nitrogen and carbon cycle and their effect on global climate change.

1. Nitrogen and Carbon Cycle
& Their Effect On Global Climate Change.
Submitted To: Dr. Nayan Sahu.
(Department Of Botany)
Indira Gandhi National Tribal University
Amarkantak (M.P)
BOTANY ASSIGNMENT
Submitted By: Priyanka Prakash.
M.sc Botany 2nd Semester
1901217011

2. WHAT IS NITROGEN CYCLE?
•Nitrogen cycle is a cyclic movement of nitrogen in different chemical forms from
environment to organisms and then back to the environment.

4. NITROGEN: A KEY TO LIFE
•Nitrogen (N) is the primary nutrient limiting plant growth throughout the world.
•While 78.08% of the earth’s atmosphere is N, this is not readily available for use by the majority of living organisms, because the N2
molecules do not easily enter into chemical reactions.
•The exception to this is biological Nitrogen fixation, which until the pre-industrial age was the only process where N2 molecules were
converted to reactive N forms, such as ammonium (NH4+ ) and nitrate (NO3-).
•Biological Nitrogen fixation is a process undertaken by bacteria, living in soil or symbiotically within plant root nodules. (However, in
the postindustrial age, reactive N is increasingly being added through manufactured fertilizers, which accounts for more than half of the
annual amount of Nitrogen fixed by human activities (Schlesinger 2009).
•Burning of fossil fuels where the air becomes so hot that the N2 molecules break apart constitutes another anthropogenic-driven Nitrogen
addition to terrestrial ecosystems. The Nitrogen, which is lost from soils in gaseous forms to the atmosphere, can also redistribute across
the landscape via wet and dry deposition.
•A large amount of soil Nitrogen exists in organic forms, which depending upon carbon (C)-to-(N) ratios and the chemical composition of
the soil organic matter can be mineralized by microbes, transforming it into plant available forms, (NH4+) and (NO3-) ( Mineralization
Or Immobilizing The Mineral Nitrogen Forms To Organic Forms (Immobilization).
•During microbially mediated processes of nitrification and denitrification, the reactive Nitrogen is lost from soil as nitrous oxide (N2O),
a powerful greenhouse gas. The Nitrogen cycle is completed through the process of denitrification, in which many soil microorganisms
use (NO3-) as the electron acceptor and return (N2) molecules to the atmosphere, especially under highly anaerobic conditions.
• Losses of reactive Nitrogen from the soil can also occur via leaching as (NO3-), runoff, erosion, and ammonia volatilization.

5. HUMANSALTERATION OF THE NITROGEN CYCLE.
•The contribution to climate change by human-induced changes in the N cycle at
regional and global scales is becoming more widely acknowledged.
•Human activity continue to increase the amount of nitrogen cycling between
the living world and the soil, water, and atmosphere.
•This human driven global change is having serious impacts on ecosystems
around the world because nitrogen is essential to living organisms and its
availability plays a crucial role in the organization and functioning of the
worlds ecosystems.
•In many ecosystems on land and sea, the supply of nitrogen is a key factor
controlling the nature and diversity of the plant life, the population dynamics of
both grazing animals and their predators, the vital ecological processes such as
plant productivity and the cycling of carbon and soil minerals.
•Excessive nitrogen can pollute ecosystems and alter both their ecological
functioning and the living communities they support.
• most of the human activities responsible for the increase in global nitrogen are
in local scale from the production and use of nitrogen fertilizers to the burning
of fossil fuels in automobiles, power generation plants and industries. However,
human activities have not only increased the supply, but also boosted the
global movement of various forms of the nitrogen through air and water.
Because the increase mobility, excess nitrogen from human activities has
serious and long- term environmental consequences for the large regions of the
earth.

6. The impacts of human interference in the nitrogen cycle that have been identified with certainly :
•Increasing temperatures and atmospheric CO2 levels, the two components of climate change, also influence a number of
pathways in the terrestrial N cycle.
For example, an increase in atmospheric temperature leads to significant overall increase in N mineralization and nitrification in
terrestrial ecosystems.
the direct influence of increasing atmospheric CO2 is mainly limited to plant leaves (photosynthesis, stomatal aperture, and
perhaps respiration),
• but there may be indirect effects on soil N transformations, mediated through the changes in the aboveground biomass and
belowground C allocation (Koch and Mooney 1996).
For example, In (2009) observed that gross N mineralization and immobilization were increased in a temperate grassland soil
under elevated CO2 while nitrification was decreased.
•Thus, the effects of climate change on soil N transformations can be complex, and the long-term implications on N retention and
N use efficiency are unclear.
•The application of synthetic N fertilizers together with the development and introduction of rice and wheat cultivars has helped
food production to keep pace with human population growth since the late 1960s. However, excessive use of N fertilizers can
negatively influence soil properties, leading to decreased levels of exchangeable Ca, Mg, and K, reduced effective cation
exchange capacity and acidification of soil, along with increased N leaching and production of N2O.
•Management practices, such as the introduction of legumes into crop rotations, tillage practices, and stubble retention versus
incorporation, also influence N availability and supply in agro-ecosystems, thereby providing significant implications for soil
fertility and the environment.
•Acidification of soils and the waters of streams and lakes in several regions.
•Lakes and other fresh water bodies are routinely face toxic blue-green algae blooms that are filled by nitrogen pollutions.

8. NITROUS OXIDEAND CLIMATE CHANGE
In 2012, nitrous oxide (N2O) accounted for about 6% of all U.S. greenhouse gas
emissions from human activities.
Nitrous oxide is naturally present in the atmosphere as part of the Earth's nitrogen
cycle, and has a variety of natural sources. However, human activities such as
agriculture, fossil fuel combustion, wastewater management, and industrial
processes are increasing the amount of N2O in the atmosphere.
Nitrous oxide molecules stay in the atmosphere for an average of 120 years before
being removed by a sink or destroyed through chemical reactions.
The impact of 1 pound of N2O on warming the atmosphere is over 300 times that
of 1 pound of carbon dioxide. Globally, about 40% of total N2O emissions come
from human activities.
Nitrous oxide is emitted from agriculture, transportation, and industry activities.
1. Agriculture- Nitrous oxide is emitted when people add nitrogen to the soil
through the use of synthetic fertilizers. Agricultural soil management is the
largest source of N2O emissions in the United States, accounting for about
75% of total U.S. N2O emissions in 2012.
• Nitrous oxide is also emitted during the breakdown of nitrogen in livestock
manure and urine, which contributed to 4% of N2O emissions in 2012.

9. 2. Transport- Nitrous oxide is emitted when transportation fuels are burned. Motor vehicles, including passenger cars and
trucks, are the primary source of N2O emissions from transportation. The amount of N2O emitted from transportation
depends on the type of fuel and vehicle technology, maintenance, and operating practices.
3. Industry- Nitrous oxide is generated as a byproduct during the production of nitric acid, which is used to make synthetic
commercial fertilizer, and in the production of adipic acid, which is used to make fibers, like nylon, and other synthetic
products.
• Nitrous oxide (N2O) emissions in the United States have increased by about 3% between 1990 and 2012. This increase
in emissions is due in part to annual variation in agricultural soil emissions and an increase in emissions from the electric
power sector. Nitrous oxide emissions from agricultural soils have varied during this period and were about 9% higher in
2012 than in 1990.
• N2O emissions are projected to increase by 5% between 2005 and 2020, driven largely by increase Nitrous oxide
emissions occur naturally through many sources associated with the nitrogen cycle, which is the natural circulation of
nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water.
• Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including N2O. Natural emissions of N2O
are mainly from bacteria breaking down nitrogen in soils and the oceans.
• Nitrous oxide is removed from the atmosphere when it is absorbed by certain types of bacteria or destroyed by ultraviolet
radiation or chemical reactions. Within the last century, humans have become as important a source of fixed nitrogen as all
natural sources combined.
•Burning fossil fuels, using synthetic nitrogen fertilizers and cultivation of legumes all fix nitrogen. Through these
activities, humans have more than doubled the amount of fixed nitrogen that is pumped into the biosphere every year.

10. CARBON CYCLE

11. CARBON: THE BUILDING BLOCK OF LIFE.
All living things are made of elements, the most abundant of which are, oxygen, carbon, hydrogen, nitrogen, calcium, and
phosphorous. Of these, carbon is the best at joining with other elements to form compounds necessary for life, such as sugars,
starches, fats, and proteins. Together, all these forms of carbon account for approximately half of the total dry mass of living
things.
Carbon is also present in the Earth's atmosphere, soils, oceans, and crust. When viewing the earth as a system, these components
can be referred to as carbon pools (sometimes also called stocks or reservoirs) because they act as storage houses for large
amounts of carbon. Any movement of carbon between these reservoirs is called a flux.
In any integrated system, fluxes connect reservoirs together to create cycles and feedbacks. where, carbon in the atmosphere is
used in photosynthesis to create new plant material.
On a global basis, this processes transfers large amounts of carbon from one pool (the atmosphere) to another (plants).
Over time, these plants die and decay, are harvested by humans, or are burned either for energy or in wildfires. All of these
processes are fluxes that can cycle carbon among various pools within ecosystems and eventually releases it back to the
atmosphere. Viewing the Earth as a whole, individual cycles like this are linked to others involving oceans, rocks, etc. on a range
of spatial and temporal scales to form an integrated global carbon cycle.
•On the shortest time scales, of seconds to minutes, plants take carbon out of the atmosphere through photosynthesis and release it
back into the atmosphere via respiration.
•On longer time scales, carbon from dead plant material can be incorporated into soils, where it might reside for years, decades or
centuries before being broken down by soil microbes and released back to the atmosphere.
•On still longer time scales, organic matter that became buried in deep sediments (and protected from decay) was slowly
transformed into deposits of coal, oil and natural gas, the fossil fuels we use today. When we burn these substances, carbon that
has been stored for millions of years is released once again to the atmosphere in the form of carbon dioxide (CO2)

12. •The carbon cycle has a large effect on the function and well being of our planet.
• Globally, the carbon cycle plays a key role in regulating the Earth’s climate by
controlling the concentration of carbon dioxide in the atmosphere.
•Carbon dioxide (CO2) is important because it contributes to the greenhouse
effect, in which heat generated from sunlight at the Earth’s surface is trapped by
certain gasses and prevented from escaping through the atmosphere.
• The greenhouse effect itself is a perfectly natural phenomenon and, without it,
the Earth would be a much colder place. But as is often the case, too much of a
good thing can have negative consequences, and an unnatural buildup of
greenhouse gasses can lead to a planet that gets unnaturally hot. In recent years
CO2 has received much attention because its concentration in the atmosphere
has risen to approximately 30% above natural background levels and will
continue to rise into the near future. Scientists have shown that this increase is a
result of human activities that have occurred over the last 150 years, including
the burning of fossil fuels and deforestation.
• Because CO2 is a greenhouse gas, this increase is believed to be causing a rise
in global temperatures. This is the primary cause of climate change and is the
main reason for increasing interest in the carbon cycle.
CARBON AND CLIMATE CHANGE

13. CARBON POOLS
Depending on our goals, the Earth’s carbon pools can be grouped into any number of different
categories.
1. The Earth’s Crust: The largest amount of carbon on earth is stored in sedimentary rocks within the
planet’s crust. These are rocks produced either by the hardening of mud (containing organic matter)
into shale over geological time, or by the collection of calcium carbonate particles, from the shells
and skeletons of marine organisms, into limestone and other carbon containing sedimentary rocks.
2. Oceans: Most of the carbon present in the earth’s ocean is in the form of dissolved inorganic carbon
stored at great depths where it resides for long periods of time. A much smaller amount of carbon, is
located near the ocean surface. This carbon is exchanged rapidly with the atmosphere through both
physical processes, such as CO2 gas dissolving into the water, and biological processes, such as the
growth, death and decay of plankton. Although most of this surface carbon cycles rapidly, some of
it can also be transferred by sinking to the deep ocean pool where it can be stored for a much longer
time.
3. Atmosphere: The carbon present in the atmosphere is in the form of CO2, with much smaller
amounts of methane (CH4) and various other compounds. Although this is considerably less carbon
than that contained in the oceans or crust, carbon in the atmosphere is of vital importance because
of its influence on the greenhouse effect and climate. The relatively small size of the atmospheric
carbon pool also makes it more sensitive to disruptions caused by an increase in sources or sinks of
carbon from the Earth’s other pools. In the context of global pools and fluxes, the increase that has
occurred in the past several centuries is the result of carbon fluxes to the atmosphere from the crust
(fossil fuels) and terrestrial ecosystems (via deforestation and other forms of land clearing).
4. Terrestrial Ecosystems: It contains carbon in the form of plants, animals, soils and
microorganisms (bacteria and fungi). Of these, plants and soils are by far the largest and, when
dealing with the entire globe, the smaller pools are often ignored. Unlike the Earth’s crust and
oceans, most of the carbon in terrestrial ecosystems exists in organic forms. In this context, the term
“organic” refers to compounds produced by living things, including leaves, wood, roots, dead plant
material and the brown organic matter in soils (which is the decomposed remains of formerly living
tissues). Plants exchange carbon with the atmosphere relatively rapidly through photosynthesis, in
which CO2 is absorbed and converted into new plant tissues, and respiration, where some fraction
of the previously captured CO2 is released back to the atmosphere as a product of metabolism.

14. CARBON FLUXES
The movement of any material from one place to another is called a flux. A single
carbon pool can often have several fluxes both adding and removing carbon
simultaneously. For example, the atmosphere has inflows from decomposition (CO2
released by the breakdown of organic matter), forest fires and fossil fuel combustion and
outflows from plant growth and uptake by the oceans. The size of various fluxes can
vary widely.
1. Photosynthesis: During photosynthesis, plants use energy from sunlight to
combine CO2 from the atmosphere with water from the soil to create
carbohydrates. In this way, CO2 is removed from the atmosphere and stored in the
structure of plants. Virtually all of the organic matter on Earth was initially formed
through this process. When plants die, their tissues remain for a wide range of time
periods. Tissues such as leaves, which have a high quality for decomposer
organisms, tend to decay quickly, while more resistant structures, such as wood can
persist much longer.
2. Plant Respiration: Plants also release CO2 back to the atmosphere through the
process of respiration (the equivalent for plants of exhaling). Respiration occurs as
plant cells use carbohydrates, made during photosynthesis, for energy. Plant
respiration represents approximately half of the CO2 that is returned to the
atmosphere in the terrestrial portion of the carbon cycle.
3. Litterfall: In addition to the death of whole plants, living plants also shed some
portion of their leaves, roots and branches each year. Because all parts of the plant
are made up of carbon, the loss of these parts to the ground is a transfer of carbon
(a flux) from the plant to the soil.
4. Soil Respiration: The release of CO2 through respiration is not unique to plants,
but is something all organisms do, including microscopic organisms living in soil.
Because it can take years for a plant to decompose (or decades in the case of large
trees), carbon is temporarily stored in the organic matter of soil.

15. 5. Ocean-Atmosphere exchange: Inorganic carbon is absorbed and released at the interface of the ocean’s surface and
surrounding air, through the process of diffusion. The formation of carbonate in seawater allows oceans to take up and store a
much larger amount of carbon than would be possible if dissolved CO2 remained in that form. Carbonate is also important to
a vast number of marine organisms that use this mineral form of carbon to build shells. Carbon is also cycled through the
ocean by the biological processes of photosynthesis, respiration, and decomposition of aquatic plants.
6. Fossil fuel combustion and land cover change: The carbon fluxes discussed thus far involve natural processes that have
helped regulate the carbon cycle and atmospheric CO2 levels for millions of years. However, the modern-day carbon cycle
also includes several important fluxes that stem from human activities. The most important of these is combustion of fossil
fuels: coal, oil and natural gas. These materials contain carbon that was captured by living organisms over periods of millions
of years and has been stored in various places within the Earth's crust.
7. Geological Processes: Rocks on land are broken down by the atmosphere, rain, and groundwater into small particles and
dissolved materials, a process known as weathering. These materials are combined with plant and soil particles that result
from decomposition and surface erosion and are later carried to the ocean where the larger particles are deposited near shore.
Slowly, these sediments accumulate, burying older sediments below. The layering and burial of sediment causes pressure to
build, which eventually becomes so great that deeper sediments are turned into rock, such as shale. Within the ocean water
itself, dissolved materials mix with seawater and are used by marine life to make calcium carbonate (CaCO3) skeletons and
shells. When these organisms die, their skeletons and shells sink to the bottom of the ocean. In shallow waters (less than 4km)
the carbonate collects and eventually forms another type of sedimentary rock called limestone.

16. Nature absorbs 788 billion tonnes of carbon every year. Natural absorptions roughly balance natural emissions. Humans upset this balance. While some of
ourhuman-producedcarbondioxideemissionsarebeingabsorbedby theoceanandlandplants,aroundhalfofourcarbondioxideemissionsremaininthe
air.
1. Carbon sequestration: The uptake and storage of
carbon. Trees and plants, for example, absorb carbon
dioxide, release the oxygen and store the carbon.
2. Carbon sink: A carbon reservoir that takes in and
stores more carbon than it releases. It can serve to
partially offset greenhouse gas emissions. Forests and
oceans are both large carbon sinks.
3. Global warming: A popular term used to describe the
increase in average global temperatures due to the
greenhouse effect. It is often used interchangeably
with the term climate change.
4. Greenhouse effect: A popular term used to describe
the roles of water vapor, carbon dioxide, methane, and
other gases (greenhouse gases - GHG) in keeping the
Earth's surface warmer than it would be otherwise.
How Much Carbon Humans Emit?

17. The warming of global temperatures also in changing which ecosystems act as long-term sinks for carbon and which acts as
sources for carbon dioxide in the atmosphere.
The complex cycle of carbon and varying sizes of carbon reservoirs illustrate some of the reasons it has been so difficult to
predict the effects that increased atmospheric carbon will have on global change.
The increase in carbon dioxide directly increases plant photosynthesis, but the size of the increase depends on the species and
physiological condition of the plant.
Furthermore, if increasing levels of atmospheric carbon dioxide result in climatic changes, including increased global
temperatures as some meteorologists predicts these change will affect photosynthesis rates.
Carbon is a key element of all life on earth, has complicated biogeochemical cycle of great importance to global climate change.
It is necessary to understand the environmental significance of this cycles for protecting the environment and sustenance of life
on earth.
Thank You

18. REFERENCES
1. https://esrl.noaa.gov Nitrogen And Climate Change
2. http://www.researchgate.net The Role Of Nitrogen In Climate Change And The Impacts Of nitrogen
3. http://www.researchgate The Nitrogen Cycle: Implications For Management, Soil, Health, And Climate Change
4. http://e360.yale.edu The Nitrogen Problem: Why Global Warming Is Making It Worse.
5. http://eos.org The Future Of The Carbon Cycle In A Changing Climate
6. http://www.sciencedirect.com The Global Nitrogen Cycle: Changes And Consequences
7. http://www.slideshare.net Carbon Cycle And Global Concern On Environment.
8. http://www.slideshare.net Global Carbon Cycle
9. Images from google.