8.5 Eutrophication

• Hypoxia in eutrophic water is caused by the decomposition of dead algae, which consumes large amounts of oxygen.
• Agricultural runoff introduces nitrogen and phosphorus into water bodies, primarily from fertilizers and animal waste
• Match the cause of eutrophication with its description:

  Agricultural runoff ↔️ Fertilizers and animal waste wash into water

  Industrial discharge ↔️ Factories release waste into rivers

  Urban wastewater ↔️ Sewage systems release waste into water

  Atmospheric deposition ↔️ Nitrogen oxides from air pollution
• Eutrophication leads to the creation of "dead zones" in aquatic ecosystems.
• Algal blooms in eutrophic water disrupt food chains by blocking sunlight
• Cyanobacteria in algal blooms can produce toxins harmful to humans.
• Human activities contribute to eutrophication through nutrient pollution.
• Match the human activity with its description:

  Agricultural runoff ↔️ Fertilizers and animal waste enter water

  Industrial discharge ↔️ Factories release nutrient-rich waste

  Urban wastewater ↔️ Sewage systems release phosphorus

  Atmospheric deposition ↔️ Nitrogen oxides from air pollution
• Human activities contribute to eutrophication through nutrient pollution, primarily from agricultural runoff, industrial discharge, urban wastewater, and atmospheric deposition
• Which key nutrients are associated with agricultural runoff in eutrophication?

  $N$ and $P$
• Fertilizers and animal waste from agricultural runoff release nitrogen and phosphorus into water bodies.
• Atmospheric deposition contributes nitrogen oxides from pollution into water bodies.
• Match the human activity with its description and key nutrients:

  Agricultural Runoff ↔️ Fertilizers and animal waste, $N$ and $P$

  Industrial Discharge ↔️ Nutrient-rich waste, $N$ and $P$

  Urban Wastewater ↔️ Sewage release, $N$ and $P$

  Atmospheric Deposition ↔️ Nitrogen oxides from pollution, $NO_{x}$
• What are the primary consequences of increased nutrient levels in water bodies due to human activities?

  Excessive algal growth
• Nutrient management reduces runoff and nutrient leaching by improving fertilizer application and livestock waste disposal.
• Upgrading sewage treatment plants to remove nutrients before discharge is a key strategy for preventing nutrient loading from urban sources.
• Order the effects of eutrophication in aquatic ecosystems:

  1️⃣ Over-enrichment of nutrients

  2️⃣ Algal blooms

  3️⃣ Oxygen depletion

  4️⃣ Ecosystem changes
• What conditions are created in water bodies due to oxygen depletion from decaying algae?

  Hypoxic conditions
• Riparian buffers along water bodies filter runoff and stabilize soil to reduce nutrient pollution.
• Restoration techniques such as dredging sediment and aerating water aim to improve water quality and restore ecosystem balance.
• Match the case study with its affected region and key challenges:

  Chesapeake Bay ↔️ Eastern U.S., agricultural and urban runoff

  Baltic Sea ↔️ Northern Europe, agricultural runoff and industrial discharge
• What key nutrients are highlighted in both the Chesapeake Bay and Baltic Sea case studies as major contributors to eutrophication?

  $N$ and $P$
• Eutrophication is the process where water bodies become overly enriched with nutrients
• Agricultural runoff is a primary cause of eutrophication.
• Algal blooms in eutrophic water block sunlight
• Hypoxia occurs in eutrophic water due to oxygen depletion.
• Toxicity in eutrophic water is often caused by cyanobacteria
• Oxygen is released during photosynthesis but consumed during decomposition in eutrophic water.
• Agricultural runoff carries fertilizers and animal waste containing nitrogen and phosphorus
• Excess nitrogen and phosphorus are major contributors to algal blooms.
• Eutrophication is primarily caused by excess nitrogen and phosphorus
• Order the consequences of eutrophication:

  1️⃣ Algal blooms

  2️⃣ Oxygen depletion

  3️⃣ Loss of biodiversity

  4️⃣ Toxicity from cyanobacteria

  5️⃣ Impaired water quality
• Toxicity in eutrophic water is only harmful to aquatic organisms.

  False
• Agricultural runoff is a major cause of eutrophication, leading to algal blooms.
• Match the cause of eutrophication with its consequence:

  Agricultural runoff ↔️ Algal blooms

  Industrial discharge ↔️ Oxygen depletion

  Urban wastewater ↔️ Loss of biodiversity

  Atmospheric deposition ↔️ Toxicity from cyanobacteria