mesoscale perspectives by combining in situ time series and ...