Where are we so far

• Environment defined & explored• Climate and Climate Change Presented• Ideas regarding environmentalism,

sustainability, happiness– There is a crisis and we can approach it from

different directions• Everyone in Priuses• Example from Port Alberni, BC• Moving towards sustainability and happiness

• Places for renewal• Biogeochemical Cycles

Two Options

• Mt Teneriffe

• I-90 to North Bend, Mt. Si Road, cont. to school bus turn-around

• Cutthroat Pass

• I-5 to Mt. Vernon, Highway 20 to Rainy Pass

Biogeochemical Cycles - Lecture 1

Class Lecture Goals

1. What are systems?

2. What are biogeochemical cycles?

3. Why are they important?

4. What is common about them?

5. Carbon and nitrogen cycles

6. Water Cycle (Monday)

What is a system?

• System: a collection of matter, parts, or components which are included inside a specified, often arbitrary, boundary. Example: Ecosystem

• Systems often have inputs and outputs.• For dynamic systems, by definition, one or more

aspects of the system change with time.– Example of a simple dynamic system: bathtub or your

‘bank’ account.

• The boundary of a dynamic system is chosen for convenience -- often the boundary is arbitraryFlux

Electric Energy

ColdWater

HotWater

FluxFlux

PoolHeatLoss

Output

Input

Carbon dioxide

C-pool

SugarSugar

Night

Where are we?

1. What are systems?

2. What are biogeochemical cycles?

3. Why are they important?

4. What is common about them?

5. Carbon and nitrogen cycles

6. Focus on the Water Cycle (Monday)

What are biogeochemical cycles?• Earth system has four parts

– Atmosphere– Hydrosphere– Lithosphere– Biosphere

• Biogeochemical cycles: The chemical interactions (cycles) that exist between the atmosphere, hydrosphere, lithosphere, and biosphere.

• Abiotic (physio-chemical) and biotic processes drive these cycles

• Focus on carbon and water cycles (but could include all necessary elements for life). N - cycle weakly touched on!

What is common amongst them?• Each compound (water, carbon, nitrogen)

typically exists in all four parts of the Earth System

• Biologically useful forms are usually in low concentrations or quantities

• There are – ‘Pools’– Fluxes in and out of pools– Chemical or biochemical transformations

• Transformations – are important– can lead to positive & negative consequences

Transformations

Examples of Transformations1. Carbon cycle: Organic compounds to CO2

(processes: respiration, decomposition, or fire)2. Carbon cycle: CO2 to organic compounds (process:

photosynthesis)3. Nitrogen cycle: N2 to NO3 (atmospheric nitrogen to

plant utilizable nitrate) (process: N-fixation)4. Nitrogen cycle: N2 to NH3 (plant utilizable ammonia)

(process: Haber-Bosch Industrial N-fixation) 5. Water cycle: Liquid water to water vapor (process:

evaporation and evapo-transpiration)6. Water cycle: Water vapor to liquid water (process:

condensation)

Policy Issue: Trees capture carbon, Carbon is stored in treesCarbon can be released slowly (respiration, decomposition)OrRapidly (fire)

Policy Issue: Rapidly growing plants (trees or crops) need nitrogen fertilizerFertilizer can come from organic and non-organic sourcesOrganic sources are inefficientInorganic sources are fossil fuel intensive

Where are we?

1. What are systems?

2. What are biogeochemical cycles?

3. Why are they important?

4. What is common about them?

5. Carbon and nitrogen cycle

6. Focus on the Water Cycle (Monday)

5000

http://www.epa.gov/climatechange/kids/carbon_cycle_version2.html

Carbon Cycle

Carbon Cycle Data

• Burning of fossil fuels

• Land conversion

• Cement

• Role of Oceans

• Role of terrestrial plants (trees & soils)

760

59

Lithosphere

Increase biological C fixation

• Focus on oceans

• Proposal to add iron

• Where did idea come from?

• Would it work?

Buesseler & others suggest the following about ocean Fe fertilization

1 2 3 4

6%

61%

28%

6%

1. Unclear how long effect lasts

2. Do not understand all the potential biogeochemical impacts

3. Impact potentially small

4. Effects on other greenhouse gases is non-existent or small

Pick the false statement

Changes in Atmospheric C02

QuickTime™ and a decompressor

are needed to see this picture.

Key Aspects of the Carbon Cycle• Carbon is the skeleton of all life.• Foundation of the food chain or web• Foundation of fossil fuels• Foundation of ‘carbon-neutral’ based fuels

– Ethanol– Cellulosic biofuels– Biodiesel

• Carbon dioxide is a critical gas:– Taken up by plants in photosynthesis– Released by plants and animals in respiration– Released during decomposition (and fires)– Greenhouse gas

Question: Photosynthesis is an example of a pool

1 2

65%

35%

1. True

2. False

Where are we?

1. What are systems?

2. What are biogeochemical cycles?

3. Why are they important?

4. What is common about them?

5. Carbon and nitrogen cycle

6. Focus on the Water Cycle (Monday)

Nitrogen Cycle

http://soil.gsfc.nasa.gov/NFTG/nitrocyc.htm

Forms of Nitrogen (N2)• N2 - inert gas, 78% of the atmosphere• NO, N20, NO2 - other gases of nitrogen, not directly

biologically important. Part of the gases found in smog.

• NO3- (nitrate) and NH4

+ (ammonium) -- ionic forms of nitrogen that are biologically usable.

Biological Forms:

Plants: Nitrate (NO3-) and ammonium (NH4

+)

Plants to animals (amino acids, proteins)

Animal to animal (amino acids, proteins)

Biological Nitrogen Sources over Time

Nitrogen Cycle: Key Points

• Nitrogen is in the atmosphere as N2 (78%)

• N2 is an inert gas and cannot be used by plants or animals

• N2 can be converted to a usable form via– Lightening – N-fixing micro-organisms (free living, assoc. with plant)– Industrial process (energy intensive)

• Plant growth is often limited by low soil nitrogen• Nitrogen is easily converted & lost from biological

systems (e.g., fire)

Knowing something about the carbon and nitrogen cycle we will

explore corn ethanol as a source of energy

• Constraints:– Not a discussion of energy independence

or balance of trade

• An assessment of how corn is involved in the C and N cycles.

• How we must follow the first and second laws of thermodynamics

Burning dried plants or compounds from dried plants is similar to recycling

1 2

64%

36%

1. Yes

2. No

Theoretically, burning ethanol from corn vs. burning oil should reduce the rate we are

adding carbon dioxide to the atmosphere.

1 2

29%

71%1. True

2. False

What are the two laws of thermodynamics?

• Conservation of Energy: Energy can be transformed from one form to another form; energy cannot be created nor destroyed.– Example: Light energy from the sun is converted to

chemical energy represented by the energy in chemical bonds (carbon-carbon units in sugar).

• Entropy: Each transformation results in heat production and therefore the form of energy becomes increasingly less able to do work.– Example: Inefficiency of

• Photosynthesis• Food chain

Steps in Ethanol Production• Sun -- Sugar -- corn plant• Corn plant -- sugar -- ethanol

• Carbon dioxide produced in– Farming

• Planting• Fertilizing and fertilizer production (N)• Irrigation• Harvesting

– Transportation– Processing– Distribution

Purely from a Carbon and Nitrogen cycling consideration, ethanol

production …

1 2 3 4 5

1. Is clearly an outstanding strategy

2. Is a strategy worth considering

3. Is a strategy worth considering, but with proper cautions

4. Is a totally bad idea

5. I walk & bike and its not my problem

Summary

• 1. What are systems?

• 2. What are biogeochemical cycles?

• 3. Why are they important?

• 4. What is common about them?

• 5. Carbon and nitrogen cycles

• Monday: water cycle