MYP Integrated Sciences Pollution and Conservation Notes

What Is Pollution And Why Does It Matter?

1. Pollution occurs when harmful substances or energy enter the environment, disrupting chemical, physical, or biological conditions.
2. Even small changes in air, water, or soil can interfere with respiration, growth, reproduction, and food webs.

How Does Water Pollution Affect Aquatic Ecosystems?

1. Water pollution disrupts aquatic habitats when harmful substances or materials enter rivers, lakes, or oceans.
2. These pollutants interfere with feeding, respiration, reproduction, and the balance of food webs.
3. Water pollution happens through three major pathways.

Chemical contamination

1. Industrial waste, pesticides, heavy metals, and oil dissolve or disperse into water.
2. These chemicals move into organisms and enter food webs.
3. Pollutants accumulate in tissues and become more concentrated at higher trophic levels.

Eutrophication

1. Excess nitrates and phosphates enter water from fertilizers or sewage.
2. Algae grow rapidly, forming dense blooms.
3. When algae die, decomposers break them down, using large amounts of oxygen.
4. Oxygen levels fall (hypoxia).
5. Fish and invertebrates suffocate or leave.
6. The habitat collapses into a low-oxygen “dead zone.”

Microplastics

1. Microplastics (<5 mm) absorb toxic chemicals from the environment.
2. Plankton, shellfish, and fish swallow them unknowingly.
3. Microplastics block digestion and release chemicals that disrupt hormones.
4. These particles move through the food web, affecting many species.

How Does Air Pollution Affect Ecosystems?

1. Air pollution alters the chemistry of the atmosphere.
2. These changes affect plant growth, soil quality, water bodies, and entire food webs.
3. Air pollution impacts ecosystems mainly through acid rain and the greenhouse effect.

Acid rain

1. Factories and vehicles release sulfur dioxide (SO₂) and nitrogen oxides (NOₓ).
2. These gases react with water and oxygen in the atmosphere to form sulfuric and nitric acids.
3. Acid droplets fall as acid rain, lowering the pH of soil and water.
4. Acidic conditions damage organisms and disrupt nutrient cycles.
5. Effects of Acid Rain
   1. Lakes acidify, reducing fish and amphibian populations.
   2. Soil loses essential minerals, weakening plant growth.
   3. Leaves become damaged, reducing photosynthesis.
   4. Roots weaken, making plants less stable and more drought-sensitive.

Greenhouse gases and the greenhouse effect

1. The sun emits shortwave radiation that passes easily through the atmosphere.
2. Earth absorbs this energy and re-emits it as longwave infrared radiation.
3. Greenhouse gases absorb and re-radiate this longwave energy.
4. This traps heat and keeps Earth at a temperature suitable for life.
5. The key greenhouse gases are:
   1. Carbon dioxide (CO₂)
   2. Methane (CH₄)
   3. Nitrous oxide (N₂O)
   4. Water vapor
   5. Ozone

How Do Human Activities Enhance the Greenhouse Effect?

1. Burning fossil fuels increases CO₂ levels.
2. Agriculture and landfills increase methane.
3. Vehicles and fertilizers release nitrous oxide.
4. More greenhouse gases trap more heat, intensifying warming.
5. Consequences of the enhanced greenhouse effect include:
   1. Rising global temperatures
   2. More frequent heatwaves
   3. Altered rainfall patterns and drought
   4. Warmer oceans and sea-level rise
   5. Coral bleaching
   6. Species shifting their ranges
   7. More extreme weather events

How Does Land Pollution Affect Organisms and Ecosystems?

1. Land pollution introduces harmful materials into soils and terrestrial habitats.
2. These pollutants disrupt nutrient cycling, damage food webs, and reduce biodiversity.
3. Land pollution mainly occurs through plastics and solid waste and pesticides.
4. Ecological effects:
   1. Animals experience blocked digestion or starvation.
   2. Birds and mammals mistake plastics for food.
   3. Soil organisms (worms, insects, microbes) decline, reducing soil fertility.

Plastics and solid waste

1. Pesticides are chemicals designed to kill pests, but they often affect non-target organisms.
2. They harm pollinators, amphibians, insects, and soil organisms.
3. Reduced soil biodiversity slows nutrient cycling and weakens ecosystem productivity.
4. Pesticides can bioaccumulate and biomagnify through land food webs.
5. Ecological effects
   1. Fewer pollinators → reduced crop and plant reproduction.
   2. Amphibian declines due to toxin absorption through permeable skin.
   3. Soil microbes die, slowing decomposition.
   4. Predators lose food sources when insect populations collapse.

Conservation

1. Conservation protects ecosystems, species, and natural processes to preserve biodiversity and stability.
2. Definition: Conservation — protection and management to maintain biodiversity/function.

Why Do Ecosystems Need Conservation?

1. Ecosystems face threats such as habitat loss, pollution, and climate change.
2. Conservation focuses on preventing decline, not only reacting after damage occurs.

How Does Conservation Help Maintain Ecosystem Health?

1. It protects habitats, allowing species to survive and reproduce.
2. It maintains biodiversity, which strengthens ecosystem resilience.
3. It supports natural cycles like nutrient cycling and pollination.
4. It ensures resources remain available for future generations.

What Strategies Do We Use to Protect Biodiversity?

1. Conservation strategies fall into six main categories.
2. Each works by improving habitat quality, reducing threats, or restoring ecological processes.

Protected areas

1. Governments or organizations set aside land or water where human activities are restricted.
2. These areas preserve habitats, breeding sites, migration routes, and food sources.
3. Species can recover because they are not competing with human land use.

Habitat restoration

1. Damaged habitats are repaired to support biodiversity again.
2. Native vegetation is replanted, invasive species removed, and natural processes restored.
3. Restored habitats provide food, shelter, and stable microclimates.

Reforestation

1. Trees stabilize soil and reduce erosion.
2. Forests support thousands of species.
3. Trees absorb carbon dioxide, helping regulate climate.

Sustainable Resource Management

1. Resources are used at a rate that allows populations to recover.
2. This prevents long-term decline and keeps ecosystems functioning.

Laws and policies

1. Laws limit pollution, protect endangered species, and regulate land use.
2. International agreements help protect migratory species and shared ecosystems.

Community involvement

1. Local communities often manage land directly and have the strongest incentives to protect it.
2. Conservation succeeds when people help monitor species, restore habitats, and manage resources.
3. Education and involvement reduce illegal activities and increase long-term success.