HYDROCLIMATOLOGY AND BIOGEOCHEMISTRY OF THE AMAZON .1. EROSION

The Amazon is the largest stream in the world. Its basin covers at lea st 7 . 10(6) km2, which represents approximately 5% of the global cont inental area and almost 70% of the area of the continents localized in the equatorial zone, between 5-degrees-S and 5-degrees-N of latitude. The global tropical moist forest covers approximately 9.35 . 10(6) km 2, so that the Brazilian evergreen rain forest represents at least 50% of this area. At Obidos, the most accessible downstream station for c ollecting data, the area concerned is 4.619.10(6) km2. The purpose of these two extended abstracts is to show how changes and oscillations o f climate can significantly affect erosion as well as carbon and nitro gen cycles, and may also mask the degradations of the environment due to deforestation.