REGIONAL PATTERN OF RIVERINE DISSOLVED ORGANIC-CARBON IN THE AMAZON DRAINAGE-BASIN OF BOLIVIA

Dissolved organic carbon (DOC) was analyzed at 11 hydrometric stations and 41 Andean and lowland sites in the upper Rio Madeira drainage bas in where anthropogenic alteration is low. The two regions, Andes and L lanos, behave very differently. Mean DOC is 2.2 mg liter-1 (range, 1.2 -4.2 mg liter-1) in the Andes and 5.7 mg liter-1 (range, 4.87. 4 mg li ter-1) in the Llanos. DOC enrichment may occur rapidly as Andean river s enter the Llanos. The specific DOC export is correlated with the wat ershed forested area in the Andes but not in the Llanos. Specific DOC yield for a given water runoff is 3 times higher in the Llanos. Region alization seems important for predicting DOC dynamics in such a large basin.