Cycles of Matter

Chapter 3 The BiosphereSection 3-3; pages 74-80

BIOGEOCHEMICAL CYCLES-connecting the biological, geological, and chemical aspects

of the biosphere

Matter within ecosystems is recycled within

and between ecosystems

Matter Statement:

BIOGEOCHEMICAL CYCLES

Cycle - water, carbon, oxygen, nitrogen & other elements cycle from the abiotic (“geo” nonliving environment) to biotic (“bio” living organisms) & then back to the environment.

Simply put, biogeochemical cycles pass the same molecules around again and again within the biosphere.

bioticabiotic

BIOGEOCHEMICAL CYCLES

Most element cycles have an atmospheric “bank” where the element is found in large amounts.

atmosphere

“bank”

BIOGEOCHEMICAL CYCLES

Decomposers (or combustion or erosion) break down organic matter.

What is the result of their actions?

RIP

atmosphere“bank”

Organisms release elements in daily activities or after death.

Elements move from the

“bank” into organisms.

BIOGEOCHEMICAL CYCLES

Three example cycles:

– Water

– Carbon (carbon-oxygen)

– Nitrogen

H2O C

N O

WATER CYCLE evaporation – heating of water from

liquid to atmospheric gas. condensation – cooling of water from

vapor to tiny droplets that form clouds. precipitation – droplets too large to be

contained in clouds and water returns to earth as rain, snow, or hail.

transpiration – evaporation of water from leaves of plants.

runoff – excess water from precipitation that comes from streams and rivers and carried to oceans and lakes.

accumulation – collection of water on earth.

http://ga.water.usgs.gov/edu/watercyclesummary.html

Accumulation

Refer to Figure 3-11, page 75

CARBON CYCLEThe exchange of gases during

photosynthesis and respiration is a major example of the living-nonliving cycle of carbon-oxygen.

respirationphotosynthesis

O2

CO2

CARBON CYCLE

How does carbon enter the living part of the cycle?

CO2 + H2O ----> C6H12O6 + O2

CO2CO2

CO2

CO2 CO2

CO2

CO2CO2

CARBON CYCLE

Carbon is returned to the atmosphere environment by:

– cellular respiration

– erosion

– combustion

– decomposition

CARBON CYCLE respiration – process where organisms

obtain energy from breakdown of glucose.

photosynthesis – plants use light energy (sun) to make glucose.

decomposition – breakdown of dead organic matter.

combustion – burning of fossil fuels (gas, petroleum, coal) which release CO2 into atmosphere.

erosion – runoff of soil into body of water

Carbon Cycle

Refer to Figure 3-13, page 77

http://www.windows.ucar.edu/earth/climate/images/carboncycle.jpg

NITROGEN CYCLE

79% of the atmosphere is nitrogen gas but it is in a form most living things cannot use.

N2free

nitrogen

NITROGEN CYCLE

If we can’t take in free nitrogen, how do we acquire it so we can use it in our bodies?

Why do we need nitrogen in our bodies?

NITROGEN CYCLEHow do we acquire usable

nitrogen?Nitrogen-fixing bacteria convert

nitrogen into nitrates.Plants absorb nitrates.Animals eat plants.

N2

in airnitrogen-fixing

bacteria

NITRATES

NITROGEN CYCLEHow does the nitrogen return to

the atmosphere?Denitrifying bacteria convert

the nitrates back into nitrogen.

N2

in airnitrogen-fixing

bacteria

NITRATES

denitrifyingbacteria

NITROGEN CYCLE

Why do we need nitrogen?

Nitrogen

protein

?

NITROGEN CYCLESimplified

Free N2 in Atmosphere

nitrogen-fixingbacteria

NITRATES

denitrifyingbacteria

RIP

Organicmaterial

NITROGEN CYCLESimplified

free N2 bank – atmosphere nitrogen fixation – conversion of atmospheric

nitrogen to ammonia nitrates – converted form of nitrogen from

atmosphere. organisms – living things organic material – components of living things

made of C, H, O, N denitrification – ammonia and nitrates converted

to nitrogen and released back into atmosphere

N2 in Atmosphere

NH3

NO3- & NO2-

Refer to Figure 3-14, page 78

All Cycles Are Related