Aquatic Sciences Meeting, Albuquerque 2001

SS32 Holistic Studies In Impacted Meso-Scale Basins (Science and Society Connections)

Date: Thursday, February 15, 2001, Time: 3:00:00 PM

Location: Galisteo

Balleter, M, V, USP-CENA, Piracicaba, Brazil, vicky@cena.usp.br

Krusche, A, V, USP-CENA, Piracicaba, Brazil, alex@cena.usp.br

Victoria, R, L, USP-CENA, Piracicaba, Brazil, reyna@cena.usp.br

Martinelli, L, A, USP-CENA, Piracicaba, Brazil, zebu@cena.usp.br

Bernardes, M, , USP-CENA, Piracicaba, Brazil, mbernardes@cena.usp.br

Richey, J, E, University of Washington, Seattle, USA, jrichey@u.washington.edu

Coburn, R, , University of Washington, Seattle, USA,

Mayorga, E, , University of Washington, Seattle, USA,

Aufdenkampe, A, , , University of Washington, USA,

EFFECTS OF LAND USE CHANGES IN THE BIOGEOCHEMISTRY OF TWO TROPICAL MESO-SCALE RIVERS IN BRAZIL

Rivers' biogeochemical responses to land use-cover change were tested in two tropical basins using a combination of isotope and biogeochemical tracers and GIS modeling. The Ji-Parana, which crosses one of the most developed regions in Amazonia, is characterized mainly by extensive pastural and agricultural development in its upper region. At the lower portion of the basin the river course reverts to relatively unimpacted natural forest. Preliminary data show that there are striking differences in river water chemistry between forested and non-forested reaches, and furthermore that the metabolisms of some tributaries draining larger cities are already affected by sewage. The Piracicaba river, located in the southeast region of Brazil, is a typical example of how landscape changes lead to a significant decrease in water quality and quantity. The upper part of the Piracicaba basin is dominated by pastures. Most of its three million inhabitants are concentrated in urban centers in the lower part of the basin, which is dominated by sugar-cane plantations and industries. Point source pollution, expressed as % of urbanization, was statistically identified as the best predictor for water conductivity; SO4, Cl, Na, Ca, DOC, DIC, DIN, O2 and CO2*.

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Aquatic Sciences Meeting, Albuquerque 2001

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