Brian LeBlanc, Sheffield, Ron | 1/29/2009 2:56:50 AM
The environment is the world in which we live, both the living (biotic) and the non-living (abiotic). The biotic includes all the living things (plants and animals) on and in the ground, water and air. The abiotic part of the environment includes the non-living part of the soil and rock, water, air and the climate around us. The living and non-living parts of the environment are inter-related and interactive.
The abiotic factors including climate can determine what types of plants and animals can live in an area and how many can live there at any given time. The plants and animals can affect the physical environment around them. This local interrelationship of physical and living factors forms a local ecosystem. An ecosystem may be quite small or may extend over large areas. The plants and animals living around a small spring in a desert would form a small ecosystem. The interrelated large ecosystems making up the desert would form a biome.
The physical environment can determine the types and numbers of plants and animals that can live in a particular place. There are fewer plants and animals per unit of area in a desert than in a rainforest. This all starts with the difference in the available water to support plant growth and animal survival. Temperature, wind, elevation, soil type and fertility and length of seasons all can play a controlling role in what grows or lives.
Living things also can affect the local physical environment. Trees interrupt and reduce wind speed, protecting soil and animals, reducing moisture loss and slowing change in temperature. Trees, grasses and other plants protect soil from erosion and help hold and absorb water into the soil. Plants can break up rocks, beginning the conversion into soil. The switch from using wood to using charcoal for cooking in the Middle East started the conversion of Lebanon and the surrounding area from a lush, forested area to an arid near-desert. The famed “Cedars of Lebanon” were cut and made into charcoal, and the goat herds ate the re-growth. Without the forests, the water cycle from transpiration was gone and rainfall decreased and became less reliable.
Man also is capable of changing the environment on a global scale. It is now clear that burning fossil fuels (coal, oil and gas) has increased the amount of carbon dioxide and other “greenhouse gases” in the atmosphere to the point that the temperature of the earth is increasing. The impacts of this are now being seen in melting of glaciers and the ice at the poles, a rise in sea level, changes in weather patterns of rain and drought. The full impacts of this phenomenon will not be seen for years to come, but most countries now accept that action must be taken to reduce CO2 production.
On a local level, the way we live can affect our environment by polluting the air, water and land. Improperly burning waste and fuel can pollute the air, as can the release of volatile chemicals and the exhaust from cars and trucks. Improper disposal of wastes can pollute the soil and water. Disturbing the soil without proper control measures can cause topsoil to erode, destroying the productivity of the land and polluting streams with sediment. Runoff from streets and discharges from sewers, chemical plants, confined animal facilities and construction sites when not properly treated will cause water pollution, reducing water available for drinking, fish and game production, recreation and irrigation.
Humans also generate large quantities of waste from manufacturing products, processing food and raw materials as well as from living. Some of these wastes are hazardous, and some, such as waste and sewage, can be a threat to human and animal health. Many wastes contain nutrients and compounds that can reduce water quality. Safe waste disposal is a necessity to preserve our environment and our quality of life.
Rodney Hendrick, Ph.D.; Water Quality Specialist, LSU AgCenter