How human activities disturb the nutrient cycles of a tropical rainforest in Amazonia [San Carlos de Rio Negro, Venezuela]

In 1974 a project to study the nutrient cycles of natural and disturbed tropical rainforest ecosystems in Amazonia was started in San Carlos de Rio Negro, Venezuela. After a brief description of the site and the goals of the project, the interpretation of the existing data indicates that the forest and its litter contain 92 percent of the total calcium, potassium and magnesium in the ecosystem. The forest's mineral nutrition is more dependent on rainfall and internal cycling for its nutrition than on supply by the soil, and it functions with a small amount of nutrients compared to the conditions in other tropical rainforest ecosystems. Very efficient nutrient capturing and cycling mechanisms have evolved so that losses from the ecosystem are minimal. Disturbances that destroy these fragile mechanisms lead to increased nutrient losses which compromise the rate of regeneration of the forest. The fate of nutrients after disturbance is controlled by the establishment of other biological mechanisms to capture and cycle the available nutrients. A serious warning is issued about the conversion of large forested areas in Amazonia to other uses before the impact of these disturbances is properly investigated.