Saturation state causes

These three numerical experiments show how the waters of an evaporating lagoon respond differently to the different seasonal perturbations that might affect them. Some record of these perturbations might, in principle, be preserved in the carbonate sediments precipitated in the lagoon. All three perturbations—productivity, temperature, and evaporation rate— cause seasonal fluctuations in the saturation state of the water and in the rate of carbonate precipitation. Temperature oscillations have little effect on the carbon isotopes. Although seasonally varying evaporation rates affect 14C, they have little effect on 13C. Productivity fluctuations affect both of the carbon isotopes. 

Two principal factors drive reaction in the evaporating fluid. First, the loss of solvent concentrates the species in solution, causing the saturation states of many minerals to increase. The precipitation of amorphous silica, for example,... 

Supersaturated a solution containing more solute than is present in its saturated state Surface Tension property of liquid causing it to contract to the smallest possible area due to the unbalance of forces at the surface of the liquid... 

As we have demonstrated, IEX reactions occur independent of the saturation state of the aqueous solution, raise the local solution pH, and so cause additional glass dissolution via reaction (6). The residual rate for alkali-rich glass compositions, therefore, is simply the net rate of glass dissolution controlled by the rate at which the ion-exchange reaction proceeds. 

A major contribution of this paper was pointing out the importance of bioturbation and bioirrigation on chemical processes associated with carbonate dissolution. In the movement of sulfidic sediment from depth to near the interface by biological processes, oxidation of the sediment produces sulfuric acid which ends up titrating alkalinity, lowering pH, and thus lowers saturation state (e.g., Berner and Westrich, 1985). Actually this process is very complex, involving many reactive intermediate compounds such as sulfite, thiosulfate, polythionates, etc. Aller and Rude (1988) demonstrated an additional complication to this process. Mn oxides may oxidize iron sulfides by a bacterial pathway that causes the saturation state of the solution to rise with respect to carbonate minerals, rather than decrease as is the case when oxidation takes place with oxygen. 

This relationship can be modified to calculate (equation 7.5) the commonly used concept of the number (N) of pore volumes of water necessary to cause a given change in porosity (< >). If an ion activity product of 0.4, a change in saturation state... 

Many studies of the impact of chemical diagenesis on the carbonate chemistry of anoxic sediments have focused primarily on the fact that sulfate reduction results in the production of alkalinity, which can cause precipitation of carbonate minerals (see previous discussion). However, during the early stages of sulfate reduction (—2-35%), this reaction may not cause precipitation, but dissolution of carbonate minerals, because the impact of a lower pH is greater than that of increased alkalinity (Figure 4). Carbonate ion activity decreases rapidly as it is titrated by CO2 from organic matter decomposition leading to a decrease in pore-water saturation state. This process is evident in data for the Fe-poor, shallow-water carbonate sediments of Morse et al. (1985) from the Bahamas and has been confirmed in studies by Walter and Burton (1990), Walter et al. (1993), and Ku et al. (1999) for Florida Bay, Tribble (1990) in Checker Reef, Oahu, and Wollast and Mackenzie (unpublished data) for Bermuda sediments. 

HCl gas dissolves in it to cause a sudden partial decrease in atmospheric pressure and the partial temperature may fall to some extent. This causes the condensation of water vapour in the saturated state to form another mist which absorbs the HCl gas again. This phenomenon spreads wider and wider in the damp air and creates a large volume of dense smoke. It is observed that the smoke is not created at the flame, but at a distance from the flame where the burnt gas and the air mix well together. 

Another important effect, which has been outlined in Chapter 6.2, is the ageing, or better the respiratory enrichment in CO of the deep waters along the flow path from the North Atlantic to the North Pacific causing large differences in saturation state above the seafloor in the Atlantic and the Pacific (Fig. 9.6). 

In considered model (la), the fluorescence saturation is caused by a finite lifetime r and by intercombination conversion. In model (lb), due to the finite fluorescence lifetime and due to the saturation of the energy transfer chaimels. Let us note that the model (lb) could be also supplemented with the intersystem crossing mechanisms, but paehmtnaiy expieiiments showed that at the given parameters of the laser radiation the process for albumins and mRFPl is small compared to the mechanisms under study and contributes little to fluorescence saturation. Therefore, this mechanism has been excluded to increase the stability of the inverse problem solution (details and mathematical basement of inverse problem solution of nonlinear laser fluorimetry can be found elsewhere (Boychuk at al., 2000). For the same reason the induced processes from the excited states (two-photon absorption or photoizomerization, etc) have been excluded. 

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