Interstitial-water profiles

Rapid increases in the interstitial water concentrations of dissolved strontium with increasing burial depth of deep-sea carbonate sediments have been interpreted as evidence of the recrystallization reaction (Baker et al., 1982 Elderfield et al., 1982 Gieskes, 1983). Figure 8.17 shows an example of interstitial-water profiles of dissolved alkaline-earth species from a carbonate nanno-fossil ooze from the Ontong Java Plateau (DSDP site 288 5°58 S, 161°50 E). At this site calcium and magnesium concentrations are linearly correlated, and their gradients are governed by chemical reactions deep in the sediment column. 

Figure 8.25. Some chemical and diagenetic properties of organic-rich marine sediments as a function of depth based on DSDP interstitial water profiles. A. Schematic gradients of SO42-, total alkalinity, Ca2+ and Mg2+ in pore waters, and zones of sulfate reduction, methanogenesis and fermentation. Magnesium diffuses into the sediment and organogenic dolomite forms at depth. B. Logarithm of calculated saturation states of interstitial waters with respect to dolomite. Dolomite saturation=0. All these pore waters are oversaturated with respect to dolomite. (After Compton, 1988.)...

Figure 5.5 Time series of interstitial water profiles at an intertidal site in the Wash (UK), near to the major riverine discharge, after the tide has ebbed. The inventory of nitrate in the interstitial water decreases with time due to rapid denitrification. The interstitial water profiles are collected using an in-situ sipping system consisting of porous probes inserted at fixed depths in the sediment from which water samples are removed by applying a vacuum. Samples are preserved using mercuric chloride and returned to the laboratory for colorimetric analysis.

Fig. 5.2.3. Vertical profiles of total SPC in interstitial water found at stations with different exposition grade to non-treated wastewater effluent, 0.1 km (B) and 3 km (C).

Fig. 5.2.4. Vertical profiles of nitrate and sulfate concentrations in interstitial water, and total LAS and SPC concentrations in sediment (wet weight) for station C. (Figure taken...

Fig. 6.5.4. Vertical profiles of LAS in sediment and interstitial waters from three stations situated at different distances from the non-treated wastewater effluent point (A 12 km B 0.1 km and C 3 km (taken from Ref. [34])).

From the foregoing discussion, it will be appreciated that sediments constitute the final natural compartment for reception of LAS that have not been degraded. The vertical profiles of the concentrations of the LAS homologues in the sediment and interstitial water found for three sampling stations are shown in Fig. 6.5.4. There is a pronounced decrease in LAS concentration with depth, particularly in the first few centimetres, which may be related to greater discharges of effluent into... 

For stations B and C, where the LAS concentrations were higher than for A, the variation in total LAS concentration with sediment depth was determined by the homologues of 12 and 13 carbon atoms (Fig. 6.5.4). These homologues present a strong tendency to sorption and are readily biodegradable. In interstitial water, the vertical profile of the LAS concentration is similar to that observed for the sediment, particularly at stations B and C. The homologue-specific partition coefficient did not vary much with depth, because there is no appreciable variation in the composition of the sediment with depth [34]. 

Figure 8.17. Interstitial water chemistry of sediments at DSDP site 288. A. Ca2+ and Mg2+ concentration-depth profiles. B. Sr2+ concentration-depth profile. C. Sr/Ca ratio in carbonates black dots, observed pluses calculated from interstitial water data and distribution coefficients. Lithology 1A, pyrite-bearing, foram-nanno ooze IB, bioturbated nanno ooze 1C, nanno-foram chalks and oozes. (After Gieskes, 1983.)...

Anthropogenic inputs to intertidal environments are often direct, through point-source waste disposal, but they are also indirect, from riverine, marine and/or atmospheric sources. Trace metals are partitioned between each component of the intertidal sediment-water system they are found in solution ( bulk water or interstitial water) and associated with suspended and deposited sediments. This chapter is concerned with the biogeochemistry of trace metals in deposited intertidal sediments. Two main sections follow in the first, an overview of surface sediments and sediment depth profiles is presented, and in the second, a case study is given of the historic record of Zn from saltmarsh sediments in the Severn Estuary, UK. 

FIGURE 2.15 Saturation profile when a chemical solution is injected in a reservoir at interstitial water saturation. 

FIGURE 2.17 Water saturation profile showing interstitial water displaced by injected water. 

FIGURE 2.19 Saturation profile for polymer flood started at interstitial water saturation when... 

McDuff, R.E. Gieskes, J.M. (1976) Calcium and magnesium profiles in DSDP interstitial waters diffusion or reaction arr/i planet. Sci. Lett., 33, 1-10. 

Fig. 5.31. Vertical profiles of sulfide (-2 valence) in off-reef sediment interstitial waters in the water region of the Nansha Islands, South China Sea (Song and Li, 1996b). (a), (b), (c), and (d) illuminated the vertical distribution of-2 valence sulfur in the water sample from 94-8, 94-12, 94-16, and 94-23 stations respectively. The solid and dashed lines represented the ES(—II) and HS respectively...

The examination of the sulfur isotope variation in the different species and oxidative states reveals very interesting behavior (Fig. 2). This figure should be examined in relation to Fig. 3 that presents the values versus S/C atomic ratio. Following the interstitial water sulfate isotope profile with depth into the core shows that the supply of sea water is open for the lake (top) and through the sand barrier seepage (bottom). This keeps the values close to open sea... 

Some results on using HA in marine chemical investigations are reported. The new modifications of reversed flow-injection manifolds for the determination of dissolved silicate, phosphate, sulfate, sulfide, and manganese(II) in seawater samples and normal flow-injection methods for the determination of total alkalinity, sulfate, and main nutrient-type constituents in interstitial water samples are described. The use of the proposed procedures for obtaining the concentration profiles of some important species in seawater and in interstitial water of marine sediments is shovm. The advantages of FIA techniques for determining the chemical data in a chemical laboratory are demonstrated. 

Fig. 28. Interstitial liquid velocity profile and normalized velocity profile [data by Yamagoshi (Y2)], Dy = 25 cm, Uc = 5.2 cm/sec, air-water system at room conditions. Atfjusted Mo and m are 45 and 26 cm/sec, respectively.

When bulk fluid flow is present (v 0), concentration profiles can be predicted from Equation 10-17, subject to the same boundary and initial conditions. This set of equations has been used to describe concentration profiles during micro-infusion of drugs into the brain [33]. In addition to Equation 10-17, conservation equations for water are needed to determine the variation of fluid velocity in the radial direction. Relative concentrations are predicted by assuming that the brain behaves as a porous medium (i.e., velocity is related to pressure gradient by Darcy s law, see Equation 6-9). Water introduced into the brain can expand the interstitial space this effect is balanced by the flow of water in the radial direction away from the infusion source and, to a lesser extent, by the movement of water across the capillary wall. 

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