Acre River BAsin (67º - 71º W, 09º - 11º S, Acre - , Brazil) í ecologic aspects : limnology, physiography and climate

Abstract

The physical and chemical water quality of Acre River and some of its marginal lakes were studied. Some climatic and physiographic characteristics of the area between Rio Branco City (Acre State) and Lua Nova Town (Amazonas State) are also presented. Samplings took place through one year, 1984-1985, at irregular frequency. Some parameters were measured monthly: air and water temperature, which ranged between 22.0 and 33.0^oC (air) and 23.0 and 30.5°C (water). Small differences occurred between the rainy and dry seasons. The water transparency ranged from 0.1 to 0.4 m; the oxygen saturation, 49 to 137%; pH, 4.5 to 6.7, and electrical conductivity, from 26 to 76 µS/cm. Other parameters were measured on1y in September, October, and December 1984: color ranged from 35 to 160 mg/L Pt; ammonia from 0.20 to 1.02 mg/L N-NH₄; nitrite up to 4 µg/L N-NO₂; nitrate up to 0.80 mg/L N-NO₃; silica from 1.5 to 5.6 g/L Si-SiO₂, total dissolved orthophosphate 18 to 38 µg/L P-P0₄, and total dissolved iron up to 2.44 mg/L. These introductory can be used as an approach for future and deeper investigations in the basin.