The hot and humid conditions make tropical rainforests an ideal
environment for bacteria and other microorganisms. Because these
organisms remain active throughout the year, they quickly decompose
matter on the forest floor. In other biomes, such as the deciduous
forest, the decomposition of leaf litter adds nutrients to the soil. But
in the tropical rainforest, plants grow so fast that they rapidly
consume the nutrients from the decomposed leaf litter. As a result, most
of the nutrients are contained in the trees and other plants rather
than in the soil. Most nutrients that are absorbed into the soil are
leached out by the abundant rainfall, which leaves the soil infertile
and acidic.
The tropical rainforest is a hot, moist biome found near Earth's
equator. The world's largest tropical rainforests are in South America,
Africa, and Southeast Asia. Tropical rainforests receive from 60 to 160
inches of precipitation that is fairly evenly distributed throughout the
year. The combination of constant warmth and abundant moisture makes
the tropical rainforest a suitable environment for many plants and
animals. Tropical rainforests contain the greatest biodiversity in the
world. Over 15 million species of plants and animals live within this
biome.
