Carbon dissolution

A big concern in swimming pools is prevention of etching and scaling (ie, precipitation of CaCO ) which can be controlled by maintenance of a proper degree of saturation with respect to calcium carbonate. The calcium carbonate dissolution-precipitation equiUbrium is represented by ... 

Jonge, V. N. de and Villerius, L. A. (1989). Possible role of carbonate dissolution in estuarine phosphate dynamics. Limnol. Oceanogr. 34, 332-340. 

Murray RW, Knowlton C, Leinen M, Mix AC, Polsky CH (2000) Export production and carbonate dissolution in the central equatorial Pacific Ocean over the past 1 Myr. Paleoceanography 15(6) 570-592... 

Figure 4.1. Removal of carbonate from Israeli arid soils as indicated by the X-ray diffractograms after extraction of the carbonate fraction by NaOAc-HOAc solutions at various pHs for 16 hours. C calcite d = 3.04 A, and D dolomite, d = 2.89 A. Number 1, 2, 3, 4, 5, and 6 indicate non-treated soil (No. 1), treatments (No. 2-6) with NaOAc-HOAc solutions at pH 7.0, 6.0, 5.5, 5.0 and 4.0, respectively (after Han and Banin, 1995. Reprinted from Commun Soil Sci Plant Anal, 26, Han and Banin A., Selective sequential dissolution techniques for trace metals in arid-zone soils The carbonate dissolution step, p 563, Copyright (1995), with permission from Taylor Francis US)...

Figure 4.2. Dissolution of Ca from Israeli arid soils by NaOAc-HOAc solutions at various pHs after the extraction of the exchangeable fraction (after Han and Banin, 1995. Reprinted from Commun Soil Sci Plant Anal, 26, Han and Banin A., Selective sequential dissolution techniques for trace metals in arid-zone soils The carbonate dissolution step, p 568, Copyright (1995), with permission from Taylor Francis US)...

Calcium can be used as an indicator for selective carbonate dissolution. Its concentration in the extracts is limited either by its content in the carbonate phase (at low pHs and/or low carbonate content of the soil) or by the acid capacity of the extracting solution (at higher pHs and/or higher carbonate content in the soil). The interplay of these factors is clearly shown in Fig. 4.2. 

In summary, sodium acetate buffer solutions at pH 5.5 and at the soil to solution ratio of 1 25 only extract the carbonate from calcareous soils with 10-20% of carbonate, and, at pH 5.0, all of the carbonate from soils with 30-50% of carbonate is dissolved. A second extraction with a fresh buffer solution is required for soils with more than 50% carbonate. The dissolution kinetics of carbonate showed that six hours of extraction are generally sufficient for complete carbonate dissolution. The part of the carbonate fraction not dissolved at the carbonate fraction step is mainly... 

Han F.X., Banin A. Selective sequential dissolution techniques for trace metals in arid-zone soils The carbonate dissolution step, Commun Soil Sci Plant Anal 1995 26 ... 

Like the climate system described in Chapter 7, this diagenetic system consists of a chain of identical reservoirs that are coupled only to adjacent reservoirs. Elements of the sleq array are nonzero close to the diagonal only. Unnecessary work can be avoided and computational speed increased by limiting the calculation to the nonzero elements. The climate system, however, has only one dependent variable, temperature, to be calculated in each reservoir. The band of nonzero elements in the sleq array is only three elements wide, corresponding to the connection between temperatures in the reservoir being calculated and in the two adjacent reservoirs. The diagenetic system here contains two dependent variables, total dissolved carbon and calcium ions, in each reservoir. The species are coupled to one another in each reservoir by carbonate dissolution and its dependence on the saturation state. They also are coupled by diffusion to their own concentrations in adjacent reservoirs. The method of solution that I shall develop in this section can be applied to any number of interacting species in a one-dimensional chain of identical reservoirs. 

Keywords Carbonate dissolution, Dissolved flux, Dissolved load, Ebro River basin, Evaporite dissolution, Long-term fluxes... 

Dissolved Fluxes from Evaporite and Carbonate Dissolution. 115... 

The estimation of the carbonate and evaporite weathering rate requires the quantification of the elements originating from the two components. Roy et al. [10] calculated the carbonate weathering rate (TDS originating from carbonate dissolution) as follows ... 

A new direction in searching for the atmospheric CO2 sink considering the joint action of carbonate dissolution, global water cycle and the photosynthetic uptake of die by aquatic organisms... 

ABSTRACT The locations, magnitudes, variations and mechanisms responsible for the atmospheric C02 sink are uncertain and under debate. Previous studies concentrated mainly on oceans, and soil and terrestrial vegetation as sinks. Here, we show that there is an important C02 sink in carbonate dissolution, the global water cycle and photosynthetic uptake of DIC by aquatic ecosystems. The sink constitutes up to 0.82 Pg C/a 0.24 Pg C/a is delivered to oceans via rivers and 0.22 Pg C/a by meteoric precipitation, 0.12 Pg C/a is returned to the atmosphere, and 0.23 Pg C/a is stored in the continental aquatic ecosystem. The net sink could be as much as 0.70 Pg C/a, may increase with intensification of the global water cycle, increase in C02 and carbonate dust in atmosphere, reforestation/afforestation, and with fertilization of aquatic ecosystems. Under the projection of global warming for the year 2100, it is estimated that this C02 sink may increase by 22%, or about 0.18 Pg c/a. 

KEYWORDS atmospheric CO2 Sink, carbonate dissolution, global water cycle, aquatic photosynthesis, organic matter storage/burial... 

Previous studies addressed oceans and terrestrial vegetation as C02 sinks. Here, we describe an important C02 sink in carbonate dissolution, the global water cycle (GWC), and uptake of dissolved inorganic carbon (DIC) by aquatic. The sink is larger than previous estimates (Meybeck 1993 Gombert 2002). 

This paper presents an estimate of the C02 sink by carbonate dissolution, GWC and photosynthetic uptake of DIC by aquatic ecosystems, and suggests a new direction in balancing the global C budget. 

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