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Subterranean estuary

Although a substantial body of data is available on the levels of linear alkylbenzene sulfonates (LASs) in rivers and estuaries, fewer studies have been conducted on their environmental behaviour, with reference to the mechanisms involved in their transport and to the reactivity they undergo. Studies of LAS in subterranean water and in the marine medium are scarce and have mainly been conducted in the last decade [2-6], coinciding with the development of new techniques of concentration/separation and analysis of LAS at ppb levels or less. Data on concentrations of sulfophenyl carboxylates (SPCs) are very scarce and the behaviour of these intermediates has hardly received any study. This chapter provides an overview of the current knowledge on behaviour of LAS and their degradation products in coastal environments. [Pg.778]

Coastal aquifers where SGD can actually bypass the extensive recycling of terrestrially derived materials that commonly occur in estuaries have been referred to as subterranean estuaries. ... [Pg.505]

Moore, W.S. (1999) The subterranean estuary a reaction zone of groundwater and sea water. Mar. Chem. 65, 111-125. [Pg.632]

While the sharp-interface approach is useful for conceptualizing flow at the coast, particularly in large-scale problems, the reality is more complex. Not only does the saline groundwater flow but also a zone of intermediate salinity extends between the fresh and saline end members, establishing what many refer to as a subterranean estuary . Like their surface water counterparts, these zones are hotbeds of chemical reactions. Because the water in the interface zone ultimately discharges into coastal waters, the flow and chemical dynamics within the zone are critically important to understand. Research into these issues has only just begun. [Pg.467]

The magnitude of chemical fluxes carried by SGD is influenced by biogeochemical processes occurring in the subterranean estuary, defined as the mixing zone between groundwater and seawater in a coastal... [Pg.471]

Figure 8 (a) Scientists extruding a sediment core taken through the subterranean estuary of Waquoit Bay, MA. Note the presence of iron oxides within the sediments at the bottom of the core (orange-stained sediments in foreground), (b) Changes in iron and phosphate concentration with depth in three sediment cores similar to the one shown in (a). The red circles indicate Fe concentration (ppm pg Fe/g dry sediment) while the blue diamonds represent P (ppm pg P/g dry sediment). Error bars indicate the standard deviation for triplicate leaches performed on a selected number of samples. The dashed lines represent the concentration of Fe and P in off-site quartz sand. Also shown is the approximate color stratigraphy for each core. The ff value for Fe vs. P in cores 2, 3, and 5 is 0.80, 0.91, and 0.16, respectively. [Pg.472]

In a study of the Waquoit Bay subterranean estuary, a large accumulation of iron (hydr)oxide-coated sediments within the fresh-saline interface was encountered. These iron-oxide-rich sands could act as a geochemical barrier by retaining and accumulating certain dissolved chemical species carried to the subterranean estuary by groundwater and/or coastal seawater. Significant accumulation of phosphorus in the iron oxide zones of the Waquoit cores exemplifies this process (Figure 8). [Pg.473]

Phosphorous is not the only nutrient that can be retained/removed via reactions in the subterranean estuary. The microbial reduction of nitrate to inert dinitrogen gas, a process known as denitrification, is known to occur in the redox gradients associated with fresh and saline groundwater mixing. Conversely, ammonium, which is more soluble in saline environments, may be released within the subterranean estuary s mixing zone. While the overall importance of SGD on the global cycle of certain chemical species remains to be seen, there is little doubt that SGD is important at the local scale both within the United States and throughout the world. [Pg.473]

Charette MA and Sholkovitz ER (2002) Oxidative precipitation of groundwater-derived ferrous iron in the subterranean estuary of a coastal bay. Geophysical Research Letters 29 1444. [Pg.473]

Charette MA and Sholkovitz ER (2006) Trace element cycling in a subterranean estuary. Part 2 Geochemistry of the pore water. Geochimica et Cosmochimica Acta 70 811-826. [Pg.473]

Moore WS (1999) The subterranean estuary A reaction zone of ground water and sea water. Marine Chemistry 65 111-125. [Pg.474]


See other pages where Subterranean estuary is mentioned: [Pg.359]    [Pg.594]    [Pg.604]    [Pg.264]    [Pg.264]    [Pg.40]    [Pg.503]    [Pg.471]    [Pg.473]   
See also in sourсe #XX -- [ Pg.264 ]




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