Identifying some human activities that disrupt the cycles in an ecosystem and infer the harmful effects of certain activities on bigger or more complex ecosystem.
Cycles in nature such as the water cycle, the oxygen-carbon dioxide cycle and the nutrient cycles are important for the survival of an ecosystem. When these cycles are disrupted, the organisms in the ecosystem are affected.
Human beings use the things in their environment to live comfortably. They build towns and cities and roads to connect them. They farm the land to produce different crops. They build factories to manufacture the many things that they need. They travel by land, water and air to seek better opportunities.
In doing different activities, human beings make use of the things found on the environment such as trees, fuels and metals.
Human activities produce much waste which pollutes the environment. Pollution is an unfavorable change in the environment. It affects both living and nonliving things in an ecosystem.
Improper disposal of waste from homes, hospitals, stores and factories causes garbage to pile up. Open dump sites destroy the beauty of a place. They also provide breeding places for rats and flies, which are harmful to people.
Topsoil is an important part of the land. When farmers use too much inorganic fertilizers, the soil loses some of its nutrients that are needed by plants. This is because the fertilizers limit the ability of decomposers to breakdown waste in the soil. Pesticides sprayed on plants do not decompose easily. They may even kill people and animals that eat the plants.
Mining operations contaminate the soil with poison from metal ores. When land is polluted, the nutrient cycle may be disrupted.
Pollution to water is harmful to plant and animal life. Take for example life in a pond ecosystem where plants and algae are the producers. Some fish eat algae. Some big fish eat the smaller fish.
Many people use detergent for washing clothes. When laundry water is drained into pond, the water becomes polluted. The polluted waster contains phosphorus and nitrogen which are nutrients needed by plants and algae in making food. These producers will grow fast until they cover the whole pond. When the nutrients are all used up, the plants will die. As decomposers feed on the dead plants, they use up much oxygen in the water, so the fish has less oxygen to use. When the oxygen in the water is used up, the fish will die. Eventually, the pond will also die.
Sewage water may contaminate drinking water supplies. Contaminated water can make people and animals sick.
Leachate is liquid runoff from dumpsites that seeps into the groundwater. Leachate may have contaminants such as lead. Chemical and oil spills in seas and oceans can kill water birds and other water animals.
Burning of fuels releases more carbon dioxide into the air than the forests can recycle. Too much carbon dioxide in the air traps heat which otherwise should escape to space. Then heat cannot escape, air becomes warm. This is called greenhouse effect. The rising of temperatures can cause a change in climates. When the climate becomes warm, the ice caps in the polar region would melt and cause flooding of coastal communities in many countries.
The gases released by some industries and motor vehicles contain chemicals that make rainwater acidic. Acid rain kills plants and animals on the land. It can kill plants and animals in water. Acid rain can also damage buildings and statues.