Lakes dissolved organic carbon

A number of freshwater lakes were surveyed for concentrations of plutonium, the ratio of its upper to lower oxidation states, pH, and the concentration of dissolved organic carbon (DOC), which are shown in Table 11(11). 

Miskimmin BM, Rudd JWM, Kelly CA. 1992. Influence of dissolved organic carbon, pH, and microbial respiration rates on mercury methylation and demethylation in lake water. Can J Fish Aquat Sci 49 17-22. 

Welsh, P.G., J.F. Skidmore, D.J. Spry, D.G. Dixon, P.V. Hodson, N.J. Hutchinson, and B.E. Hickie. 1993. Effect of pH and dissolved organic carbon on the toxicity of copper to larval fathead minnow (Pimephales promelas) in natural lake waters of low alkalinity. Canad. Jour. Fish. Aquat. Sci. 50 1356-1362. 

Abernathy and Cumbie 1977). Mercury concentrations greater than 0.5 mg/kg (but less than l.Omg/kg) FW have been reported in trout from several wilderness lakes in northern Maine (Akielaszak and Haines 1981) and from the Adirondacks region of New York (Sloan and Schofield 1983) these values are considerably higher than might be expected for fish inhabiting remote lakes. These elevated concentrations were usually associated with lakes of low pH, low calcium, low dissolved organic carbon concentrations, and low water hardness and alkalinity. 

Driscoll, C.T., V. Blette, C. Yan, C.L. Schofield, R. Munson, and J. Holsapple. 1995. The role of dissolved organic carbon in the chemistry and bioavailability of mercury in remote Adirondack lakes. Water Air Soil Pollut. 80 499-508. 

Driscoll et al. (1994) have studied the mercury species relationships among water, sediments, and fish (yellow perch) in a series of Adirondack lakes in New York state, USA. In most lakes, approximately 10% of the total mercury loading was in the form of C2HsHg+. Mercury concentrations increased as pH fell, but the best correlation was found between [dissolved Al] and [dissolved Hg] suggesting that the same factors are responsible for mobilizing both these metals. Methylmercury concentrations correlated strongly with the dissolved organic carbon content in the water. Fish muscle tissue was analyzed for mercury and showed an increase with age. However, the study was unable to resolve the question of whether the principal source of mercury to these lakes was atmospheric deposition or dissolution from bedrock due to acid rains. 

Table 2 shows the mean values of the main chemical parameters measured between 2000 and 2004. Dependent on the lake and the parameter the sample number varies between 7 and 10 (data not shown). The chemical water composition is typical for carbonate-poor mountain regions low conductivity, alkalinity and pH and small nutrient and DOC (dissolved organic carbon) concentrations. Data of DOC are not shown, they vary between 0.14 and 0.70 mg C Ortho-phosphate is always smaller than the quantification limit of 4.3 P pg and ammonia and nitrite are negligibly small compared to nitrate (data not shown). 

Figure 16.4 Observed [ 02] in water samples from some Swiss rivers (R) and lakes (L) as a function of the dissolved organic carbon (DOC) concentrations of these waters. The results apply for noontime light intensity on a clear summer day at 47.5°N (data from Haag and Hoigne, 1986).

Table II, Concentrations of Dissolved Inorganic Carbon, Dissolved C02, and Dissolved Organic Carbon in Surface Waters of Lake N2...

Lake-Water Samples. Ten lake-water samples were collected from September 1990 to May 1991. The total soluble phosphorus concentration for the concentrated samples ranged from 23.8 to 60.8 mg of P/L, and the soluble reactive phosphorus concentrations ranged from 1.0 to 18.1 mg of P/L (Table I). Dissolved organic carbon concentration values for the concentrated samples ranged from 5000 to 20,000 mg of C/L. The signal-to-noise ratios from 12-14-h runs achieved for the NMR spectra range from 3.0 to 7.0. The pH of the concentrated samples after the addition of FeEDTA fell between the values of 7.00 and 8.00. Addition of the FeEDTA increased the pH by only a few tenths of a pH unit. 

Harvestable timber was removed from the lake bed during site preparation, but the remaining forestation was left untouched except for some shoreline clearing. The lake s waters are soft (conductivity around 50 xS/cm), slightly acidic (pH 6-7), and contain abundant organic matter dissolved organic carbon (DOC) is 2-5 mg/L. 

Ujiie et al. [204] fabricated quartz chips for NCE and reported the separation of rhodamine B and sulforhodamine at 14.4 and 66.6 cm separator lengths. The buffer was 20 mM phosphate buffer at 2kV applied voltage and the separation was achieved in 70 seconds. Wakida et al. [205] reported a high throughput characterization for dissolved organic carbon in environmental waters within 2 minutes using NCE. The authors collected water samples from 10 sampling points at the Hino River that flows into Lake Biwa. Shin et al. [206] described NCE (PDMS) with fluorescence detection for analyses of atrazine. 

Sundh, I. 1991. The dissolved organic carbon released from lake phytoplankton — biochemical composition and bacterial utilization. Ph.D. Dissertation, Uppsala University, Sweden,... 

Cole, J. J., W. H. McDowell, and G. E. Likens. 1984. Sources and molecular weight of dissolved organic carbon in an oligotrophic lake. Oikos 42 1-9. 

Schindler, D. W., P. J. Curtis, S. E. Bayley, B. R. Parker, K. G. Beaty, and M. P. Stainton. 1997. Climate induced changes in the dissolved organic carbon budgets of boreal lakes. Biogeochemistry 36 9-28. 

Tranvik, L. J. 1988a. Availability of dissolved organic carbon for planktonic bacteria in oligotrophic lakes of differing humic content. Microbial Ecology 16 311-322. 

Gergel, S. E., M. G. Turner, and T. K. Kratz. 1999. Dissolved organic carbon as an indictor of the scale of watershed influence on lakes and rivers. Ecological Applications 9 1377-1390. 

Houle, D., R. Carignan, and M. Lachance. 1995. Dissolved organic carbon and sulfur in southwestern Quebec lakes Relationships with catchment and lake properties. Limnology and Oceanography 40 710-717. 

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