Chemistry presentation1

7/29/2019 Chemistry presentation1

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Carbon and Nitrogen

CyclePROUDLY PRESENT BY ,

MD ADIB FIKRIKAVISYA

LOGADHARSHINISUGANEYAALKHALWARIZMI


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Aim: To explore the carbon and nitrogencycles

Objectives

Describe how energy flows in an ecosystem

Illustrate the carbon and nitrogen cycles

Explain how human activity is affecting carbon

emissions


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INTRODUCTION

Additions of reactive nitrogen to terrestrialecosystems primarily through fertilizer application

and atmospheric deposition have more than doubled

since 1860 owing to human activities.

Nitrogen additions tend to increase the net uptake of

carbon by the terrestrial biosphere, but they also

stimulate nitrous oxide release from soils.

However, given that the magnitude of these effectsis uncertain, and that the carbon and nitrogen cycles

are tightly coupled, the net climatic impact of

anthropogenic nitrogen inputs is unknown


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Trophic Levels

Energy moves from one organisms to another

when it is eaten

Each step in this transfer of energy is known as

a trophic level

The main trophic levels are producers and consumers


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Food Chains

The energy flow from one trophic level to theother is know as a food chain

A simple food chain shows how energy istransferred from the sun through livingorganisms.

It involves one organism at each trophic level Producers (e.g. plants) Primary Consumers

Secondary Consumers

Tertiary Consumers


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Food Chain


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Food Web

Most animals eat more than JUST one organism

So in any ecosystem food chains connect toform a food web

Food webs are more complex and involve lots oforganisms


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Food web

TREES produce ACORNS which

act as food for many MICE andINSECTS.

Because there are many MICE,WEASELS and SNAKES havefood.

The insects and the acorns also

attract BIRDS, SKUNKS, andOPOSSUMS.

With the SKUNKS, OPPOSUMS,WEASELS and MICE around,HAWKS, FOXES, and OWLS canfind food.

They are all connected! Like aspiders web, if one part isremoved, it can affect the wholeweb.


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Ecological Pyramid

At each trophic level energy is used and

waste material produced

So there is less energy available for transfer

at each stage and a food pyramid is formed


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Carbon cycle

The circulation of carbon atoms in the

biosphere as a result of photosynthetic

conversion of carbon dioxide into complex

organic compounds by plants, which areconsumed by other organisms

The carbon returns to the atmosphere in

the form of carbon dioxide as a result ofrespiration, decay by fungi, bacteria, and

combustion of fossil fuels.


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AtmosphericCarbon Dioxide


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Plants use carbondioxide to make theirfood (photosynthesis)


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Green plants areeaten byanimals


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Green plants areeaten byanimals

respiration


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green plants areeaten byanimals

respiration

dead remains of plants andanimals


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Plants use carbondioxide to make theirfood (photosynthesis

green plants areeaten byanimals

respiration

dead remains of plantsand animals

decayby fungiand bacteria


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Carbon in Oceans

Additional carbon is stored in the ocean.

Many animals pull carbon from water to use in

shells, etc.

Animals die and carbon substances are

deposited at the bottom of the ocean.

Oceans contain earths largest store of carbon.


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Human Impact

Fossil fuels release carbon stores very slowly

Burning anything releases more carbon intoatmosphere especially fossil fuels

Increased carbon dioxide in atmosphereincreases global warming

Fewer plants mean less CO2 removed fromatmosphere


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21


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Greenhouse Gases

The greenhouse effect is causing the

Earth to warm up.

This is causing climate change

and melting of the polar icecaps, this could lead toflooding.

It is due to increasing amounts ofgreenhouse gases, such as carbondioxide, water vapour andmethane.

Burning fuels is a majorcause of this increase.

Video
http://www.youtube.com/watch?v=dP-tg4atr5M&feature=relatedhttp://www.youtube.com/watch?v=dP-tg4atr5M&feature=related


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Nitrogen cycle

The nitrogen cycle is the process by which nitrogen is

converted between its various chemical forms. This

transformation can be carried out through both biological

and physical processes.

Important processes in the nitrogen cycle

include fixation, ammonification, nitrification,

and denitrification.

The majority of Earth's atmosphere (78%) is nitrogen,

making it the largest pool of nitrogen. However,atmospheric nitrogen has limited availability for biological

use, leading to a scarcity of usable nitrogen in many types

of ecosystems.


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( )


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Denitrifyingbacteria

Nitrates(NO3

)Detritivores

Ammonium (NH4+)

Amino acidsand proteins in

plants and animals

Detritus

Assimilationby plants

Nitrogen-fixingbacteria in soil

Nitrogenfixation

Decomposition

Nitrogen-fixingbacteria in root

nodules of legumes

Nitrogenfixation

Nitrogen (N2) in atmosphere


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There are 4 phases in the cycle:

Nitrogen fixation = NH3/NH4+

Decay = decomposing organic nitrogen into NH4+

Nitrification = converting NH4+ to NO2 to NO3

Denitrification = converting NO3 into N2

Micro-organisms play an important part in this cycle!


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Nitrogen Fixation

The enormous energy oflightning breaks nitrogen moleculesapart and enables the nitrogen atoms to combine withoxygen forming nitrogen oxides (N2O)

Nitrogen oxides dissolve in rain, forming nitrates (NO3)

Nitrates(NO3) are carried to the ground with the rain.

NN O

(NO3)

(N2O)
http://www.specialedprep.net/MSAT%20SCIENCE/Images/Nitriteion.jpg


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Lightning fixes Nitrogen!

Nitrogen combineswith Oxygen

Nitrogen oxides forms

Nitrogen oxidesdissolve in rain andchange to nitrates

Plants use nitrates

to grow!

(NO3)

NN O

(N2O)
http://www.specialedprep.net/MSAT%20SCIENCE/Images/Nitriteion.jpg


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Decay

Animals acquire their amino acids when they eat

plants.

When animals and plants die their remains areused as food by micro-organisms such as bacteria

and fungi.

Decomposers convert the nitrogen back intoammonia (NH3)

Ammonia (NH3) is

stored in soil.

Decomposers convert organic nitrogen toammonia (NH3) Ammonia (NH3) is used by some

plants


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Nitrifying bacteria in soil combineammonia with oxygen

Ammonia changes to nitrites

Nitrifying bacteria in soil convertnitrites to nitrates

Plants absorb nitrates and

grow!

Ammonia Nitrites Nitrates

(NH3) (NO3)(NO2)

Nitrification Living in the soil are nitrifying bacteria.

First, Nitrosomonas bacteria combine ammonia with oxygen toform nitrites.

Then another group of nitrifying bacteria, Nitrobacter, convertnitrites to nitrates which green plants can absorb and use!


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Figure 32.13

ATMOSPHERE

N2

N2 Nitrogen-fixingbacteria

Ammonifyingbacteria

Organicmaterial

NH4+

(ammonium) Nitrifyingbacteria

NO3

(nitrate)

Root

NH4+

Aminoacids

Soil


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Denitrification

Denitrification converts nitrates (NO3) in the soil to

atmospheric nitrogen (N2) which is returned to the air.

Denitrifying bacteria live deep in soil and in aquatic

sediments where conditions make it difficult for them to get

oxygen

Denitrifying bacteria live deepin soil and use nitrates as analternative to oxygen making abyproduct of nitrogen gas.

Nitrogen in atmospherecloses the nitrogen cycle!

(NO3) (N2)


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Acid Rain

Human activity havedoubled the amount offixed nitrogen entering thenitrogen cycle in just 100

years

Manufacture and use of

nitrogen fertilisers,combustion of fossilfuels and forest burning

Kills fish, damages trees andbuildings.

Video

Climate change, acidrain, the acidification of

soils and loss of soilnutrients, and theacidification of streamsand lakes.
http://www.youtube.com/watch?v=HE6Y0iEuXMQhttp://www.youtube.com/watch?v=HE6Y0iEuXMQ


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Effects of Nitrogen Overload

Effects on soil makes soil acidicdissolving toxic metals such as aluminium.

Effects on the atmosphere acid

precipitation killing many organisms

Effects on fresh-water ecosystems

eutrophication and algal bloom.


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Thank You !!!!

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Chemistry presentation1