Blackwater rivers

The Temi River samples had the largest aromatic carbon content because of inclusion of the humic acid fraction. Tropical blackwater rivers are known to contain large percentages (as much as 30%) of humic acid DOM because of the low-conductivity waters and lack of solubility controls associated with the sandy podzols in the tropical rain forest (24, 25). 

Edwards, R. T., J. L. Meyer, and S. E. G. Findlay. 1990. The relative contribution of benthic and suspended bacteria to system biomass, production, and metabolism in a low-gradient blackwater river. Journal of the North American Benthological Society 6 241-250. 

Sabater, F., J. L. Meyer, and R. T. Edwards. 1993. Longitudinal patterns of dissolved organic carbon concentration and suspended bacterial density along a blackwater river. Biogeochemistry 21 73-93. 

Janzen, D.H. (1974) Tropical blackwater rivers, animals, and mast fruiting by the Dipterocarpaceae. Biotropica 6, 69-103. 

Many deciduous and coniferous trees contain varying levels of phenolics, including tannins. Blackwater rivers in forested areas of the world, such as the Amazon basin or the southern United States, carry phenolics (tannins) leached out of trees. Such rivers differ in plant and animal life from whitewater rivers. ... 

Although originally developed for research purposes on soil and coal-derived HAs (Blom et al., 1957 Brooks and StemheU, 1957 Schnitzer and Gupta, 1965), indirect titration methods were also applied to aquatic samples in the 1970s. For example. Beck et al. (1974) analyzed 10 unfractionated DOM samples from a blackwater river in southeastern Georgia (USA), and Weber and Wilson (1975) analyzed three FAs from a darkly colored river and pond in New Hampshire (USA). It was later recognized (Sposito and Holtzclaw, 1979 Perdue et al., 1980) that incomplete removal of a humic substance from a Ca(CH3C02)2 reaction mixrnre causes carboxyl content to be overestimated. Davis (1982) found that incomplete removal of a humic substance from a Ba(OH)2 reaction mixture causes total acidity to be underestimated. The critical nature of the filtration step in indirect titrations was further discussed by Perdue (1985). 

Variation among Sampling Sites. Dissolved humic substance samples from seven end-member environments were isolated for study. Autochthonous inputs to DOM were expected to dominate in Big Soda Lake and in Island Lake, which is a groundwater-sustained eutrophic lake in the sandhills of western Nebraska. Allochthonous inputs to DOM from a swamp environment predominate in the Suwannee River. They also dominate in the Calcasieu River in western Louisiana, but the proportion of swampland is much lower there. The Temi River is a tropical blackwater tributary of the Orinoco River in Venezuela, where allochthonous inputs dominate. The entire Sagavanirktok River basin is located north of the tree line on the North Slope of Alaska a mixture of allochthonous and autochthonous inputs was expected for the various rivers and lakes in this basin. Lastly, Hidden Lake Creek, which is the outlet of Hidden Lake on the Kenai Peninsula of Alaska, was sampled to determine if nutrient inputs from decaying salmon were contributing to primary production and autochthonous inputs to DOM. 

Fulvic and humic acid from Temi River, blackwater tributary of Orinoco River, Venezuela 0.820 HOD—solvent peak interferes 0.250 0.250 1.00 47.7... 

Battin, T.J. (1998) Dissolved organic matter and its optical properties in blackwater tributary of the upper Orinoco River, Venezuela. Qrg. Geochem. 28, 561-569. 

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