Biogeochemical CyclesSB4b. Explain the flow of matter

and energy through ecosystems

by explaining the need for cycling

of major nutrients (C, O, H, N, P).

describe the flow of essential

elements from the

environment through living

organisms and back into

the environment.

Biogeochemical Cycles

Reservoir

where nutrient is stored

Assimilation

how nutrient is used

Release

how nutrient leaves living things

Key Terms

Hydrological Cycle1. Reservoir – oceans, air

(as water vapor), groundwater, lakes and glaciers;

2. Assimilation – plants absorb water from the ground, animals drink water or eat other organisms which are composed mostly of water.

3. Release – plants transpire, animals breathe and expel liquid wastes.

Phases of Hydrological Cycle

• Evaporation – process by which water changes

from a liquid into an atmospheric gas

• Transpiration – loss of water from a plant

through its leaves

• Condensation – process by which water

changes from an atmospheric gas into a liquid

• Precipitation - rain, sleet, hail, snow and other

forms of water falling from the sky

Hydrological Cycle

Carbon Cycle(carbon is required for building organic compounds)

1. Reservoir – main: ocean, atmosphere (as CO2), fossil fuels (oil, coal natural gas),

2. Assimilation – plants use CO2 in photosynthesis; animals consume plants.

3. Release – plants and animals release CO2through respiration and decomposition; CO2 is released as wood and fossil fuels are burned.

Carbon-Oxygen Cycle

• Photosynthesis and respiration cycle

Carbon and Oxygen atoms through an

ecosystem

• Consumers die → decomposers give off

CO2

• Consumers die → heat, pressure, time →

become fossil fuel (coal, oil and natural

gas)

Carbon Cycle

Nitrogen Cycle(Nitrogen is required for the manufacture of amino acids and nucleic acids)

1. Reservoir – atmosphere (as

N2); soil (as NH4+ or

ammonium, NH3 or ammonia,

NO2- or nitrite, NO3

- or nitrate)

2. Assimilation – plants absorb

nitrogen as either NH4+ or as

NO3-, animals obtain nitrogen

by eating plants and other

animals.

3. Release – Denitrifying

bacteria convert NO3- back to

N2; detrivorous bacteria

convert organic compounds

back to NH4+ ; animals excrete

NH4+, urea, or uric acid.

Nitrogen Cycle

• N2 in air ( 80% of the atmosphere) organisms cannot use

• Nitrogen fixing bacteria convert N2 into a usable form →plants use to grow

• LEGUMES (beans, alfalfa) nodules contain bacteria that can take atmospheric N2 and convert it to usable nitrogen

• Animals obtain nitrogen from the plants they eat and return it to the soil in their stool.

Nitrogen Cycle

Phosphorus Cycle(Phosphorus is required for the manufacture of ATP and all nucleic acids.)

1.Reservoir – erosion transfers

phosphorus to water and soil;

sediments and rocks that

accumulate on ocean floors return to

the surface as a result of uplifting by

geological processes

2.Assimilation – plants absorb

inorganic PO43- (phosphate) from

soils; animals obtain organic

phosphorus when they plants and

other animals

3.Release – plants and animals

release phosphorus when they

decompose; animals excrete

phosphorus in their waste products *This is the only cycle that does NOT

have an atmospheric component.

Phosphorus Cycle

• Erosion releases phosphorus from rocks into

the surrounding soil

• Phosphate in soil can either:

1) Be used by plants

2) Leach (drain away from soil)

into the water

• Animals receive nutrients by eating the plants

• Decomposers return phosphorus to the soil

• Phosphorus in water will be used by aquatic

plant or settle in sediment that forms new rocks

Phosphorus Cycle

ATP Cycle

• ATP (Adenosine Triphosphate) = The only usable energy form. – To release energy one of the bond between one of

phosphate atoms is broken

– Phosphate is released

– Produces ADP (Adenosine Diphosphate) = the uncharged form

• A phosphate must be added back to the ADP molecule to recharge it and make a new ATP molecule