Chapter 4-3: Cycling of Matter

What is the water cycle? Why are plants and animals important for

carbon and oxygen in an ecosystem? Why must nitrogen cycle through an

ecosystem? Why must phosphorus cycle through an

ecosystem?

Carbon Cycle

• Carbon is an essential component of proteins, carbohydrates and fats

• C is cycled between the atmosphere, land, water and organisms – continuously

• Finite amount of carbon – must be reused

• Producers obtain CO2 and turn it into organic compounds using photosynthesis

Fuel

• Producers (plants) and consumers use carbohydrates as fuel and release CO2

• Carbohydrates are used for– 1. provide fuel (energy), – 2. biomass (growth,cells,materials) and – 3. waste (chemical and heat).

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Short term Carbon cycle

• Short term cycle

1. CO2 in air/water 2. into plants; 3. photosynthesis- 4. Makes carbohydrates 5. consumed 6. respiration (back to CO2 )

7. and biomass 8. food web

Long term Carbon cycle

• Long term cycle carbonates are added

to the soil and lakes

and fossil fuels can be created with pressure over geologic time

Other impacts

• Natural burning (forest fires) release CO2 into atmosphere

• Power plant, factory and vehicle emissions also release CO2 into atmosphere.

• Cars = 1/3 of CO2 emissions (overall total 6 billion metric tons)

Fossil Fuels

• Fossil fuels are made from fossilized trees and animals and shells…

• Hard to make/ remake when used up – because

• Not a short term situation…. Don’t let the pictures fool you into thinking that road-kill becomes carbon in the soil….and its instantly a fossil

CLIMATE CHANGE vs. GLOBAL WARMING

• Climate change means the there is an overall, long term change in the climate….more storms, more draught, higher temps as well as colder temps….more extremes in conditions

• Global warming would apply to areas that are getting warmer.

• There is a lot more going on.– Some changes due to

activities of man (pollution, industry, deforestation….)

– Some changes may be part of natural cycle

NITROGEN CYCLE

• All organisms need nitrogen to build amino acids so they can make proteins.

• Cells are composed of proteins – “Everything in the cell either is protein or is run by a protein”

• N is also found in the nucleic acids (ATCG and U) that make up DNA

Atmospheric Nitrogen

• 78% of atmospheric gases are nitrogen

• Atmospheric nitrogen (N2 gas) is not usable by most organisms

• Organisms that can “fix” N2 into usable formats are called Nitrogen fixing bacteria.

Nitrogen Fixation

• Nitrogen fixing bacteria are crucial to the nitrogen cycle.

• Bacteria take N2 gas from the atmosphere and turn it into usable molecules

• Nitrogen fixing bacteria have symbiotic relationships with cells in the roots of legumes (beans, peas & clover --soybeans & hay)

• N2 is turned into nitrates and nitrites (NO2 and NO3)

• Nitrates and nitrites are released into the soil

Plants and nitrogen

• Plants that are not legumes get NO2 and NO3 from soil and use it to build proteins

• Decomposers break down waste, urine, dead leaves, decaying organisms…. Into nitrogen sources. (ammonia, NH3, NH4

+ and some gaseous N2)

• Lightening strikes can also convert N to usable forms

Assimilation, Ammonification, etc.• The process by which organisms get nitrogen

– Plants assimilate nitrogen from the soil into the organic compounds they produce

– Animals (heterotrophs) assimilate nitrogen that is in the amino acids and nucleic acids they eat from producers into their own body mass.

• Ammonification is the process where nitrogen containing compounds are broken down and released from waste or decay (turned to NH4)

• Nitrification – converts ammonia to NO3 and NO2

• Denitrification – takes NO3 and NO2 and turns it back into nitrogen gas in the atmosphere

Water Cycle

• Water has to move to and from the atmosphere, land and bodies of water.

• Water is also found under the surface as ground water.

• Water in lakes, streams, rivers, oceans, wetlands and puddles is called surface water

• ¾ of the surface of the globe is covered in water• Only % of it is fresh water (the rest of it is

marine=salty)….most of North America’s fresh water is in the Great lakes region

Flow of Water

• Solid, liquid and gas (vapor) forms

• Land, ice, bodies of water, the atmosphere and LIVING ORGANSIMS

• Physical factors like temperature, temperature differences, wind and pressure impact water flow.

Water cycle terms

• Precipitation any form of water that falls from the clouds to the earth (rain, snow, sleet and hail)

• Transpiration the process by which plants release water vapor to the air from their stomata

• Evaporation water changing state from liquid to vapor (gas)

• Water vapor water in a gas form

More vocabulary

• Run-off water that falls on a solid surface and then is absorbed into the soil or moves toward a river/ body of water

• Percolation the process of water being absorbed into the soil/becoming ground water

• Ground water

Water Cycle

• Water in the atmosphere (clouds)• Change in temp and/or pressure• Precipitates• Falls on

– Land and percolates into soil (not just in soil but also springs and water table)

– Land and is run-off; goes toward body of water– Water and stays

• Water evaporates from surface of lake/ocean • Water back in atmosphere

• Water is used by plants

• Required for photosynthesis

• 6CO2 + 6H2O C6H12O6 + 6O2

• Water is a large component of all living things – cytoplasm, blood, tissue, roots, stems

• Water is needed for chemical reactions like dehydration synthesis and hydrolysis