HYDROELECTRIC DAMS IN THE AMAZON

The implementation of hydroelectric dams in the Amazon replaces extensive terra firme forests with flooded areas. In these areas, seasonal variation in water level periodically floods the adjacent forests. In this paper, we present how this flooding alters the service that upland forests in the Amazon play to the carbon (C) cycle. How does this happen? In the period when the reservoir fills, the forests produce three times more leaves, reduce the foliar content of nutrients and the decomposition of organic matter is much slower. In spite of this, curiously, flooding increases the input of nutrients and does not favor the accumulation of litter and nutrients on the soil. The soil becomes more acidic, with lower C contents and higher N availability, after flooding. However, the accumulated effect of flooding cycles, since the creation of the hydroelectric dam, reduces soil acidity and increases losses of C and N. Thus, forests are no longer sinks but emitters of C to the atmosphere. Why does this happen? Throughout the book, we will discuss the mechanisms and processes that explain the impacts of this flooding on forest biogeochemistry.

Autorentext

Guilherme is a professor at UFRR. He develops teaching and research activities with Education, Environmental Management and Tropical Forest Soil Ecology. Marcos is a professor at UFRRJ. He has published over 400 articles in journals and more than 50 chapters and books on Pedology, Soil Organic Matter, Nutrient Cycling and Soil Use and Management.