Biogeochemical cyclesHow matter cycles through systems

What are the components of a system?

• Inputs and outputs

• One way flow of energy

• Cycling of matter

Water, why is it important?

• Makes up >50% of mammal body weight • Allows molecule move in and between cells• Allows for plants to move nutrients• Dissolves and removes toxic materials

Hydrologic cycle• Aka water cycle, cycles water through the hydrosphere

Where is the water?

71% of Earth is covered in water but thereisn’t enough fresh water to go around

Water cycle

Water cycle1.Evapotranspiration- Evaporation and transpiration that takes place on land. Due to solar energy

2.Condensation- Water in atmosphere cools and condenses around condensation nuclei

3.Precipitation- Downward movement of water from the sky

4.Infiltration and percolation- Conversion of surface water into ground water.

I= Movement of water into the soil. - P=Downward movement of water THROUGH

water.5.Runoff- Due to gravity and nonpermeable material

6. Collection- Pooling of surface water

Looking closer at human impact• Ground water contamination• Pollutants get into water and are leached downward

through soil to aquifers.

• Removal of vegetation and plant biomass• Flooding and soil erosion• Decrease evapotranspiration• Increase surface runoff• Decrease infiltration

• Water depletion• withdrawal > replenishment

Human impact continued…

• Draining and filling in of wetlands• Decrease purification of water and increases runoff

• Changing permeability of soil • Increases runoff and pollutants• Decreases amount of groundwater • Limits purification of water

• Change in water quality• Nitrogen and phosphates getting into water supple

(will get to this later)

Question…• What are 3 ways in which your lifestyle directly or indirectly

affects the hydrologic cycle?

Carbon: why is it important• Backbone of all organisms and most important element in

living things• 20% of total biomass

• Base of organic compounds• Carbohydrates• Lipids• Proteins• Nucleic acids

Cycling of carbon can be broken down into:

FAST• Associated with biotic

components of cycle• Photosynthesis• Respiration• Exchange

SLOW• Associated with the

abiotic components of cycle• Sedimentation and burial• Extraction • Combustion

Without human activity the carbon cycle is at balance. • Fast components of removal and input even each

other out.• Slow components of removal due to fossilization

equal the slow process of weathering of carbon containing rocks

Question• What are 3 ways in which your lifestyle directly or indirectly

affects the carbon cycle?

Human impact on carbon cycle• We have altered the balance of input and output

of carbon in the atmosphere• Removal of fossilized carbon and combustion of

fossil fuels increase amount of CO2 in atmosphere• Increasing temperatures of atmosphere

increases the amount of carbon absorbed by oceans creating carbonic acid (H2CO3) and lowering the pH of ocean water. This prevents the formation of calcium carbonate (CaCO3)

• Removal of carbon from biomass adds more Cos into atmosphere

Nitrogen cycle

• Nitrogen is a limiting factor for producers• Biotic or abiotic component that controls /

prevents growth• Without nitrogen plants cannot survive

• 78% of atmosphere is N2 but most living organisms cannot utilize this form of nitrogen• Vital in the creation of amino acids, proteins,

nucleic acids

Basic steps of the Nitrogen cycle

Human impact on the Nitrogen cycle

• Burning fossil fuels releases NO into the atmosphere which increases NO2 in atmosphere (GHG) and can ultimately lead to creation of HNO3 when mixed with water

• Production of synthetic fertilizers increases the amount of nitrate

• Removal of vegetation can deplete nitrogen from soil due to removal of nitrogen fixing bacteria.

• Too much fertilizer that isn’t assimilated by plants gets into water supply. This leads to increased primary production which ultimately results in fish kills due to hypoxic conditions.

Question• What are two ways in which the carbon and the nitrogen cycle

are linked

The Phosphorus Cycle

• Why do we need it?• ATP• Major component in Nucleic Acids• Phospholipid bilayers

• Limiting Nutrient• Falls below nitrogen in limiting ability but is none the

less an important factor.

The phosphorus cycle• IMPORTANT: THERE IS NO GASEOUS COMPONENT OF

PHSOPHORUS. THEREFORE IT IS A VERY SLOW PROCESS AND MAINLY DEPENDENT ON WEATHERING OF ROCKS

• Since it has a slight negative charge it has the ability to bind positively charged soil particles.

• Phosphorus also does not dissolve very easily in water, but instead settles into the sediment and is therefore a limiting factor for aquatic locations.

• Fertilizer use can add additional phosphorus into aquatic systems when moved with runoff

• This leads to increased algae growth and ultimately leads to hypoxic conditions

• Phosphates in detergents led to dead zones• Manufacturers no longer use this in detergents as of 1994 for

laundry and 2010 dishwashing• Mining of rocks remove phosphates • Deforestation leads to more phosphorus in water supplies

Human Impact on P Cycle