Sustainability, Agriculture, and Eutrophication

What is sustainability?

Responsible maintenance of ecosystems to ensure long-term viability

What determines sustainable harvesting?

Harvest rate must be lower than replacement rate

Why are Finnish forests considered sustainably managed?

Forest law requires regeneration after logging

Why is overfishing a sustainability issue?

It has caused rapid declines in fish populations such as cod

What physical factors affect agricultural sustainability?

Soil erosion, leaching, fertilisers, carbon footprint, and monocultures

How does soil erosion reduce sustainability?

It reduces soil quality through tillage

Why are fertilisers needed in agriculture?

Crops deplete nutrients over time

How can fertilisers cause environmental harm?

Excess nutrients leach into water causing eutrophication

What is leaching?

Loss of soil nutrients due to water runoff

How does agriculture increase carbon footprint?

Use of machinery, transport, heating, and fossil fuels

Why are monocultures unsustainable?

They increase pest problems and chemical pollution

What is eutrophication?

Excessive nutrient enrichment of water

Which nutrients cause eutrophication?

Nitrates and phosphates

What is an algal bloom?

Rapid growth of algae due to nutrient enrichment

Why are algal blooms harmful?

They block sunlight and reduce oxygen levels

How does decomposition worsen eutrophication?

Bacterial respiration depletes dissolved oxygen

Can eutrophication occur naturally?

Yes, through gradual drying and sediment accumulation

What is biological oxygen demand (BOD)?

The oxygen required to decompose organic material

What does a high BOD indicate?

High pollution and microbial activity

How is BOD measured?

By measuring oxygen loss over 5 days in dark conditions at 20°C