Atmospheric pollution in a tropical rain forest: Effects of deposition upon biosphere and hydrosphere II. Fluxes of chemicals and element budgets

Three rain forest ecosystems in the Serra do Mar, the atlantic coastal moun tain range of Brazil, have been investigated in the frame of an interdiscip linary German-Brazilian research project on dispersion, transformation and deposition of air pollutants in and around the industrial area of Cubatao. Part I of this paper gives a description of the overall goals of the projec t, the area of investigation, and the materials and methods used. It report s on the results of the field measurements conducted from 1991 to 1995, cov ering concentrations of chemicals in precipitation, soil water, surface wat er and litter fluxes. In the present paper, part II, the element fluxes are presented with calculated concentrations in the transport media (precipita tion, seepage water, litterfall) and their respective flow rates. Element b udgets for the ecosystem and for the soil compartment are interpreted with respect to turnover of chemicals, including nutrients, in forest vegetation , and to processes of soil acidification. The forests under investigation a re characterized by a very high input from the atmosphere. Between 100 and 200 kg S ha(-1) are annually carried into soil by precipitation in the form of sulfate, 20 to 70 kg of nitrogen mainly in the form of ammonium, 3 to 2 4 kg of fluoride. Input of ammonium and organic bound nitrogen is followed by nitrification in the top soil. At the most polluted site, nitrate output with seepage amounts to 300 kg N ha(-1) yr(-1), sulfate output to more tha n 400 kg S. Soil acidification associated with turnover of sulfur and nitro gen is followed by the release of aluminum from soil minerals, and leaching of ionic forms of Al (up to 280 kg Al ha(-1) annually). Transfer of alumin um ions to groundwater and surface water can have serious ecological effect s. Alkalinity is consumed, and the water is subject to acidification.