Question

Natural and human activities can disrupt biogeochemical cycles and ecosystem.

Complete the following questions for either natural disruptions or human activities.

1. Name one disruption (either caused by natural disruptions or human activities).

2. Describe it.

3. Explain its impact on the geochemical cycles and ecosystem.

4. Suggest some solutions to decrease its impact.

Answer 1

Answer 1. Mining Activities by human beings. e.g Coal Mining.

Answer 2 Mining activities e.g Coal Mining have altered natural flow of biogeochemical cycles. In coal mining coal is extracted from the ground for fulfilling the energy requirements of human beings.

Coal Mining can be done by various methods:

• Surface Mining
• Strip Mining
• Contour Mining
• Underground Mining etc.

It takes millions of years to form coal by impact of heat and pressure on dead and buried plants and animals. But humans are extracting coal at much faster pace. It has its effects on biogeochemical cycles like carbon cycle (e.g Anthracite a coal is ) and ultimately on our ecosystem.

Answer 3 Impact on geochemical cycles :

Disruption in Oxygen-Carbon cycle : coal mining may lead to coal fires due to bad mining practices which may continue burning for years and decades and release fly ash, smoke, greenhouse gases and toxic chemicals.

Disruption in Sulphur cycle: Physical disturbance due to coal mining may lead to acid mine drainage. As large quantities of mineral sulphites are exposed to oxygen which oxidises sulphites to sulphates ultimately resulting in Acid Drainage.

Disruption in Phosphorus cycle: Mining in areas where rocks are rich in phosphorus minerals may lead to dust blown by wind and into nearby water bodies.

Disruption in Nitrogen cycle: mining leads to dumping of mining components, dirt etc from coal and other minerals into nearby water bodies.

  Impact on ecosystem:

• Coal Mining releases coal mine methane which is a green house gas with 20 times stronger green house potential or 20 times global warming potential.
• surface waters under impact from acid drainage explained above have pH lowered down to 3 or less. It harms the ecosystem health by causing biological damages to aquatic life e.g zooplanktons, phytoplanktons,fishes, molluscs etc.
• Washing away of phosphorus minerals leads to eutrophication in nearby water bodies that decreases dissolved oxygen available for aquatic organisms in nearby water bodies.
• Contamination of water bodies from mining components etc. also contributes to eutrophication and consequently ecosystem damages.

Answer 4 Some Solutions to decrease the impact :

1. Sustainable Mining Practices need to be adopted which cause minimum damage to ecosystem health and minimise the impact on biogeochemical cycles.It has following key areas:

• To design certain Mine site water, groundwater and seepage barriers;
• Use of Remote sensing to detect environmental impacts, subsidence and illegal mining; and
• Climate change adaptation and mining, and carbon management.

2. Following concrete steps may be taken as solutions to decrease the impact of coal mining on the geochemical cycles and ecosystem:

• Closing illegal and unregulated mines.
• Scrap mining and recycling.
• Better legislation and regulations.
• Improving environmental performance.
• Accurate tallying of toxic mining waste.
• Building from reusable waste.
• Closing and reclaiming sites of shut-down mines.
• Investing in research and development of Green Mining Technology.
• Replenishing the environment.
• Improving the efficiency of manufacturing processes.