Biogeochemical Cycles• Bio means…

– life

• Geo means…

– Of earth: parts of earth are

• Land, air, water

• Chemical means…

– Molecules and/or compounds

• Cycle means…

– Repeatedly

• Cycling of materials between the environment and organisms

• Chemical and biological processes

• Examples

– Water cycle

– Nitrogen cycle

– Phosphorus cycle

– Carbon cycle

Plants obtain nitrogenfrom nitrogen-fixing

bacteria and pass it toother organisms through

the food chain

Cycles of Matter

• No definite beginning or end like food chain (remember, energy flow is unidirectional)…matter is recycled

• Does not use up matter…transforms it

• Biogeochemical process– Pass same molecule/compound/element through

biosphere over and over• Organism to organism

• First Part of biosphere (air, land, water)

• Second Part of biosphere (air, land, water)

Biogeomchemical cycles

• Carbon-oxygen

• Phosphorus

• Water

• Nitrogen

Water Cycle

Water cycle-

•Water Cycle• Evaporation: water (in oceans, rivers, lakes) turns to water vapor and

rises

• Transpiration: water evaporates through the stomata of a plant’s leaves and becomes water vapor

– Adhesion and cohesion enable water molecules to move from roots to leaves

– Stomata: tiny openings in the leaves of plants

• Condensation: water vapor cools down and condenses in atmosphere to make CLOUDS

• Precipitation: water returns to surface as rain, snow, ice

• Run-off: water that moves from mountains and hills to rivers and stream and then eventually to ocean

• Seepage: water that seeps into the soil and is either taken up by plant roots or becomes part of ground water

• Ground water: Water that exists beneath the earth's surface in underground streams and aquifers that eventually becomes part of the ocean

Water Cycle Impact

• Deforestation– Freshwater returns to atmosphere by

TRANSPIRATION from tropical forests

– Cut down tropical forest=reduce water vapor in air=changes in precipitation patterns and effects ecosystems

• Irrigation and household water use– Draws water up from aquifers and rivers

– If rate at which H2O is used is FASTER than the water cycle can replace it, rivers nad aquifers may run dry (effects ecosystems)

Carbon-oxygen cycle

• Carbon is the main component of all living things

• Carbon is found in glucose, which is the fuel for LIFE!

• What other things do we fnd carbon in?

Carbon cycle

Carbon released as

• Carbon dioxide

– Animals and humans release CO2 by cellular respiration

– Volcanic eruptions

– Burning of fossil fuels (oils)

• Methane (CH4)

– Grasses and animals release

• Bicarbonate ions

– Found in rock and released during erosion

Carbon is taken in by

• Plants

• When light is present, plants use photosynthesis to make CO2 and H2O into glucose and oxygen

Carbon Cycle

Carbon cycle impacts• Atmospheric CO2 levels have steadily risen (more

industrialized)• Burning of wood and fossil fuels release CO2 into atm• Deforestation affects carbon cycle

– Def: clearing of forests for lumber, agriculture, etc.– Eliminates plants that absorb excess CO2 from the air– “Slash and burn” removes plants and adds CO2 to air

• Greenhouse effect– When atmospheric gases trap heat close to Earth’s surface– Makes Earth “liveable”…not a bad thing as long as it is controlled

• Global warming (theory)– Theory that there is an overall rise in global temperatures b/c of

increase in greenhouse gasses (CO2)– NOT proven

Nitrogen cycle

• Where is nitrogen found in living things?

• Proteins, nucleic acids, and more!

• Do you think nitrogen is important?

Nitrogen cycle-

Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.

Organisms can not use it in that form.

Lightning and bacteria convert nitrogen into usable forms.

Nitrogen cycle

• Nitrogen gas N2

– Nitrogen-fixation by bacteria on roots of legumes to change it into…

• Ammonia NH4+

– Nitrification by bacteria in soil to change it into… nitrates and nitrites

– Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi-aquatic environments like rice paddies.

• Nitrates NO3- and Nitrites NO4-

– Denitrification by denitrifying bacteria in soil into…

• Nitrogen gas N2

Nitrogen Cycle

Atmospheric nitrogenLightning

Nitrogen fixing bacteria

AmmoniumNitrification by

bacteriaNitrites Nitrates

Denitrification by bacteria

Plants

Animals

Decomposers

Nitrogen Cycle

Nitrogen Cycle Impacts

• Humans move large amounts of nitrogen into air or water– Sewage treatments, fertilizers

• Lots of Nitrogen in water (and phosphorus) enables algae to grow rapidly on the surface…eutrophication– As algae dies, bacteria that consumes them use up so much

available oxygen in the water that there isn't enough for the other marine organisms

• Lots of Nitrogen (and sulfur) in Air– Smokestacks and car exhaust pipes– These nitrogen and sulfur containing compounds mix with water

in the air to make NITRIC ACID and SULFURIC ACID– These acids evaporate, condense and come down as ACID

PRECIAPTATION (acid rain)– Acid Rain causes damage to soils and aquatic ecosystems

-Fertilizers used in farming-cause run-off into nearby water=increase in nutrient levels=phytoplankton to grow and reproduce rapidly=algal blooms

-This bloom of algae disrupts normal ecosystem

-uses up all the oxygen in the water-none left for other marine life -causes death of many aquatic organisms that need the oxygen

-Blooms also block sunlight penetrating the surface

-photosynthetic marine plants can’t get sunlight

-Blooms also produce toxins that are harmful to higher forms of life-Cause problems along the food chain and affect any animal that feeds on them.

Do NOT copy word-for-word!!!

Phosphorus cycle

• Where do we find phosphorus?

• Part of DNA, cell membranes, ATP and ADP

• Do you think phosphorus is important?

Phosphorus cycle

Pollution and the Environment

• Pollution: addition of substances to the environment that result in a NEGATIVE effect

• Biological Magnification– Animals take in water and nutrients and sometimes

pollutants w/them

– While energy decreases as it moves up the food chain, toxins increase in potency.

– PCBs• Disposed in industrial wastes and Soluble in lipids of

animals

• Concentration of PCBs increases in organisms tissues increase as you move up trophic levels

– DDTs• Chemical used to control mosquitoes and crop pests

• Soluble in fatty tissue

• Birds had high levels of DDT in their tissue and in egg shells, which causes shells to be brittle and young birds cannot survive

dichlor-diphenyl-trichlorethyleneC14H9Cl5

Damage to Ozone• Ozone: gas in atmosphere (O3)• Ozone absorbs UV radiation from the sun (protects

organisms on earth from harmful rays)• Chlorofluorocarbons (CFCs) is a chemical released

from aerosol cans, refrigerator units and certain manufacturing processes– Chlorine from CFCs pull off an oxygen from a molecule of

O3, making chlorine monoxide, ClO, and ozone into regular O2, and the ClO binds with another ClO making chlorine peroxide (Cl2 O2)..and now there is one less molecule of O3 in the atmosphere to protect organisms from harmful UV radiation...sun also breaks the chlorine peroxide (Cl2 O2) into chlorine atoms and another O2 molecule and the cycle continues with more carbons interacting with ozone molecules

– “Holes in the Ozone”

http://www.ozonelayer.noaa.gov/science/StratO3.jpeg

Biodiversity

• Definition: # of species in an ecosystem; the variety of ecosystems; the variety of individuals in a species

• Why is biodiversity important?– Species in ecosystem are interconnected and

depend on each other

– If one species disappears, many others affected

– Humans depend on biodiversity as well (food, shelter, clothing, medicine)

Threats to Biodiversity

• Habitat destruction

• Introduced Species

• Over Exploitation of resources

Conservation Biology• Def: application of biology to counteract the threats to biodiversity

– Focus on hot spots• Small geographic areas with high conc. of species• Cover less than 1.5% of earth’s surface• Hotspots of extinction• Contain 1/3 of all plants and vertebrates

– Understand Organism’s habitats• Helps maintain org. habitat or create new habitats• Biologists can protect key habitat factors of species

– Balance demand for resources• Save species or meet economic and social needs of people• Save a forest to protect and owl but put many loggers out of work?

– Planning for a Sustainable future• Ways nations protect environment for future:• Zoned reserves-areas of land that are relatively undisturbed by humans

– Encourage long term ecosystem conservations

• Buffer zones-areas that surround “zoned” reserve; these buffers are minimally impacted by people...no major envirm. disturbances

– Ex. Costa Rica- 8 zoned reserves

• Sustainable development- developing natural resources so that the can renew themselves and be available to the future…

– Ex. Forest corridor between farmlands

Biogeochemical activity• Each member in group needs to have their own

paper

• Fold paper in 4

• Title each box (carbon cycle, water cycle, phosphorus cycle, nitrogen cycle)

• Diagram each of the cycles in a box, make sure each arrow is labeled and each animal/plant is labeled

• On the back of each square, name the different forms the matter takes, key players (bacteria, plants, animals, activities)

• Processes that change/transform the matter