Environmental balance

Environmental balance refers to the ways of recycling matter and the flow of energy within an ecosystem in order to ensure continuous supply or availability.

Environmental balance is achieved through the following processes or ways:

1. Hydrological (water) cycle
2. Carbon cycle

• Mineral nutrient cycle.

1. Nitrogen cycle
2. Food chain and food web

• Hydrological (water) cycle

1. This is the natural exchange or circulation of water between the oceans, the atmosphere and the land
2. The atmosphere receives water through:
3. Evaporation from ocean, rivers and from land
4. transpiration form plants,
5. breathing or respiration by plants and animals.

1. the land receives water
2. rainfall from atmosphere
3. infiltration and percolation
4. the ocean receives water through:
5. rainfall from the atmosphere
6. streams and rivers
7. run-off

Importance of Water Cycle or Hydrological Cycle and Interdependence

1. water is an important agent of weathering of rocks
2. water helps to dissolve plant nutrients in solutions for easy absorption by plants

• water is also required by plants for photosynthesis

1. all living organism require water for normal life processes
2. transpiration by plants aids cooling of the plants

• Carbon Cycle

Carbon cycle involves the series of processes which contributes to the circulation of carbon in nature.  Carbon is circulated in form of carbon dioxide

Loss of carbon from the air

1. Carbon dioxide is removed from the air during photosynthesis as green plants use it to manufacture their food
2. Carbon is also lost in form of carbonates of calcium and magnesium through leaching and drainage

Gain of Carbon in the air:  The atmosphere gains carbon dioxide through:

1. Burning of fuel like coal, wood and petrol
2. The action of volcanoes which release carbon dioxide

• Through respiration by plants and animals

1. The dead, decaying and putrefaction of plants and animals.

Importance of Carbon Cycle (carbon cycle and interdependence)

1. Carbon cycle provides carbon dioxide which is an important gas in the atmosphere
2. Plants depend on carbon dioxide for photosynthesis

• Carbon dioxide trapped in the leaves with the presence of sunlight is used to manufacture food

1. Animals, therefore, depend on plants either directly or indirectly for their food
2. Animals take in oxygen and release carbon dioxide to the atmosphere
3. Plants absorb carbon dioxide and release oxygen during photosynthesis.

• Nitrogen Cycle
• Nitrogen cycle involves the complex process by which nitrogen is circulated between the atmosphere, soil plants and animals
• Plants can only use nitrogen in form of nitrate.

Soil and plants gain nitrogen through

• Symbiotic nitrogen fixation: Through the root nodules of leguminous plants with the aid of some bacteria
• Electrical discharge: When oxygen combines with nitrogen in the atmosphere to form nitrate during lightning.
• Non-symbiotic nitrogen fixation: With the aid of some bacteria, nitrogen is fixed aerobically or an aerobically into the soil.

• Ammonification and nitrification: Ammonification involves the conversion of dead and decaying organic matter into ammonium compounds while nitrification converts the ammonium compound first into nitrite and finally into nitrate with the aid of some bacteria
• Application of organic manure and nitrogen fertilizers: these add nitrogen into the soil

Loss of Nitrate from the Soil

• Denitrification: This is the major way by which nitrate in the soil is lost by its conversion to  gaseous nitrogen with the aid of some denitrifying bacteria
• Other methods include leaching, erosion, soil Ph, crop removal, etc.

Importance of Nitrogen Cycle (nitrogen cycle and interdependence)

• It provides nitrogen which is an important gas in the atmosphere
• It provides nitrate which is the main source of protein synthesis in plants
• Nitrate is used to produce proteins for animals
• It also provides food for micro-organisms in the root nodules of legumes
• The bacteria in turn decompose plants and animals tor release nutrients when they die.

• Mineral Nutrient Cycle
• This refers to the circulation of mineral nutrients between plants and the soil
• These mineral nutrients include calcium, iron, sulphur, zinc, sodium, phosphorus and potassium.

Mineral Nutrient Cycle and Interdependence

1. Plants absorb these nutrients from the soil for growth and production
2. When plants die, they decay and the nutrients are returned to the soil

• The decomposition and release of nutrient are aided by micro-organisms in the soil.

FOOD CHAIN TROPHIC LEVEL AND FOOD WEB

Definition:  Food chain is defined as the linkage of a series of organism in a habitat through the flow of energy of consumer levels and their nutritional sequence.  In other words, food chain involves energy transfer in which each organism feeds on the one before it in a sequence.  Examples of food chain areas follows:

1. Grass ® sheep ® main
2. Grass ® grasshopper ® toad ® snake ® hawk

• Diatoms ® euglena ® water fleas ® tilapia

The first in each group is usually called autotroph (or producer) e.g. grass, while the next e.g. sheep is called the primary consumer while the last e.g. man is called the secondary consumer.

Trophic level

Trophic level refers to the feeding stages found in a food chain, e.g.

Grass ® grasshopper ® toad ® snake  ® hawk

The above food chain has five trophic levels.

Food web

Definition:  Food web is a complex feeding relationship of organism made up of many interrelated food chains.  It involves a wider range of energy transfer.  The food web in fig. 50.4 contains five different food chains

ENVIROMENTAL INTERVENTIONS

Meaning:   Environmental intervention refers to the forces of nature and the activities of man that alter the natural existence of the components of the ecosystem

Types of Environmental intervention

There are two types of interventions in our environment.  These are natural and human interventions.

• Natural interventions: natural intervention is caused by a number of natural processes which include:

1. Desert encroachment
2. Sea level changes

• Tectonic movement

1. Volcanism
2. Earthquakes
3. Climatic changes

• Drought
• Hurricane

1. Flooding

The effects of these Natural intervention include:

1. New features different from those initially there are produced e.g. volcanism creates volcanic mountains
2. Changes in the landscape of the area e.g. earthquake will result in digging trenches and gullies where it was not initially present.

• Raising and lowering of beaches

1. Widespread destruction or extinction of aquatic life e.g. drought results in drying up the water and this will lead to the extinction of water animals
2. Displacement of animals
3. Displacement of man.

• Human intervention: Man has interfered with the ecosystem through many of his activities.  This human (man) intervention include the following:

1. Deforestation
2. Pollution

• Mining/quarrying

1. Cloud seeding
2. Hunting
3. Urbanization

• Land reclamation
• Farming activities, e.g. burning

1. Construction
2. Fishing
3. Industrialization

• Grazing

Some of these interventions are now discussed in detail.

• Deforestation

1. Deforestation causes increased runoff and flooding
2. It leads to destruction of natural habitat

• It leads to changes in energy balance

1. It leads to erosion and reduction in rainfall.

• Land reclamation

1. It leads to less rainfall
2. It changes the drainage pattern

• It reduces the amount of soil moisture content

1. It leads to loss of some organism and plants

• Pollution (soil, water, atmospheric and noise)

1. Atmospheric and water pollution destroy plants and animals
2. Oil spillage and water polluting alter the type of plant that can grow in an area

• Land pollution exposes the soil surface

1. It leads to changes in the chemical composition of the soil, e.g. chemicals used in agricultural practises such as fertilizer
2. It can also lead to reduction in agricultural land.

• Grazing

1. Overgrazing leads to reduction in agricultural land
2. It depletes the vegetative cover of the soil

• It leads to soil compaction through excessive trampling by animals

1. It destroys the soil structure and causes soil erosion

• Farming activities e.g. Burning

1. It causes the destruction of weeds
2. It burns the organic matter content of the soil

• It causes the destruction of pest and natural habitat

1. Some may be harmful to man
2. It can also lead to soil erosion

• Mining

1. Mining causes pollution of the land
2. Ti causes the reduction of farm lands

• It leads to pollution of surface and underground water

1. It also leads to disintegration of settlement

• Urbanization

1. It causes reduction in agricultural land
2. Wastes produced can cause pollution

• It can lead to loss of some organism and plants

1. It exposes the soil to erosion and flooding

• Construction

1. It destroys the soil structure
2. It can cause soil erosion

• It can also kill plants and animals

Some wastes produced can cause