Tropical Rainforest Biome

The two biomes that will be examined in this essay are the tropical rainforest biome and the hot desert biome. Both biomes will be researched with reference to their climate and soil characteristics, the information gathered will be then be compared and contrasted under the two characteristics that will be examined.

1. Climate

Climate is an important characteristic of a biome as it establishes what kind of soil will develop there, in addition to what fauna and flora will be able to live in the area. Temperature and precipitation are the main impacts on the biome. The tropical rainforest biome is commonly found between the 30°N and 30°S latitudes, (between the Tropic of Cancer and the Tropic of Capricorn) covering approximately 6-7% of the

This is due to the amount of vegetation which falls from the trees and the decay on the forest floor. The majority of tropical soils have been gradually building underneath the forest floor for millions of years. During this time, deep soils formed from the underlying rock under the heavy precipitation. Soils found in the tropical rainforest biome can be up to 30 metres in depth as a result of intensive weathering. However, they suffer from being heavily leached, meaning that many nutrients and minerals are lost from the subsoil. As this leaching has being ongoing for millions of years, the soils are deprived of many nutrients which are required by the flora above the surface. Tropical soils tend to have an extremely thin top layer. This layer is usually composed of decay from the foliage and animal remains. The plants in the rainforest provide fallen leaves and branches to the forest floor which are consumed and broken down by soil organisms and are converted back into nutrients which are consumed by the flora. This is an on-going cycle which allows the flora to receive the vital nutrients they need. The topsoil is the main source of food for the flora. The zonal soil found in the tropical rainforest is mainly composed of tropical red soil (latosols). Latosols are a reddish yellow colour due to the iron oxide and aluminium oxide found in it. They tend to be infertile soils, as they are extremely low

Desert soils are light in colour. These soils are course-textured, shallow, rocky or gravely and have a good drainage system so there is no subsurface water. These soils are coarse-textured as there is little chemical weathering due to leaching. The finer dust and sand particles are blown elsewhere, leaving heavier pieces behind. These soils are dry soils, as they get little amount of precipitation, thus they do not have high amounts of organic matter. Soil formation is restricted near to the surface as any water the desert does receive, does not move through the soil. Soils in this biome, usually have little or no foliage cover, mostly due to the fact that most of it is destroyed by the strong sun’s rays. Desert soils can differ in depth, they can be deep, shallow, salty or be covered with a desert pavement, or have a cement-like horizon close to the surface. They have a B horizon, which often contains calcium carbonate, gypsum and salts. Soil organisms found here change with the climate, however they are all adapted to the dry desert conditions. Not a large amount of microorganisms live in the dry desert soils, however algae, bacteria, mosses and lichens can be seen to be able to form biological crusts on the surface. Ants, termites, reptiles and rodents live in these soils.

Desert soils can support agriculture, however in order to do so, irrigation is often transported in from other areas or from aquifers.