CYCLES OF MATTER

NATURAL WORLD

Objectives

• Describe how matter cycles between the livingand nonliving parts of an ecosystem.

• Explain why nutrients are important in livingsystems.

• Describe how the availability of nutrients affectsthe productivity of ecosystems.

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Vocabulary

Biogeochemical CycleEvaporationTranspirationNutrientsNitrogen FixationDenitrificationPrimary ProductivityLimiting NutrientAlgal Bloom

Recycling in the Biosphere

Unlike the one-way flow of energy, matter isrecycled within and between ecosystems.

Matter can be recycled, because biological systems donot use up matter, they only change it from one form toanother.

The Water Cycle

The water cycle involves the movement of waterbetween the ocean, atmosphere, and land.

Evaporation is process by which water changesfrom liquid form to atmospheric gas.

Transpiration is the process of water enteringthe atmosphere by evaporating from the leaves ofplants.

The Water Cycle

Most of the water on Earth is held in the ocean.The sun causes the water to evaporate. As thewater vapor cools it condenses into droplets.When the droplets become large enough theyreturn to the Earth’s surface. On land, much ofthe precipitation runs along the surface until itenters a river or stream that carries the runoffback to an ocean or lake. Water can enter plantsthrough their roots. The water cycle begins allover again.

Nutrient Cycles

Nutrients include all the chemical substancesthat an organism requires to live. Every organismneeds nutrients to grow and carry out essentiallife functions. Like water nutrients are passedbetween organisms through cycles.

The three nutrient cycles that play especiallyprominent roles in the biosphere are the carboncycle, the nitrogen cycle, and the phosphorus cycle.

The Carbon Cycle

Carbon is the key ingredient in all livingorganisms. Carbon is also found in the oceans, inthe air, and in certain types of rocks.

Scientists believe the Earth contains approximately49,000 gigatons of carbon. However, less than 1percent actively circulates within the biosphere. 71% isin the oceans, 22% in fossils, 3% in dead organicmatter, and 3% in terrestrial ecosystems.

Carbon Cycle

There are four different kinds of processes involvedin the carbon cycle…1.

2.

3.

4.

Biological

Geochemical

Biogeochemical

Human Impact

Biological Processes

Carbon in the atmosphere is carbon dioxide.

Plants take in carbon dioxide and use the carbonto build carbohydrates during photosynthesis.

The carbohydrates are passed along the foodweb to the consumers.

The carbohydrates are broken down by animalsduring respiration and returned to the atmosphereas carbon dioxide.

Geochemical Processes

Carbon Dioxide gas is released into theatmosphere by erupting volcanoes.

Biogeochemical Processes

These are caused by the burial of carbon-richremains of organisms and their conversion intocoal and petroleum (fossil fuels) by the pressureof 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 ofnitrate - a major component of plant fertilizers.

Nitrogen Cycle

Only certain types of nitrogen-fixing bacteria can use thegasseous form of nitrogen (N2).Nitrogen Fixation is when nitrogen-fixing bacteriaconvert atmospheric nitrogen into ammonia.

Nitrogen-fixing bacteria live in the soil, and on theroots of plants called legumes (bean plants).

Nitrogen Cycle

Producers can use the nitrogen in the soil tomake proteins. Consumers eat the producersand reuse the nitrogen to make their ownproteins. When organisms die decomposersreturn nitrogen to the soil as ammonia. Some ofthe ammonia will be taken up again by producers.Denitrification, other soil bacteria will convert thenitrates 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 organismsbecause it forms part of important life-sustainingmolecules DNA and RNA.

Inorganic phosphate makes up the the backbone ofDNA and RNA, the molecules of heredity.

Phosphorus Cycle

Phosphorus does not enter the atmosphere. Itremains mostly in the rocks, soil and the ocean

as its inorganic form (Pi).

Phosphorus Cycle

When plants absorb phosphate from the soil orfrom water, the plants bind the phosphate intoorganic compounds. Organic phosphate travelsthrough the food web.

Organic compounds are defined as compounds thatcontain 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.