BIOLOGY ECOLOGY

BIRTH OF A RIVER

Tectonic plates shifted millions of years ago

BIRTH OF A RIVER

As tectonic plates shifted millions of years ago, the Andes rose, transforming South Americas drainage basins The east-flowing Amazon River that we know today took shape 10.5 million years ago. The river and its tributaries now flow through three major types of forest. In two of them, igapo and vårzea, the rivers can be divided into three types: black. clear, and white.

BLACK WATER

Acidic and low in nutrients, these waters are stained dark by decomposing plants

CLEAR WATER
These rivers are low in sediments because they drain ancient shields of rock.

WHITE WATER
Nutrient-rich sediments flow from the Andes. clouding these rivers.

WATER AND NUTRIENT CYCLE
In all three types of forest

1. Leaves in the canopy catch raindrops, helping to protect the soil from erosion

2. Rainwater drips off leaves and trickles down branches, then sinks into the soil.

3. Water as well as nutrients from decomposed leaves are absorbed by roots adn sent up into branches and leaves.

4. Leaves transpire, releasing water vapor into the atmosphere. The cycle begins again.

RAIN FOREST CIRCULATION
Much of Amazonias water stays in Amazonia. Winds from the east blow moist ocean air over the forest, and plant transpiration circulates more than half the rainfall back into the atmosphere—a cycle that repeats four or five times, moving from the Atlantic to the Andes. A shrinking forest threatens to interrupt this cycle.

WITH THE INSIDE TRACK ON THE NEW, THE OLD, THE OFF-THE-BEATEN TRACK AND THE OUT-OF-THIS-WORLD, YOU WON'T AND A MORE KNOWLEDGEABLE TEAM OF DESTINATION SPECIALISTS.