2.3 Flows of Matter -Nutrient CyclesMrs. PageESS2015-2016

Significant Ideas

• Ecosystems are linked together by energy and matter flows.

• The Sun’s energy drives these flows. Humans are impacting the flows of energy and mater both locally and globally

Transfers vs Transformations

• Transfers – flows through a system, often involve changes in location–Biomass moves from producers through food chain

–Water moves from a river to the ocean

–Energy moves from the sun to a plant leaf

• Transformations – interactions within a system and formation of new products or changes of state–Light energy is converted to chemical energy

–Glucose is broken down into water and carbon dioxide

Producers

• Convert light energy into chemical energy

• Provide food for the base of the food chain/web

• Release oxygen into the atmosphere

Consumers

• Pass energy from one organism to another

• Release nutrients back into the soil

Explain the role of producers, consumers and decomposers in the ecosystem.

Decomposers

• Release nutrients back into the soil

• Energy flows through ecosystems as organisms capture and

store energy, then transfer it to organisms that eat them.

• These organisms are grouped into trophic levels...

Microorganismsand other

detritivores

Tertiary consumers

Secondaryconsumers

Primary consumers

Primary producers

Detritus

Heat

SunChemical cycling

Key

Energy flow

Trophic Levels:

Route of energy flow

- food chain

- food web

- pyramid of numbers

Primaryproducers

100 J

1,000,000 J of sunlight

10 J

1,000 J

10,000 J

Primaryconsumers

Secondaryconsumers

Tertiaryconsumers

Cellular

respiration100 J

Growth (new biomass)

Feces

200 J

33 J

67 J

Plant material

eaten by caterpillar

Where does the energy go?

Four things are needed for photosynthesis:

Travels up from the roots

WATER

Enters the leaf through small holes on the underneath

SUNLIGHT Specific wavelengths of light gives the plant energy

CHLOROPHYLL

The green stuff where the chemical reactions happen

CARBON DIOXIDE

ENERGY TRANSFORMATIONS

PHOTOSYNTHESIS

CELLULAR RESPIRATION• Transformation of chemical energy in food into

chemical energy cells can use: ATP

• These reactions proceed the same way in plants and

animals. Process is called cellular respiration

• Occurs in the mitochondria of plant or animal cells

• Overall Reaction:

• C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

Biogeochemical CyclesNutrients exist in stores of chemical elements

FOUR main reservoirs where these nutrients exist are:

1) Atmosphere – carbon (C) in carbon dioxide (CO2), nitrogen (N) in atmospheric nitrogen (N2)

2) Lithosphere - the rocks – phosphates (PO4), calcium in calcium carbonate, potassium in feldspar

3) Hydrosphere - the water (H2O) of oceans, lakes, streams and aquifers

4) Soil - nitrogen (N) in dissolved nitrate, (NO3) carbon (C) in carbonic acid (H2CO3)

Living Organisms and Nutrient Cycles

Living organisms are a reservoir (stores) in which carbon exists in carbohydrates (mainly cellulose) and fats, nitrogen in protein, and phosphorus in ATP

• In studying cycling of water, carbon, nitrogen, and other chemicals, ecologists focus on four factors:

–Biological importance of each chemical

–Major reservoirs (stores) for each chemical

–Forms in which each chemical is available or used by organisms

–Key processes driving movement of each chemical through its cycle

Factors that Affect the Store and Transfers of Nutrients

• Amount and type of weathering

• Run-off and soil erosion

• Amount of rainfall

• Rate of Decomposition

• Type of Vegetation

• Age & health of plants

• Density of Plants

• Water (H2O) is essential to all

organisms

• 97% of the biosphere’s water is

stored in the oceans, 2% is in

glaciers and polar ice caps, and

1% is in lakes, rivers, and

groundwater

• Water moves by the processes of

evaporation, transpiration,

condensation, precipitation, and

movement through surface and

groundwater (transfers)

The Water Cycle

• Carbon-based organic molecules are essential to all organisms

• Carbon stores include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, and the atmosphere

• CO2 is taken up via photosynthesis and released via respiration

• Volcanoes and the burning of fossil fuels contribute CO2 to the atmosphere

The Carbon Cycle

Carbon CycleUse the following information to make a systems diagram of the carbon cycle:

1. Storages – atmosphere (CO2), fossil fuels (oil, coal), organic storages (producers, consumers, decomposers), soil, oceans

2. Transfers– Herbivores eating producers

– Carnivores eating herbivores

– Decomposers absorbing nutrients from dead organic matter

– Carbon dioxide from the atmosphere dissolving into rainwater & the oceans

3. Transformations–– Photosynthesis (energy conversion & CO2 glucose)

– Respiration (Glucose CO2)

– Fossilization (dead organisms fossil fuels by incomplete decay and pressure)

– Limestone (calcium carbonate) formed from shells and corals being crushed into sedimentary rock

– Burning fossil fuels releases CO2 and CO into the atmosphere

Carbon Cycle

Humans and the Carbon Cycle

• Current global emissions from burning fossil fuels is about 5.5 GtC(1 gigaton = 109 tons)

– 20% natural gas

– 40% coal

– 40% oil

• Deforestation adds another 1.6 GtC per year

• How do you think this affects the global system?

Use the following information to make a systems diagram of the nitrogen cycle:

1. Storages – organisms (amino acids), soil, fossil fuels, atmosphere (N2), water bodies

2. Transfers

– Herbivores consume producers and carnivores consume herbivores

– Decomposers absorbing nutrients from dead organic matter and excrement

– Plants absorbing nitrates (NO3-) through roots

3. Transformations–

– Lightening transforms N2 in atmosphere into NO3 (nitrogen fixation)

– Nitrogen-fixing bacteria transforms N2(g) into ammonium ions (NH4+)

– Nitrifying bacteria transform ammonium (NH4+) ions into nitrite (NO2

-) and then nitrate (NO3

-) (nitrification)

– Denitrifying bacteria transform nitrates (NO3-) into nitrogen N2 (denitrification)

– Decomposers break down organic nitrogen (proteins) into ammonia (deamination)

– Nitrogen from nitrates is used by plants to make amino acids and proteins (assimilation)

• Nitrogen is a component of amino acids,

proteins, and nucleic acids

• The main store of nitrogen is the

atmosphere (N2) 80%

• N2 is converted to NH3 via nitrogen-

fixing bacteria

• N2 is converted to NO3− via lightening

• Organic nitrogen is decomposed to

(ammonium) NH4+ by ammonification,

and NH4+ is decomposed to (nitrate)

NO3– by nitrifying bacteria; NH4

+ and

NO3– are assimilated by plants

• Denitrifying bacteria convert NO3– back

to N2

The Nitrogen Cycle

NOTE: N2, NO, N20, and NO2 are not usable by plants (all but N2 contribute to smog.)

NO3- (nitrate) and NH4

+ (ammonium) forms of nitrogen are biologically usable

Nitrogen Cycle: Key Points

• Nitrogen is in the atmosphere as N2 (80%)

• 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 plants and cyanobacteria

– Industrial process – Haber process used to make fertilizers (energy intensive)

• Nitrogen limits plant growth

• Nitrogen is easily lost from biological systems

Humans and the Nitrogen Cycle

• Humans impact the natural cycle by:

– Removing plants and animals for food

– Using artificial fertilizers (made by Haber process) which adds nitrogen to the ecosystem

– Planting legumes (root nodules have nitrogen-fixing bacteria) enriching soil

– Runoff can leach nitrogen from soil

– Runoff can carrying artificial fertilizers into lakes leading to eutrophication

List Some Examples of Transformations

Examples of Transformations

1. 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)

HOMEWORK•Read pp. 85-96

•To Do pp. 97 & 98