Cycles Human Impacts The Hydrologic Cycle The Carbon

Cycles & Human Impacts

The Hydrologic Cycle

The Carbon Cycle

The Nitrogen Cycle

The Phosphorus Cycle

Understanding cycles provides a basis for determining how disturbances change ecosystems. In what ways are human interactions disturbing the hydrologic, carbon, nitrogen, phosphorus, and sulfur cycles?

Hydrologic • Removal of large quanities for use in irrigation • Removal of vegetation causes increased run off and less infiltration • Excess nutrients (fertilizer/sewage) cause algal blooms, hypoxic conditions, & dead zones. Eutrophication! Carbon • Fossil fuel combustion- releases C from rocks; adds CO 2 to atm & increased acidity of oceans • Animal waste- adds CH 4 to atm • Deforestation – less CO 2 removed from atm

Nitrogen • Combustion NOx + H 20 HNO 3 in atmosphere • Fertilizers- increases N into aquatic ecosystems and causes plant/nutrient pollution (eutrophication) Phosphorus • Fertilizers, detergents- plant/nutrient pollution (eutrophication) Sulfur • • Coal combustion Smelting sulfide minerals Both of which result in Sox exhaust + H 20 H 2 SO 4 AMD

The N & P Cycles and Impacts on Aquatic Ecosystems Define nutrient. How do excess nutrients like nitrogen (and/or phosphorus) affect population sizes? How might a decrease in nutrients affect population sizes?

Eutrophication An aquatic ecosystem’s response to an influx of nutrients (N & P mostly). Leads to slow death of pond or lake

Eutrophication 1. Nutrients enter water 2. Algae “blooms”; limits Ps and decreases O 2 production 3. Algae die; Dead algae fall to bottom, begin decomposing 4. Decomposers consume O 2 breaking down dead algae 5. Other organisms “suffocate” from lack of oxygen hypoxia

Eutrophication cwh. triplepointwater. com

Where do the excess N & P come from? Humans! Nutrients run off from lawns, farms, golf courses, etc… • Nitrogen – Fertilizers – Livestock waste • Phosphorus – Laundry detergents – Livestock waste

Eutrophication Video 1 http: //uccpbank. k 12 hsn. org/courses/APEnviron mental. Science/course%20 files/multimedia/less on 78/animations/5 a_Lake_Eutrophication. html

Eutrophication Videos 2 & 3 Montreal Lakes http: //youtu. be/1 sv. W 3 KSxjvc Barnegat Bay http: //youtu. be/N_m. Y 99 MB 3 ew