Unit 4 - AP Environmental Science

What are the roles of biogeochemical cycles? What factors contribute to eutrophication? What are the ways to prevent eutrophication? How do humans alter the BGC Cycles?

Biosphere 

The combination of all ecosystems on Earth 

Biogeochemical cycles 

The movement of matter within and between ecosystems involving biological, geological, and chemical cycles

What are the six major elements?

• Hydrogen

• Oxygen

• Carbon

• Phosphorus

• Sulfur 

• Nitrogen

CHONPS 

Closed system

Ecosystems have to recycle all of its materials, which includes the entire world 

Watershed

All the land in a given landscape that drains into a specific stream, river, lake, or wetland

The Hydrologic Cycle

1) Evaporation: The sun heats up the water and it enters the atmosphere

2) Condensation: The water forms into clouds

3) Precipitation: Water returns to the lithosphere in the form of rain or snow or hail

4) Runoff: Water moving across the land into the ocean

5)Percolation/Infiltration: Water entering the ground

6) Transpiration: Plants releasing water from their leaves into the atmosphere

How to humans interfere with the water cycle and what are some solutions?

Interference

• Farming 

• Dams

• Concrete and Blacktop

• Deforestation 

• Desertification 

Solutions   

• Conservation laws

• Green spaces

• Education

• Crops matching the climate 

The Carbon Cycle

1) Photosynthesis: Producers turn carbon into sugars

2) Cellular Respiration: Sugars are converted back into CO2 

3) Sequestration: Carbon being stored in a sink/resuviour 

4) Anthropogenic Carbon Sources: How humans use carbon (like burning fossil fuels) 

5) Combustion: Carbon being released and converted back to CO2 

Cellular Respiration vs. Photosynthesis

C6H12O6 + O2 → CO2 + H2O +36 ATP 

vs

CO2 + H2O → C6H12O6 + O6

The Greenhouse Effect

a positive feedback loop that speeds up and increases the amount of carbon in the atmosphere, making the planet warm up

Chemical Recycling

The C in CO2 turning into the C in C6 for example

How to humans interfere with the carbon cycle and what are some solutions?

Interfere

• Excessive forest fires 

• Burning fossil fuels

Solutions

• Conserving old trees

• Keeping oceans healthy 

• Limits on fossil fuels

• Using renewable sources of energy 

Where are the two major carbon sinks?

• The ocean

• The forests 

The Phosphorus Cycle

1) Weathering: how phosphorous is exposed

2) Moves through the lithosphere, biosphere, and hydrosphere (not much in the atmosphere)

3)Slow moving cycle due to rocks

4) Phosphate in fertilizer can end up in plants and streams

5) Excretion and decomposition can release phosphorus in plants and animals

6) Phosphorus contributes to the building of sedimentary rock after being dissolved in the ocean

7) Geological forces push these sedimentary rocks up

What does the P stand for in ATP?

Phosphorus! 

What is uplift?

When rocks are exposed and phosphorus is able to escape

How to humans interfere with the phosphorus cycle and what are some solutions?

Interference 

• Over-fertilization

• Mining

• Burning

Solutions

• Limit excessive fertilizers 

• Use water treatments

• Preserve wetlands

The Sulfur Cycle

1) Primarily contained by amino acids

2) Sourced by volcanic eruptuons and burning fossil fuels

What are amino acids? 

Bio-molecules! 

Acid Rain

Acidic rain that changes the PH level of the soil

H2SO4

Sulfuric Acid

The Nitrogen Cycle 

1) Nitrogen Fixation: N2 from the atmosphere gets converted into NH3 and then to NO2 

2) Assimilation: Producers take up NO3 and NH4 

3) Ammonification: Decomposers break nitrogen down into NH4 (ammonium) 

4) Nitrification: Bacteria turn NH4 into NO2 (nitrite) and NO3 (nitrate) 

5) Dentification: Bacteria turn NH3 into N2O and eventually N2 and it goes back into the atmosphere