Conservative behavior

Hodge VF, Johaimesson KH, Stetzenbach KJ (1996) Rhenium, molybdenum, and uranium in groundwater from the southern Great Basin, USA evidence for conservative behavior. Geochim Cosmochim Acta 60 3197-3214... 

India (Borole et al. 1982) and the Forth estuary in the UK (Toole et al. 1987), nonconservative behavior of uranium was also demonstrated. In the Amazon estuary, uranium showed elevated concentrations compared to simple mixing (McKee et al. 1987). Release of uranium from bottom sediments on the shelf was suggested to be a source of dissolved (<0.4 im) uranium. However, subsequent studies in the Amazon also demonstrated that U removal (Fig. 3) occurred at salinities <12 (Swarzenski et al. 1995, Swarzenski et al. 2003). Overall, it was established that the behavior of U is highly variable examples have been found of conservative behavior as well as both additions and removal of U by interaction with sediments. 

Attitude is a predisposition to act in a certain way. It is the state of readiness that influences a person to act in a given manner (Rahman et al. 1999). Therefore, attitude surveys in agriculture could lead to a more adequate explanation and prediction of farmers economic behavior and have been used on conservation and environmentally related issues focusing on the influence of attitude variables as predictors of conservation behavior (Dimara and Skuras 1999). Dimara and Skuras (1999) concluded from their research that a significant relationship was found between behavior and the goals and intentions of farmers. This relationship is even stronger when statements on attitudes, social norms, and perceived behavioral control are included (Bergevoet et al. 2004)... 

Seawater and marine pore fluids. As discussed above, the chlorine isotopic composition of modem seawater does not vary measurably. This is not surprising in light of its long residence hme (approximately 90 million years) and its conservative behavior in the water column. In contrast, marine pore fluids have been demonstrated to vary considerably. There is also the likelihood that hydrothermal fluids may be fractionated as a result of exchange with mineral phases, as phase separation under marine hydrothermal conditions does not appear to lead to measurable fractionation (e.g., Magenheim et al. 1995). However, to date no stable-chlorine isotopic compositions of marine hydrothermal fluids have been reported in the literature. 

It is noteworthy that in this broader context of decision making, the conservative behavior of scientists who use conventions as if they were rules of nature constitutes a paradox. On the one hand, they usually demand odds overwhelmingly against the null hypothesis before concluding it is false, and therefore behave as a risk-aversive group reluctant to gamble personal and collective reputations. On the other, many behave as risk-takers and are often willing, collectively or individually, to loose major health and environmental risks upon the public. 

As demonstrated by the polynomials in the equation of state of seawater, density is not linearly related to temperature or salinity and does not exhibit conservative behavior. One of the interesting consequences of this nonconservative behavior is that an... 

In Chapter 4, we saw how conservative chemicals are used to trace the pathway and rates of water motion in the ocean. True conservative behavior is exhibited by a relatively small number of chemicals, such as the major ions and, hence, salinity. In contrast, most of the minor and trace elements display nonconservative behavior because they readily undergo chemical reactions under the environmental conditions found in seawater. The rates of these reactions are enhanced by the involvement of marine organisms, particularly microorganisms, as their enzymes serve as catalysts. Rates are also enhanced at particle interfaces for several reasons. First, microbes tend to have higher growth rates on particle surfaces. Second, the solution in direct contact with the particles tends to be highly enriched in reactants, thereby increasing reaction probabilities. Third, adsorption of solutes onto particle surfaces can create fevorable spatial orientations between reactants that also increases reaction probabilities. 

The input of terrestrial DOM via rivers and aeolian transport was discussed in Chapter 23.3. Riverine concentrations of DOC range from 2 to 20mgC/L. In contrast, little or no terrestrial DOM is detectable in seawater, leading to the cmrent consensus that most is removed close to its point of input. In some estuaries, removal is associated with flocculation reactions promoted by the large increase in ionic strength that occms when river water mixes with seawater. In other estuaries, DOC exhibits conservative behavior, leaving marine chemists with a mystery as to how and where DOC is removed. 

Biounlimited element An element whose marine distributions are controlled primarily by physical processes and are relatively uninfluenced by biogeochemical phenomena. These elements demonstrate conservative behavior. 

Conservative Chemical behavior that is controlled by physical processes. In other words, physical transport is much faster than any chemical processes that can either supply or remove the chemical. All of the major ions exhibit conservative behavior. The concentrations of conservative species are directly proportional to each other and to salinity. 

Conservative ions Ions that exhibit conservative behavior. These include the major ions in seawater. 

The pKa of 2,4-DNP is 3.94 (Schwarzenbach et al., 1988). Thus, at pH = 7.5, more than 99.99% of the chemical is present in its anionic form, and sorption can be neglected. When further assuming that 2,4-DNP does not undergo any transformation, the compound can be assumed to exhibit a conservative behavior in the aquifer. 

Although the NBS standards were collected from several sources, some tentative conclusions can be reached concerning the combustion process. Using selected elements for comparison which are of a refractory nature and would be expected to be conserved in the ash following the combustion process, it becomes apparent that other elements such as selenium and antimony are not being conserved, but rather are lost from the ash. Refractory elements selected for illustration are Eu, Hf, Sc, Ta, Tb, and La, although most other elements display the same conservative behavior. Table VI shows the concentrations of these elements in both... 

Anbar, A.D., Creaser, R.A., Papanastassiou, D.A. and Wasserburg, G.J. (1992) Rhenium in seawater confirmation of generally conservative behavior. Geochim. Cosmochim.Acta, 56, 4099-4103. 

Figure 8.8 Conservative behavior of DOM versus salinity in the Ob and Yenisei estuaries, located adjacent to the Kara Sea in the Arctic Ocean. (Modified from Kohler et al., 2003.)...

Liss, P.S. (1976) Conservative and non-conservative behavior of dissolved constituents during estuarine mixing. In Estuarine Chemistry (Burton, J.D., and Liss, P.S., eds.), pp. 93-130, Academic Press, London. 

Mantoura, R.F.C., and Woodward, E. (1983) Conservative behavior of riverine dissolved organic matter in the Severn estuary. Geochim. Cosmochim. Acta 47, 1293-1309. 

Conservative Behavior Trace Elements in River Systems... 

Some studies have reported conservative behavior during estuarine mixing. In the unpolluted Krka Esmary of Yugoslavia, Seyler and Martin (1991) observed a linear increase in total arsenic with increasing salinity, ranging from 0.13 xgL in freshwaters to 1.8 JLgL offshore. Other studies however, have observed nonconservative behavior in estuaries due to processes such as diffusion from sediment pore waters, co-precipitation with iron oxides, or anthropogenic inputs (M. O. Andreae and T. W. Andreae, 1989 Andreae et al., 1983). The flocculation of iron oxides at the freshwater-saline interface as a result of increase in pH and salinity can lead to major decrease in the arsenic flux to the oceans (Cullen and Reimer, 1989). 

Eigure 5 shows the methane concentration for cycles 1 and 7 as fimction of the ratio of pumped and injected volume, V/Vinj. The methane concentration was half of the groundwater concentration at V/Vmj = 1, and close to the final concentration at VIVmi = 2. The end concentration was 2 mg CH4/I in the first run, and 0.8 mg/1 in the 7 run due to variations in the groundwater quality. However, the concentration patterns wotc identical in both runs, and conform to a conservative substance, with a dispersivity of 0.3 m of the aquifer. The concentrations of HCOa and dissolved organic carbon also showed conservative behavior, which indicates that injected water did not react with sedimentary organic carbon. 

The iron concentrations during pumping in the first and seventh run are shown in Figure 8. Again, the end-concentration in groundwater fluctuated and was 6 and 5.2 mg Fe /1 for run 1 and 7, respectively. In the first run, a retardation of approximately 2.5 with respect to conservative behavior is indicated in Figure 8, which is close to what was calculated by hand before. The increased retardation in subsequent runs can be modeled if the sorption sites amount to 1.4 mol sites per mol Fe. This is quite high, Dzombak and Morel (1990) proposed 0.2 mol sites per mol ferrihydrite. Of course, the latter number is valid for laboratory conditions where the oxides are... 

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