What organism is important in cycling of nutrients?

Agenda for Friday Jan 9th 1.Quiz2.Cycles Notes

Cycles in Earth• Law of Conservation of Mass

• Biogeochemical cycles – exchange of matter through biosphere

• Reservoirs/sinks – places where matter & nutrients stored

Why is it important that nutrients cycle?

Water never leaves the Earth. It is constantly being cycled through the atmosphere, ocean, and land. This process, known as the water cycle, is driven by energy from the sun.

Water Cycle

Water Cycle1. Evaporation – liquid water becomes a gas

– Transpiration – evaporating off plants

2. Condensation – water changing from gas to liquid

3. Precipitation – water falling to Earth from atmosphere

4. Run-off – water running over the land– collect in the oceans, lakes or rivers

5. Infiltration – water seeping into the ground– Ground Water- stored in underground caverns and

porous rock– Provides water for the soil, streams, rivers, and oceans

Human impacts on water cycle• Removing forests and vegetation increases runoff and

erosion, reduces transpiration and lowers water tables• Agriculture

– depletes rivers, lakes and streams – increases evaporation

• Damming rivers increases evaporation and infiltration • Emitting pollutants changes the nature of precipitation• The most threatening impact: overdrawing groundwater

for drinking, irrigation, and industrial use

What is transpiration?

Agenda for Monday Jan 12th 1. Cycles webqwest

Where is carbon stored in the environment?

Agenda for Tuesday Jan 13th 1.Start climate change paper

Test Next Wednesday

Where is most of the water on earth?

Agenda for Thursday Jan 15th 1.Finish Cycles2.Go over HW3.Species relationship notes

Carbon and Oxygen Cycles• The movement of carbon from the environment into living things and back again• Carbon is essential because it is part of our molecules

Where is the carbon?• Stored in oceans, trees, air

– Many animals pull carbon from water to use in shells, etc.– Oceans contain earth’s largest store of carbon

• Fossil fuels– Oil, coal, natural gas

• Respiration and life processes– Methane – cows

Ways carbon moves

• Photosynthesis- carbon moves from the environment into living things

• Respiration- carbon moves from living things back to the environment

• Decomposition- carbon moving from dead organisms back to the environment

• Combustion- Burning fossil fuels releases carbon back into the atmosphere

Carbon is released into the atmosphere in several ways

• Respiration by plants and animals.

• Decay of animal and plant matter.

• Combustion of organic material

• The ocean releases CO2 into the atmosphere. • Volcanic eruptions and metamorphism

Carbon in the Atmosphere• Greenhouse effect

– Trapping of heat by molecules (water, CO2)

• Excessive carbon in the atmosphere raises temp.

Human Impact

• Fossil fuels – Releases stores of carbon – Burning anything releases more carbon into

atmosphere

• Deforestation and Habitat Destruction– Fewer plants mean less CO2 removed from

atmosphere

Humans affect the carbon cycle

• Today’s atmospheric carbon dioxide reservoir is the largest in the past 800,000 years– It is the driving force behind climate change

Human-Produced Greenhouse Gas Levels

Effects of Climate Change

Sea Level Rise

• Melting of– Greenland Ice Sheet

– Antarctic Ice Sheet

– Glaciers and ice caps

• Expansion of heated (warm) sea water

2 – 4 C warming by ~2100

0.18 - 0.59 meter rise in sea levelIPCC (2007)

Other Effects

• Ecosystem change– Loss of species

• Flooding of coastal communities• Spread of diseases• Increase of extreme weather events

Nitrogen Cycle• Nitrogen is used by plants and animals

– Proteins, nucleic acids

• Nitrogen is found in atmosphere and is unusable– Converted to a useable form through nitrogen fixation

• Special organisms/bacteria that convert – legumes

• Lightning

– Animals get nitrogen from eating plants

• Returned to soil when animals urinates/dies– Denitrification – nitrogen is converted back to gas

Humans affect the nitrogen cycle• Haber-Bosch process = production of fertilizers by

combining nitrogen and hydrogen to synthesize ammonia

• animal waste • Excess Nitrogen can cause Eutrophication • causes aquatic life to die due to low levels of

oxygen• High levels of ammonia is toxic to animals

Decreasing Nitrogen Pollution

• Scientists, farmers and policymakers are encouraged to – Decrease fertilizer use– While safeguarding agriculture

• Using new farming methods• Planting cover crops• Maintaining wetlands

Humans affect Cycles• shifting carbon from fossil fuel reservoirs into the atmosphere

• shifting nitrogen from the atmosphere to the planet’s surface

• depleting groundwater supplies