CYCLES OF MATTER

NATURAL WORLD

Objectives

• Describe how matter cycles between the living

and nonliving parts of an ecosystem.

• Explain why nutrients are important in living

systems.

• Describe how the availability of nutrients affects

the productivity of ecosystems.

Vocabulary

• Biogeochemical Cycle

• Evaporation

• Transpiration

• Nutrients

• Nitrogen Fixation

• Denitrification

• Primary Productivity

• Limiting Nutrient

• Algal Bloom

Recycling in the Biosphere

Unlike the one-way flow of energy, matter is

recycled within and between ecosystems.

Matter can be recycled, because biological systems do

not use up matter, they only change it from one form to

another.

The Water Cycle

The water cycle involves the movement of water

between the ocean, atmosphere, and land.

Evaporation is process by which water changes

from liquid form to atmospheric gas.

Transpiration is the process of water entering

the atmosphere by evaporating from the leaves of

plants.

The Water Cycle

Most of the water on Earth is held in the ocean.

The sun causes the water to evaporate. As the

water vapor cools it condenses into droplets.

When the droplets become large enough they

return to the Earth’s surface. On land, much of

the precipitation runs along the surface until it

enters a river or stream that carries the runoff

back to an ocean or lake. Water can enter plants

through their roots. The water cycle begins all

over again.

Nutrient Cycles

Nutrients include all the chemical substances

that an organism requires to live. Every organism

needs nutrients to grow and carry out essential

life functions. Like water nutrients are passed

between organisms through cycles.

The three nutrient cycles that play especially

prominent roles in the biosphere are the carbon

cycle, the nitrogen cycle, and the phosphorus cycle.

The Carbon Cycle

Carbon is the key ingredient in all living

organisms. Carbon is also found in the oceans, in

the air, and in certain types of rocks.

Scientists believe the Earth contains approximately

49,000 gigatons of carbon. However, less than 1

percent actively circulates within the biosphere. 71% is

in the oceans, 22% in fossils, 3% in dead organic

matter, and 3% in terrestrial ecosystems.

Carbon Cycle

There are four different kinds of processes involved

in the carbon cycle…

1. Biological

2. Geochemical

3. Biogeochemical

4. Human Impact

Biological Processes

Carbon in the atmosphere is carbon dioxide.

Plants take in carbon dioxide and use the carbon

to build carbohydrates during photosynthesis.

The carbohydrates are passed along the food

web to the consumers.

The carbohydrates are broken down by animals

during respiration and returned to the atmosphere

as carbon dioxide.

Geochemical Processes

Carbon Dioxide gas is released into the

atmosphere by erupting volcanoes.

Biogeochemical Processes

These are caused by the burial of carbon-rich

remains of organisms and their conversion into

coal and petroleum (fossil fuels) by the pressure

of the overlying earth.

Human Impact

Humans affect the carbon cycle by mining,

burning fossil fuels, and destroying forests.

Carbon Cycle

CO2 inAtmosphere

CO2 in Ocean

STOP HERE

End of cycles day one

Nitrogen Cycle

All organisms require nitrogen to make amino acids,

which in turn are used to build proteins.

Nitrogen gas (N2) makes up 78% of our atmosphere.

Nitrogen-containing substances such as ammonia (NH3),

nitrates (NO3-), and nitrites (NO2

-) are found in dead and

decaying organic matter.

Humans add nitrogen to the biosphere in the form of

nitrate - a major component of plant fertilizers.

Nitrogen Cycle

Only certain types of nitrogen-fixing bacteria can use the

gasseous form of nitrogen (N2).

Nitrogen Fixation is when nitrogen-fixing bacteria

convert atmospheric nitrogen into ammonia.

Nitrogen-fixing bacteria live in the soil, and on the

roots of plants called legumes (bean plants).

Nitrogen Cycle

Producers can use the nitrogen in the soil to

make proteins. Consumers eat the producers

and reuse the nitrogen to make their own

proteins. When organisms die decomposers

return nitrogen to the soil as ammonia. Some of

the ammonia will be taken up again by producers.

Denitrification, other soil bacteria will convert the

nitrates into nitrogen gas (N2) returning it to the

atmosphere.

Nitrogen Cycle

N2 in Atmosphere

NH3

NO3-

and NO2-

Phosphorus Cycle

Phosphorus is essential to living organisms

because it forms part of important life-sustaining

molecules DNA and RNA.

Inorganic phosphate makes up the the backbone of

DNA and RNA, the molecules of heredity.

Phosphorus Cycle

Phosphorus does not enter the atmosphere. It

remains mostly in the rocks, soil and the ocean

as its inorganic form (Pi).

Phosphorus Cycle

When plants absorb phosphate from the soil or

from water, the plants bind the phosphate into

organic compounds. Organic phosphate travels

through the food web.

Organic compounds are defined as compounds that

contain carbon.

Nutrient Limitation

Primary Productivity is the rate at which organicmatter is created by producers.

A Limiting Nutrient when a nutrient is in shortsupply and it limits the growth of the ecosystem.

Algal Bloom when an aquatic ecosystemreceives a large input of a limiting nutrient itresults in a rapid growth of algae.