Alkaline lake

Yuretich, R.F. and Cerling, T.E. 1983 Hydrogeochemistry of Lake Turkana, Kenya mass balance and mineral reactions in an alkaline lake. Geochimica et Cosmochimica Acta 47 1099-1109. 

To model the chemical effects of evaporation, we construct a reaction path in which H2O is removed from a solution, thereby progressively concentrating the solutes. We also must account in the model for the exchange of gases such as CO2 and O2 between fluid and atmosphere. In this chapter we construct simulations of this sort, modeling the chemical evolution of water from saline alkaline lakes and the reactions that occur as seawater evaporates to desiccation. 

Garrels and Mackenzie wanted to test whether simple evaporation of groundwater discharging from the mountains, which is the product of the reaction of rainwater and CO2 with igneous rocks, could produce the water compositions found in the saline alkaline lakes of the adjacent California desert. They began with the mean of... 

They made several assumptions about which minerals could precipitate from the fluid. The alkaline lakes tend to be supersaturated with respect to each of the silica polymorphs (quartz, tridymite, and so on) except amorphous silica, so they suppressed each of the other silica minerals. They assumed that... 

The reactions consume H+, driving the fluid toward alkaline pH, as shown in Figure 24.2. This effect explains the alkalinity of saline alkaline lakes. 

Figure 24.3 compares the calculated composition of the evaporated water, concentrated 100-fold and 1000-fold, with analyses of waters from six saline alkaline lakes (compiled by Garrels and Mackenzie, 1967). The field for the modeled water overlaps that for the analyzed waters, except that Ca++ and Mg++ are more depleted in the model than in the lake waters. This discrepancy might be explained if in nature the calcite and sepiolite begin to precipitate but remain supersaturated in the fluid. 

In a second example, we consider the changing chemistry of Mono Lake, a saline alkaline lake that occupies a closed desert basin in California, USA, and why... 

Blum et al. (1998) isolated a bacterial strain Bacillus arsenicoselenatis from muds of Mono Lake, ahypersaline alkaline lake in northern California (see Section 24.2). Under anaerobic conditions in saline water, over an optimum pH range of 8.5-10, the strain can respire using As(V), or arsenate, as the electron acceptor, reducing it to As(III), arsenite. 

The experiments also indicate that WD may be an important mechanism for producing I/S at low temperatures in nature by a transformation mechanism (56). The percentage of illite layers formed by this mechanism is proportional to the number of WD cycles, and to the layer charge of the original smectite. Simple K-exchange does not produce stable illite layers in smectite therefore, these layers probably form by WD prior to deposition in subaqueous environments. The exception is found in high pH environments where illite layers may form without WD by chemical reaction, as has been reported previously for alkaline lakes (64, 65). 

Simpson HJ, Trier RM, Li YH, et al. 1984. Field experiment determinations of distribution coefficients of actinide elements in alkaline lake environments. NucI Waste Geochem, 326-342. 

In order to be successful in finding a biocatalyst that is adapted to the required process conditions, one could sample at a site where similar conditions apply. As such sampling sites with low biodiversity, but high selection pressure such as hypersaline ponds, acidic or alkaline lakes, deserts, hot springs or sites polluted with chemicals are particularly useful. 

Mariner, R. H. Surdam, R. C. 1970. Alkalinity and formation of zeolites in saline alkaline lakes. Science, 170, 977-980. 

Analogous mechanistic studies of the formation of zeolite minerals have been reported. Kossowskaya (51), in this volume, considers the genetic associations of sedimentary zeolites and the dominant factors controlling their process of formation. An especially lucid and concise presentation of the mechanism of formation of sedimentary zeolites under low temperature conditions is given by Mariner and Surdam (52). In studies on the formation of zeolites in saline alkaline lakes, they show differential... 

Mono, Big Soda, Walker, Crowley, and Searles desert alkaline lakes ... 

Finkelstein, D.B., Munhall, A., Pratt, L.M. and Bauer, C.E. (2004) A baseline study of evaporative water chemistry and microbial mat diversity from alkaline lakes in Warner Valley, Oregon. Abstracts with Programs. The Geological Society of America, 36(5), 87. 

Ames et al. (1958) hot springs alteration of zeolite in alkaline lake, Hector, Calif., U.S.A. analyst S.S. Goldrich. 

The material from the Hector area of California is believed to have formed by the action of hot spring waters containing Li and F on clinoptiolite. The Mg was obtained from the alkaline lake waters (Ames and Goldich, 1958). The material from Morocco is associated with marls and is believed to be authigenic. These two types of trioctahedral smectite appear to be the only ones with a relatively pure Si tetrahedral sheet. No analyses were found which indicated tetrahedral Al values between 0.02 and 0.30. Analyses of saponite indicate there is complete isomorphous substitution between the range Si3.70 Al0.3o and Si3.0s Al0.92 (Table XXXIX). Caillere and Henin (1951) reported an analysis of a fibrous expanded clay (diabantite) which had a tetrahedral composition of Si3.i7 Alo.49 Fe3+0.34. There is some question as to whether this should be classified as a smectite regardless, it indicates the possibility of Fe3+ substitution in the tetrahedral sheets of the trioctahedral 2 1 clays. 

Cultivations are usually carried out in submerged cultures in bioreactors. Fungi can be cultivated on solid wastes such as straw. In those countries which have enough land and1 sun, and in regions where naturally alkaline lakes are present, SCP from photoautotrophically grown algae could be economically feasible. 

Thompson, J. B. Ferris, F. G. (1990). Cyanobacterial precipitation of gypsum, calcite and magnesite from natural alkaline lake water. Geology, 18, 995-8. 

Zeolites created in shallow sea sediments are also widespread. Other marine zeolites include analcime, merlinoite, chabazite, stilbite, and more rarely, erionite, mordenite, and laumontite. Figure 13 shows a schematic of the zoning patterns of autogenic zeolites and feldspars in tuffs of saline alkaline lakes, saline alkaline soils, deep-sea sediments, open hydrologic systems and burial diagenesis... 

Cerhng T. E. (1996) Pore water chemistry of an alkaline lake Lake Turkana. In The Limnology, Climatology, and Paleoclimatology of the East African Lakes (eds. T. C. Johnson and E. O. Odada). Gordon and Breach, Amsterdam, pp. 225-240. 

Gosselin D. C., Sibray S., and Ayers J. (1994) Geochemistry of K-rich alkaline lakes, Western Sandhills, Nebraska, USA. Geochim. Cosmochim. Acta 5%, 1403-1418. 

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