Pollution: Its Impact on Ecosystems 

 

What is Pollution?

Pollution occurs when harmful substances are added to the environment, causing damage to ecosystems and living organisms.

 

Types of Pollution and Their Effects

Pollution Type	Sources	Effects on Ecosystems
Water Pollution	Untreated sewage, excess fertilisers.	- Eutrophication leads to oxygen depletion. - Death of aquatic animals.
Plastic Pollution	Non-biodegradable plastics in landfills, oceans.	- Harms wildlife (e.g., ingestion, entanglement). - Breaks into microplastics that contaminate food chains.
Air Pollution	Methane (cattle farming), carbon dioxide (burning fossil fuels).	- Enhanced greenhouse effect leads to climate change. - Global warming impacts habitats and weather patterns.

 

Water Pollution: Sewage and Fertilisers

1. Untreated Sewage

   • Contains harmful bacteria and pathogens.
   • Decomposers break it down, using up oxygen in the water.
   • Fish and other organisms die due to lack of oxygen.

2. Excess Fertilisers

   • Rich in nitrates and phosphates.
   • Cause eutrophication.

 

Eutrophication: Step-by-Step Breakdown

Eutrophication occurs when water bodies are enriched with nutrients, leading to ecological damage.

1. Nutrient Overload
   • Excess nitrates from fertilisers run into rivers/lakes.
2. Producer Overgrowth
   • Algae and plants grow rapidly (algal blooms).
3. Death of Producers
   • Dense algae block sunlight, killing underwater plants.
4. Decomposition
   • Dead plants and algae decompose, using up oxygen.
5. Oxygen Depletion
   • Decomposers' respiration reduces dissolved oxygen.
6. Aquatic Life Dies
   • Fish and other organisms suffocate and die.

 

Plastic Pollution: Why It’s a Problem

• Non-biodegradable: Plastics take hundreds of years to decompose.
• Harmful to Wildlife: Animals mistake plastics for food or get trapped in them.
• Microplastics: Tiny plastic pieces enter the food chain, affecting humans too!

 

Air Pollution: Greenhouse Gases and Climate Change

Gas	Source	Impact
Methane	Cattle farming, landfill sites.	Traps heat, contributing to the enhanced greenhouse effect.
Carbon Dioxide	Burning fossil fuels (coal, oil).	Leads to global warming and habitat changes.