Effects of humans on the ecosystem

An ecosystem is a self-contained, dynamic system made of a population of species in its physical environment.  Humans threaten ecosystems by producing waste, damaging habitats and removing too many species without giving the ecosystem time to naturally regenerate.

 

Deforestation

 

  • Due to increase in human population over the last 300 years, a great deal of natural woodland has been destroyed.
  • Deforestation is the permanent destruction of forests in order to make the land available for other uses.
  • The world’s rainforests are being destroyed at a rate of 78 million acres per year, resulting in vegetation degradation, nutrient imbalance, flooding and animal displacement.
  • Trees also act as a natural air filter in the carbon cycle by taking in carbon dioxide and releasing oxygen, so deforestation contributes to global warming.
  • Some estimates indicate that canopy forest species will be reduced by 35 percent by 2040 if deforestation continues at the same rate.

 

The threat of deforestation

 

  1. Loss of biodiversity

The loss of biodiversity is one consequence of deforestation. Deforestation has also caused the extinction of various species of flowers and animals. The other species are also fading too because of the loss of their habitat. Aside from the loss of genetic resources, there is also the loss of herbs that are used for making medicines. Flooding as well as soil erosion is two of the effects caused by deforestation.

 

  1. The effect on Climate

Deforestation also bears significant links to climate change. Under normal circumstances, forests help stabilize the climate by removing carbon dioxide from the atmosphere. Trees require carbon dioxide to manufacture carbohydrates, which feed the trees and contribute to tree structure, and, indirectly, to produce oxygen. Without trees to take up excess carbon dioxide, it builds up in the atmosphere and traps solar radiation, leading to an overall warming of the planet and extreme temperature and weather shifts. The changes in weather and climate can lead to natural disasters such as droughts, crop failures, melting of ice caps, flooding and desertification.

  1. Loss of soil solubility

 

  1. The loss of humus in the soil

Humus is the soil glue without which our rivers run brown and dust storms strip our thin veil of precious top soil. Humus provides the single most efficient storage of water, minerals and carbon and it is this trio that will most impact soil health. Humus usually increases the ability of the soil to resist erosion.

  1. The loss of protection

The problem of soil erosion is a direct corollary of deforestation as deforestation makes the soil more exposed to wind and water, which ultimately results in soil erosion. Moreover heavy rainfall has a much more adverse effect than it did before deforestation took place for starters, heavy rainfall causes the water, on areas with slopes, to carry with it large proportions of silt and limestone. As there are no trees to support the soil, the run-off of the land surface has a great tendency to cause floods.

  1. The effect on local population

Deforestation is usually motivated by financial gain. Those who benefit may live outside the country where the deforestation is occurring. Many local residents lose their homes and see their culture destroyed along with the trees. These people find it difficult to adapt to new life style.

 

 

Pollution

 

Pollution is the contamination, harm, or disruption of the natural environment through the emissions of harmful substances. Pollution is most typically associated with anthropogenic sources but can also occur from natural activity, such as volcanic eruptions. Pollution can impact air, water, and land. Pollutants include domestic, industrial, and agricultural waste.

Air pollution

 

Any undesirable change in physical, chemical, and biological character of air, which affects the living organisms, is called air pollution 

 

  1. Air pollution carbon dioxide and methane
  • Accumulation of these gases leads to global warming
  • Methane (CH4) the main source of methane pollution is agriculture. But smaller amounts of methane can also be released during waste combustion and natural gas extraction. Methane is a greenhouse gas that contributes to thegreenhouse effect and ozone loss.
    Carbon monoxide (CO) consists during incomplete combustion of fuels. When we let a car engine run in a closed room, carbon monoxide concentrations in the air will rise extensively. Carbon monoxide contributes to the greenhouse effect, smog and acidification.
  • The level of these gases are increasing in the atmosphere mainly due to increased activities by humans, like deforestation, burning of fossil fuels, raising livestock, coal mining etc.
  • Due to this increase in carbon dioxide and methane, it absorbs more radiation, leading to increase in the earth’s temperature. This is known as global warming.

 

What are the effects due to enhanced global warming?

  • Global warming leads a lot of harmful effects to the environment.
  • Increased in water vapour in atmosphere. Water vapour enhances global warming as it is green house gas which absorbs more infrared than carbon dioxide and methane.
  • Melting of polar ice caps leading to sea level rise, flooding and droughts.
  • Changes in weather pattern.

 

 

  1. Air pollution by acidic gases (sulphur dioxide and oxides of nitrogen)

 

  • Sulphur dioxide contaminant is mainly emitted during the combustion of sulphur containing fossil fuels, such as crude oil and coal.
  • Sulphur dioxide concentrations in air have decreased in the past two decades, mainly because we use more non-sulphur-containing fuels for the generation of energy.
  • Sulphur dioxide is a stinging gas and as a result it can cause breathing problems with humans.
  • These gases dissolve in water forming sulphuric acid and nitric acid in rain clouds.
  • The acidic rain falls to earth as a dilute solution of sulphuric and nitric acid. This is known as acid rain.

 

 

Effects of acid rain

 

  • The acid rain can turn the calcium carbonate to calcium sulfate. The calcium sulfate can crumble and be washed away.
  • It kills the leaves of some species of plants.
  • When in atmosphere, sulfur dioxide and nitrogen oxide gases and their particulate matter derivatives like sulfates and nitrates, degrades visibility and can cause accidents, leading to injuries and deaths.

 

 

Water pollution

 

Water pollution is the pollution or contamination of natural water bodies due to inflow or deposition of pollutants directly or indirectly into water systems. Water pollution very often caused by human activities.

 

  1. Water pollution by sewage
    • Sewage pollutants include domestic and hospital wastes, animal and human excreta.
    • Sewage can result in eutrophication in a similar way to overuse of fertilizers. This is because sewage contains high levels of nutrients such as phosphates, organic matter and bacteria.
    • The phosphates act as fertilizers for algae, while the bacteria feed on the organic matter and reproduce rapidly, using up O2 in respiration.
    • If sewage is untreated before disposal it can lead to disease organismssuch as cholera and typhoid being transmitted in the water.

 

  1. Water pollution by nitrogen-containing fertilizers

 

  • Fertilizers enter into water bodies due to the excess use of fertilizers for framing, in nearby rivers and water bodies.
  • Soil erosion, which is causes mineral salts to leach way into water bodies.
  • Sewage can result in eutrophication in a similar way to overuse of fertilizers. This is because sewage contains high levels of nutrients such as phosphates, organic matter and bacteria.
  • The phosphates act as fertilizers for algae, while the bacteria feed on the organic matterand reproduce rapidly, using up O2 in respiration.
  • If sewage is untreated before disposal it can lead to disease organismssuch as cholera and typhoid being transmitted in the water and also to cancer of the stomach.
  1. Water pollution by inorganic waste.
  • Household detergents discharged into river often contain phosphate ions. Theses encourage growth of water plants, leading to possible eutrophication.
  • Industrial waste such as mercury and copper are highly toxic to all organisms. They affect the nervous system and cause highly paralysis.

 

  1. Pollution due to insecticides
  • Insecticides re non-bio degradable substances and may get washed into the water bodies.
  • Hence, insecticides accumulate in the bodies of the organisms.
  • They are passed long food chains to increasing concentration in the bodies of organisms from one trophic level to another.
  • As a result, the consumers at the end of the food chain will accumulate high level of insecticides that can pose serious toxic effects on their body. This is called bio-accumulation.