What is a biome? It isn’t a term that is used everyday for most of us and explaining its meaning is the best place to begin.
A biome is describes a large area containing certain types of plants and animals. How these plants and animals interact with climate, soil types, and the amount of water available, the geology of the landscape and whether it is north or south on the globe defines each biome.
What are terrestrial biomes?
The following is the current accepted list of terrestrial biomes.
- Taiga/Boreal Forests
- Temperate Coniferous Forests
- Temperate Broadleaf and Mixed forests
- Temperate Grasslands, Savannahs and Shrublands
- Montane Grasslands and Shrublands
- Deserts and Xeric Shrublands
- Mediterranean Forests, Woodlands and Scrub
- Tropical and Sub-Tropical Grasslands, Savannahs and Shrublands
- Flooded Grasslands and Savannahs
- Tropical and Sub-Tropical Moist Broadleaf Forests
- Tropical and Sub-Tropical Dry Broadleaf Forests
- Tropical and Sub-Tropical Coniferous Forests
If we take the desert and tropical moist broadleaf biomes as examples, this is how they are individually defined.
Desert Biome – An area that has less than ten inches of rainfall per year and what water there is has a very high evaporation rate. A desert biome can be hot or cold but will always have poor soil quality. There will also be very few animals, birds or insects, and those that do live in a desert biome are more likely to be nocturnal creatures. Desert biomes also tend to have very little plant life.
Tropical Broadleaf biome – Better known to most of us as the tropical rainforest, this is almost completely opposed to a desert biome. A rainforest biome is defined by:-
Monthly temperatures average above 64F and there is usually rainfall in excess of 100 inches per year.
Three layers (labeled A, B and C) of trees. The A layer consists of widely spaced trees of 100 feet and above in height and displaying ‘umbrella’ canopies. Layer B tends to have closed canopy trees that are around 8o feet in height. Layer C contains the smaller trees, 60 feet in height and they also have closed canopies. Below these three layers come the shrubs and saplings and that leaves ground level with very little growth due to the light being unable to penetrate the canopies above.
Soil depends on the age of the area. Older biomes tend to have less fertile soil because of the constant drain on its resources, whereas younger (volcanic) tropical soils might be very fertile.
Tropical biome fauna tends to be very diverse. They are likely to be brightly colored or patterned, have loud calls, be adapted to life in the trees and rely greatly on a fruit diet.
For much more information about terrestrial biomes, try this link.
Moving on to aquatic biomes, now that we have the general idea of what a biome is and how it works. Aquatic biomes are divided into:-
- Freshwater Biomes
- Marine Biomes
Freshwater biomes are subdivided into:-
- Ponds and Lakes
- Streams and rivers
Marine biomes are subdivided into:-
- Coral reefs
Freshwater biomes are usually defined by the water having less than 1 salt concentration. Creatures and plants that live in freshwater biomes cannot usually survive in marine biomes. Marine biomes cover three fourths of the surface of our planet. Much of our oxygen supply comes from the algae found in marine biomes and they also cleanse our atmosphere of carbon dioxide.
Wonderful explanation of the complexities of our ocean biomes can be found here, along with details of both marine and freshwater biomes.
The details of terrestrial and aquatic biomes are vast and those provided here only scratch the surface and give a basic understanding of biomes and their definitions. For much more information and a description of all the terrestrial biomes, try this site.