Mono Lake

At Mono Lake, a closed basin, alkaline, saline lake in California, the concentrations of plutonium in the water column are about two orders of magnitude higher than in Lake Michigan(12). 

In experiments where Mono Lake water was acidified to remove carbonate and bicarbonate ions and again adjusted to pH 10, more than 90 percent of the soluble plutonium moved to the sediment phase. When carbonate ion concentration was restored, the plutonium returned to solution—strong evidence of the importance of inorganic carbon to solubility in that system(13). Early studies with Lake Michigan water, which has low DOC, had also implicated bicarbonate and carbonate as stabilizing ligands for plutonium at pH 8(14). This latter research characterized the soluble species as mainly anionic in character. 

Blum J, AB Bindi, J Buzzelli, JF Stolz, RS Oremland (1998) Bacillus arsenicoselenatis sp. nov., and Bacillus selenitrificans sp. nov. two haloalkaliphiles from Mono Lake, California that respire oxyanions of selnium and dixstmc. Arch Microbiol 171 19-30. 

Oremland RS, SE Hoeft, JM Santini, N Bano, RA Hollibaugh, JT Hollibaugh (2002) Anaerobic oxidation of arsenite in Mono Lake water and by a facultative, arsenite-oxidizing chemoauthotroph strain MLHE-1. Appl Environ Microbiol 68 4795-4802. 

Thorium generally exists as a neutral hydroxide species in the oceans and is highly insoluble. Its behavior is dominated by a tendency to become incorporated in colloids and/or adhere to the surfaces of existing particles (Cochran 1992). Because ocean particles settle from the water column on the timescale of years, Th isotopes are removed rapidly and have an average residence time of = 20 years (Fig. 1). This insoluble behavior has led to the common assertion that Th is always immobile in aqueous conditions. While this is generally true in seawater, there are examples of Th being complexed as a carbonate (e.g.. Mono Lake waters, Anderson et al. 1982 Simpson et al. 1982) in which form it is soluble. 

Anderson RF, Bacon MP, Brewer PG (1982) Elevated concentrations of actinides in Mono Lake. Science 216 514-516... 

Simpson HJ, Trier RM, Toggweiler JR, Mathieu G, Deck BL, Olsen CR, Hammond DE, Fuller C, Ku TL (1982) Radionuclides in Mono Lake, California. Science 216 512-514 Smith CR, Berelson W, Demaster DJ, Dobbs FC, Hammond D, Hoover DJ, Pope RH, Stephens M (1997) Latitudinal variations in benthic processes in the abyssal equatorial Pacific control by biogenic particle flux. Deep-Sea Res Part II-Topical Studies in Oceanography 44(9-10) 2295 Smith CR, Pope RH, Demaster DJ, Magaard L (1993) Age-dependent mixing of deep-sea sediments. Geochim Cosmochim Acta 57(7) 1473-1488... 

We now consider as an example an analysis (Table 15.1) of water from Mono Lake, California. The reported alkalinity of 34 818 mg kg-1 as CaC03 is equivalent to 700 meq of acid or 350 mmol of H2SO4. Since at this pH carbonate and bicarbonate species are present in roughly equal concentrations, we can quickly estimate the total carbonate concentration to be about 30 000 mg kg-1. We take this value as a first guess and model the titration with react... 

Table 15.1. Analysis of water from Mono Lake, California, USA (James Bischoff,...

Fig. 15.4. Use of reaction modeling to derive a fluid s carbonate concentration from its titration alkalinity, as applied to an analysis of Mono Lake water. When the correct HCO3 total concentration (in this case, 25 100 mg kg-1) is set, the final pH matches the titration endpoint.

Fig. 15.5. Concentrations of species in buffer reactions that contribute to the titration alkalinity of Mono Lake water, plotted against pH.

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... 

Fig. 24.4. Saturation indices for gaylussite in Mono Lake water at 25 °C for various years between 1956 and 1988, calculated from analyses in Table 24.2 and plotted against time (top diagram) and salinity (bottom).

These calculations (Fig. 24.5) suggest that, to the extent that the analyses in Table 24.2 are representative of the wintertime lake chemistry, gaylussite has been supersaturated in Mono Lake during the winter months since sampling began. 

The saturation state of aragonite (Fig. 24.5), on the other hand, is affected little by temperature. Aragonite remains supersaturated by a factor of about ten (one log unit) over the gamut of analyses. The supersaturation probably arises from the effect of orthophosphate, present at concentrations of about 100 mg kg-1 in Mono Lake water orthophosphate is observed in the laboratory (Bischoff et al., 1993) to inhibit the precipitation of calcite and aragonite. 

Fig. 24.5. Saturation indices of gaylussite ( , ) and aragonite (o, ) calculated for Mono Lake water in various years from analyses in Table 24.2. Open symbols ( , o) represent values calculated for 0 °C and solid symbols ( , ) show those for 25 °C.

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. 

Bischoff, J. L., D. B. Herbst and R. J. Rosenbauer, 1991, Gaylussite formation at Mono Lake, California. Geochimica et Cosmochimica Acta 55, 1743-1747. 

The Effect of Owens Dry Lake on Air Quality in the Owens Valley with Implications for the Mono Lake Area... 

The data indicate that Mono Lake has the potential to become a significant source of sulfate aerosols if the lake bed areas are exposed. 

The sampling sites were chosen in order to investigate the spatial distribution of particulate pollutants in the valley. As an additional consideration, sites were selected to coincide with the major population centers in the valley in order to determine the concentration of respirable aerosols to which valley residents are exposed on a dally basis. Seven of the sampling sites were in the Owens Valley itself, and one site was in the Mono Lake area. Site 1 was located near the Bishop Airport at the National Weather Service Meteorological station. This site is about five miles east of downtown Bishop in the center of the... 

Effect of Dust Storm Episodes on the Average Weekly Aerosol Concentrations. The total and fine gravimetric mass averaged over all sites for each week, is depicted in Figure 6. The error bars for the Owens Valley curves represent the standard deviation of the mean. The errors on the Mono Lake curve represent the sampling system error of 15%. The mean weekly values do not include the three dust storm episodes sampled separately, but do include several additional dust storms. Table I lists all the dust storms reported by the sampler operators. 

Error bars are standard error of the mean. Also included for reference is the weekly mass concentration measured at the Mono Lake sampling site. Error bars are 15% measurement system error. 

OWENS LAKE MONO LAKE DEEP SPRINGS LAKE SEARLES LAKE SALINE VALLEY... 

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