Limnological variables and macrophyte infestation in Tucuruı´ reservoir - Para´ - Brazil

This paper identified the relationship between aquatic macrophyte infestation and some limnological variables in Tucuruı´ reservoir, a hydroelectric power facility in Para´ State, northern Brazil. The spread of macrophyte stands jeopardizes environmental quality in many aspects since it is a natural habitat for the malaria vector; it is also an area of increased methane emission. On top of that, macrophyte infestation can also be a major problem for navigation and energy production. Thematic Mapper images and geoprocessing techniques were used to map the area occupied by macrophyte stands in 1988 and 1994. Seventeen aquatic compartments inside the reservoir were used as test areas. It was observed that, in general, there was a decrease in macrophyte infestation except for some aquatic compartments. Limnological variables were then measured at the different compartments and analyzed. The results have shown that compartments with higher values of phosphorus and electrical conductivity displayed a slower de-infestation process.