Human Impact on Ecosystems
Acid Rain
Acid rain, or acid deposition refers to the fall of acids from the atmosphere in two forms, wet and dry.
Wet Deposition
•Wet deposition includes acidic rain, snow, and fog, which affect plants, animals, and soil depending on factors like acidity and soil composition.
Dry Deposition
Dry deposition involves acidic gases and particles, which settle on surfaces such as buildings, cars, and trees, and can be washed away by rain, making the runoff even more acidic. These acids are carried by winds over long distances, crossing state and national borders.
Primary Cause of Acid Rain
•The primary causes of acid rain are sulfur dioxide (SO2) and nitrogen oxides (NOx), mostly from fossil fuel- burning power plants. In the atmosphere, these gases react with water and chemicals to form sulfuric and nitric acids, a process accelerated by sunlight.
Greenhouse Effect
Energy from the sun drives the earth's weather and climate, and heats the earth's surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy. Without this natural "greenhouse effect" life as known today would not exist, due to the lack of heat. Thanks to greenhouse gases, the earths average temperature is a more hospitable 60°F. The most important gases are carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons.
Deforestation
the removal of trees in a region it can be caused by himans and natural processes.
Desertification
The process in which a region becomes arid. It is primarily driven by climate change in the real world.
Erosion
The wearing away of land or soil by the action of wind water or ice. Soil erosion is a natural process. it becomes a problem when human activity causes it to occur much faster than under natural conditions.
Causes of Soil Erosion
Wind and water are the main agents of soil erosion. The amount of soil they can carry away is influenced by two related factors - Speed and Plant Cover (plants protect the soil, and in their absence, wind and water can do more damage).
Importance of Plants (Multi.)
Plants provide protective cover on the land and prevent soil erosion for the following reasons:
Plants slow down water as it flows over the land (runoff) and this allows much of the rain to soak into the ground;
• Plant roots hold the soil in position and prevent it from being washed away;
• Plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode;
• Plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind the soil, thus preventing erosion.
The loss of protective vegetation through deforestation, over-grazing, ploughing, and fire makes soil vulnerable to being swept away by wind and water.
In addition, over-cultivation and compaction cause the soil to lose its structure and cohesion and it becomes more easily eroded. Erosion will remove the top-soil first. Once this nutrient-rich layer of soil is gone, few plants will grow in the soll again.
Without soll and plants the land becomes desert-like and unable to support life. This process is called desertification. It is very difticult-often impossible, in fact- to restore desertified land.
Preventing Soil Erosion
The use of contour ploughing and wind breake:
Leaving ungloughed grass strips between ploughed land:
Allowing indigenous planta to graw along the river bank instead of plowing and planting crops right up to the water's edge:
Encounging biological diversily by planting different types of plants together;
Conservation of wetlands.
The loss of protective vegetation through deforestation, over-grazing, ploughing, and fire makes soil vulnerable to being swept away by wind and water.