APES Unit 8.2 Human Impacts in Ecosystems

★Practice FRQ The Alaskan National Wildlife Refuge (ANWR) on Alaska’s North Slope is frequently in the news because petroleum geologists estimate that there are billions of barrels of economically recoverable oil beneath the surface of its frozen tundra. According to a 1998 United States Geological Survey (USGS) estimate, ANWR could contain up to 10 billion barrels of technically recoverable oil. Oil company officials advocate opening the refuge to oil exploration and the subsequent development of its petroleum resources. Environmentalists argue that oil exploration and development will damage this fragile ecosystem and urge Congress to protect ANWR by designating it as a wilderness area.

❖ The United States uses approximately 20 million barrels of oil per day. According to the USGS estimate, for how many days would the technically recoverable oil resource in the ANWR supply the total United States demand for oil

The ANWR would supply the US oil demand for 500 days.

Abiotic Range of Tolerances for organisms

1. pH

2. Temperature

3. Salinity

4. Sunlight

5. Nutrients (ammonia, phosphate)

• Misc: Anthropogenic pollutants

Physiological Stressors from Pollutants

• Limited Growth: Reproduction, hormonal

• Breathing: Asphyxiation

• Death

Homeostasis

The ability to experience relatively stable internal conditions in their bodies

• survive they best they can

Factors that Impact Coral Reef Species

Combo of pollutants + anthropogenic stressors

Algae have ___ tolerance and leave the reef when ___

1. Narrow

2. Temperature rises

Coral Reef Pollutants

Force algae out of reef → impacts homeostasis

• Sediments

• Pesticides

• Sunscreen

Why do Coral Reefs Lose Color when Stressed?

Vulnerable to disease w/o algae

• Coral Bleaching: increase in ATM-CO2 → hot → acidification

How do Anthropogenic Activities impact Coral Reefs?

• Greenhouse Gas Emissions → Warming → Bleaching

• Overfishing: fish die + bottom trawling breaks reef & stir up sediment

• Agri. / Urban Runoff: Sediment pollution, toxicants, nutrients

Sediment Pollution

Sediment carried into ocean by runoff, making waters turbid which reduces photosynthesis

Toxicants

• Chemicals in sunscreen

• Oil from roadways

• Pesticides from runoff

Nutrients

• Ammonia from animal waste

• Nitrates/phosphates from runoff

Petroleum Effects on Earth's Oceans

Economy = Recreation, Tourism, Fishing

• Difficult to remove

• Highly toxic to marine animals and microorganisms (algae)

How does oil spread on the water?

Travels hundreds of miles below and across surface

• Leaves behind a thick covering on shorelines

Oil Spill Effects on Animals

• Covers birds’ feathers or mammal fur = can’t fly

  • Reduces animals layer of insulation

• Toxicity

  • Consume oil when hunting other animals

  • Whales/Dolphins inhale oil

• Sunken oil smothers and kills bottom-dwelling organisms

Sources of Oil Pollution

• Spills—Oil Tanks, Pipelines: Hydrocarbons in crude oil = toxic

  • EXXON Valdez: 1989 Oil banned in Alaskan coast b/c bumped into iceberg and killed marine animals

  • Drilling: Often experience leaks

  • →

Effects of Oil Spills

• Decrease Fish

  • Decrease Revenue: Tourism, restaurants

• Settle in root structures of estuaries (mangroves/marshes)

  • Remove Habitats: fish/shellfish breeding grounds

Oil Spill Process

• Underwater oil well explodes

  • ex. BP Gulf Spill

• Tanker Runs into rock/iceberg → Punctured

  • ex. EXXON Valdez

Common Cleaning Approach to Oil

Containment → Vacuum

• Containers: Extending oil containment booms with plastic barriers floating on water for several meters

• Boats: Giant vacuums suck up oil

Misc. Approaches to Cleaning Oil Spills

• Chemicals: that break up & disperse oil before it hits shoreline

• Burning: Air pollution + Leaves thick byproduct

• Genetic Engineered Bacteria