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Nutrient Cycles in the Ecosystem



Learning ObjectivesLearning Objectives

You will learn about the need for the recycling of nutrients

trapped in living things about the part played by decomposers in

recycling processes about the carbon and nitrogen cycles how the carbon and nitrogen cycles help to

maintain a balance in the ecosystem



15.1 Round and Round - Recycling

15.1 Round and Round - Recycling

Definition:Definition:

Recycling meansµto use again¶.

What is Recycling???What is Recycling???

People are encouraged to recycle resources becausenatural resources are limited. Recycling also occursin nature.



Definition:Definition:Organisms that feed on dead plants and animals arecalled decomposers.

Decomposers (such as fungi, ants and bacteria)bring about decay or breakdown of dead plants andanimals into smaller substances. Some are eatenwhile others are returned to the soil or the waterwhere they are reused by plants. Carbon dioxide andother gases are also released into the air.

What are

Decomposers???

What are

Decomposers???

DecomposersDecomposers



15.2 Cycling of Materials

15.2 Cycling of Materials

atter that makes up animals andplants moves in a cycle. A cycle is aseries of changes that lead back to

the starting point.

Matter that makes up animals andplants moves in a cycle. A cycle is aseries of chang

es that lead back to

the starting point.



The Carbon CycleThe Carbon Cycle

Carbon is an important element in living things. Itis part of the proteins, carbohydrates and fats inthe tissues of living things.

The circulation of carbon through the ecosystem is

called the carbon cycle.

Carbon is an important element in living things. Itis part of the

proteins, carbohydrates and fats inthe tissues of living things.

The circulation of carbon through the ecosystem is

called the carbon cycle.

Removal of CO2 from Air Inclusion of CO2 into Air

during photosynthesis, greenplants take in CO2 to makestarch (a carbohydrate)

seas and oceans serve as sinkswhen CO2 dissolves

during respiration, all livingthings release CO2

when decomposers break downdead organisms, CO2 isreleased from the dead matter



Processes involvingcarbon in the ecosystem.Processes involvingcarbon in the ecosystem.

Two important roles: ensures that CO2 and

other carboncompounds do notmove out and arealways available forliving things to use

helps to keep theamount of carbon inthe ecosystemconstant so thatthere is neither toomuch or too little

Two important roles: ensures that CO2 and

other carboncompounds do notmove out and arealways available forliving things to use

helps to keep theamount of carbon inthe ecosystemconstant so thatthere is neither toomuch or too little

The Carbon CycleThe Carbon Cycle

photosynthesis in

green plants

respiration by

living things

feed

carboncompounds

in plants

carboncompounds

in animals

death

decay of dead

matter by

decomposition



Nitrogen is also an essential element in livingthings. It is needed to make proteins that are usedfor the growth of tissue.

The circulated nitrogen through the ecosystem is

called the nitrogen cycle.

Nitrogen is also an essential element in livingthings. It is needed to make proteins that are usedfor the growth of tissue.

The circulated nitrogen through the ecosystem is

called the nitrogen cycle.

The Nitrogen CycleThe Nitrogen Cycle

Removal of Nitrogen from Soil Inclusion of Nitrogen into Soil

plants absorb the nitrogencompounds through their rootsand use them to make proteins;

animals get proteins by feedingon plants and other animals

certain kinds of bacteria in thesoil are able to change nitrogencompounds into nitrogen gas

proteins in dead plants andanimals are broken down intosimple nitrogen compounds bydecomposition, and released to

the soil

bacteria in the soil or fromroots of some plants producesimple nitrogenous compoundsby acting upon animal wastesor the air




Processes involvingnitrogen in the ecosystem.Processes involvingnitrogen in the ecosystem.

Two important roles: ensures that the

rate of addingnitrogencompounds to thesoil is equal to therate of removingthem

keeps the nitrogen

compounds at aconstant level sothat they do notrun out

Two important roles: ensures that the

rate of addingnitrogencompounds to thesoil is equal to therate of removingthem

keeps the nitrogen

compounds at aconstant level sothat they do notrun out

bacteria

in root

nodules

nitrogen in the air

waste

nitrogen compounds

in the soil

death

feeding

nitrogen

compounds

in plants

nitrogen

compounds

in animals

decay by

bacteriaabsorbed by

plant roots

decay by

bacteria

bacteria in

soil

bacteria in

soil




When growing crops, naturalmethods do not always add nitrogencompounds (also called fertilizers)

to the soil fast enough. Thereforeartificial methods are used forcreating fertilizers.

Nitrogen from the air is convertedinto ammonia by a process calledthe Haber process.

When growing crops, naturalmethods do not always add nitrogencompounds (also called fertilizers)

to the soil fast enough. Thereforeartificial methods are used forcreating fertilizers.

Nitrogen from the air is convertedinto ammonia by a process calledthe Haber process.

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