The document discusses the processes of decomposition and biogeochemical cycles, highlighting how decomposers like bacteria and fungi break down organic matter, and detailing the roles of the nitrogen, carbon, and oxygen cycles. It explains the stages of each cycle, their significance to ecosystems, and the factors affecting them, such as deforestation and land development. These cycles are essential for nutrient recycling and maintaining environmental balance.

1. DECOMPOSITION
BIOGEOCHEMICAL
CYCLES
AND
Noemi T. Pamintuan Principles of Ecology
2022 Nov. 19

2. 3
DECOMPOSITION
means “to break down”
It is the process by which bacteria and fungi
break dead organisms into their simple
compounds.
Decomposers are organisms that break down dead
or decaying organisms.
Examples: Bacteria, Fungi, Earthworms
Detritus is the raw material or organic matter
produced by the decomposition of organisms
Examples: Dead animals, plants and their remains

3. 1.FRAGMENTATION
2. LEACHING
3. CATABOLISM
4. HUMIFICATION
5. MINERALIZATION
3
PROCESS OF DECOMPOSITION
breakdown of detritus into smaller
pieces by the detritivores.
the process of releasing nutrients in
the water and seeping into the soil.
the process of breaking down complex
molecules into simpler molecules
the process of formation of a dark-
colored layer of amorphous substance
on the soil called humus
the process of the degradation of the
hummus to release inorganic nutrients.

4. A green leaf falls on the ground
Some nutrients leach into
the soil by chemical action
Leaves partially consumed by
decomposers such as fungi and
bacteria begin to lose form and
become litter.
Some are eaten by insects
and other animals
Further decomposition by
earthworms, bacteria, soil
mites, fungi etc.
4
A tee grows in the soil
Organic Rich Soil

5. 3
BIOGEOCHEMICAL CYCLES
The term biogeochemical is derived
from “bio” meaning biosphere, “geo”
meaning the geological components and
“chemical” meaning the elements that
move through a cycle.
A biogeochemical cycle is the process
of moving or rotation of matter
throughout the biotic and the abiotic
spheres of the ecosystem.
Biogeochemical cycles are basically divided
into two types:
Gaseous cycles – Includes Carbon,
Oxygen, Nitrogen, and the Water cycle.
Sedimentary cycles – Includes Sulphur,
Phosphorus, calcium, iron cycle etc.
Water Cycle
Nitrogen Cycle
Oxygen Cycle
Carbon Cycle
Major Cycles

6. WATER CYCLE or "Hydrologic cycle"
This biogeochemical cycle is responsible for maintaining weather conditions.
This cycle describes the continuous movement of water on, above and below the surface of the Earth.
Moves things like nutrients, pathogens and sediment in and out of aquatic ecosystems.
Stages of Water Cycle
Evaporation
1.
The process that changes liquid water to gaseous
water
Sublimation
2.
Conversion of a substance from the solid to the
gaseous state without its becoming liquid (Ice to
Gas)
Condensation
3.
Conversion of a vapor or gas to a liquid
Precipitation
4.
Water that falls from the clouds towards the
ground as a result of condensation in the
atmosphere
Includes rain, snow, or hail
Infiltration
5.
Happens when water soaks into the soil from the
ground level
Runoff
6.
Occurs when there is more water than land can
absorb.
Includes snowmelt that turns into streams, rivers,
and lakes

7. WATER CYCLE or "Hydrologic cycle"
Construction of roads and buildings.
Cutting down of trees. Water withdrawals or impoundments through wells or dams
Filling wetlands,
Ways in which the Water Cycle is affected

8. OXYGEN CYCLE
The process which helps in maintaining the oxygen level by moving through three main spheres of the earth which are:
Atmosphere, Lithosphere, and Biosphere.
The oxygen cycle is interconnected with the carbon cycle.
Stages in the Oxygen Cycle
Stage-1: Green plants during the process of
photosynthesis, release oxygen back into the atmosphere
as a by-product.
Photosynthesis – a biological process by which all
green plants, with the help of sunlight, water, and
carbon dioxide, synthesize their food to create energy
and oxygen gas which is liberated as a by-product of
this process.
Sunlight – also produces oxygen when it reacts with
water vapor in the atmosphere
Stage-2: Aerobic organisms use free oxygen for
respiration.
Stage-3: Animals exhale Carbon dioxide back into the
atmosphere which is again used by the plants during
photosynthesis.

9. OXYGEN CYCLE
Uses of Oxygen:
Rusting
1.
Oxygen is used on rusting when metals are exposed to
moisture and oxygen for an extended period of time.
Decomposition
2.
Dead organisms decay into the ground and other
organic matter along with carbon, oxygen, water and
other components are returned in the soil and air.
Combustion
3.
Occurs when any organic materials are burned in the
presence of oxygen
Breathing
4.
All living organisms inhale oxygen and exhale carbon
dioxide from the outside environment.
Ways in which the Oxygen cycle is affected
Use of Fossil Fuels Use or change of Land

10. NITROGEN CYCLE
The process through which nitrogen is converted into many
forms, consecutively passing from the atmosphere to the soil
to organism and back into the atmosphere.
Stages in the Nitrogen Cycle:
Nitrogen Fixation
1.
Converts nitrogen in the atmosphere into forms that
plants can absorb through their root systems
Mineralization
2.
Nitrogen moves from organic materials, such as manure
or plant materials to an inorganic form of nitrogen that
plants can use
a.
Nitrification
3.
Ammonia in the soils, produced during mineralization, is
converted into compounds called nitrites
Immobilization
4.
Described as the reverse of mineralization; helps control
and balance the amount of nitrogen in the soils by
immobilizing the nitrogen, in microorganisms.
Denitrification
5.
Nitrogen returns to the air as nitrates are converted to
atmospheric nitrogen

11. Importance of Nitrogen Cycle
Helps plants to synthesize chlorophyll from the nitrogen compounds.
Helps in converting inert nitrogen gas into a usable form for the plants through the biochemical process.
In the process of ammonification, the bacteria help in decomposing the animal and plant matter, which indirectly helps to clean up the
environment.
Nitrates and nitrites are released into the soil, which helps in enriching the soil with the necessary nutrients required for cultivation.
Nitrogen is an integral component of the cell and it forms many crucial compounds and important biomolecules.
NITROGEN CYCLE
Burning fossil fuels Application of nitrogen-based fertilizers Intensive cultivation
Ways in which the Nitrogen Cycle is affected

12. CARBON CYCLE
The process in which carbon atoms continually travel from
the atmosphere to the Earth and then back into the
atmosphere.
It balances the energy and traps the long-wave radiations
from the sun.
Carbon
the chemical backbone of life on Earth
regulate the Earth’s temperature, make up the food that
sustains us, and provide energy that fuels our global
economy
Stages of the Carbon Cycle:
Carbon present in the atmosphere is absorbed by plants
for photosynthesis.
1.
These plants are then consumed by animals and carbon
gets bioaccumulated into their bodies.
2.
These animals and plants eventually die, and upon
decomposing, carbon is released back into the
atmosphere.
3.
Some of the carbon that is not released back into the
atmosphere eventually become fossil fuels.
4.
These fossil fuels are then used for man-made activities,
which pump more carbon back into the atmosphere.
5.

13. CARBON CYCLE
Burning of fossil fuels
Use or Change of Land
Using limestone to make concrete
Cutting down of trees.
Ways in which the Carbon Cycle is affected

14. Cases: Cutting down of trees
Effect to the Water cycle:
When significant numbers of trees are cut down, it
disturbs the evaporation level and dries up the moisture
needed to continue the water cycle.
Effects to the Oxygen Cycle:
The cutting down of trees significantly reduces the rate of
this process, resulting in higher carbon dioxide in the
atmosphere and lower natural oxygen levels.
Effects to the Carbon Cycle:
When forests are cleared, carbon dioxide released in the
atmosphere increases resulting to a rise in global
temperature.
Effects to the Nitrogen Cycle:
Cutting down trees prevents animals from getting
nitrogen from the plants and thus decreases the flow of
the nitrogen cycle.

15. Effect to the Water cycle:
Dam construction would change water flow, water
temperature, water transparency, sediment regime and
nutriment.
Impoundments would increase potential for evaporation
which may lead to more rain and flooding.
Effects to the Oxygen Cycle:
Water released from dams may be warmer which can
only hold less oxygen.
Effects to the Carbon Cycle:
If water is stored in dams, there is a lack of oxygen and
the process will be slower. As a result, less carbon dioxide
is released.
Effects to the Nitrogen Cycle:
Dam construction can change the residence time of water
and thus affect degradation of nitrogen in reservoirs
which can impair our ability to breathe, limit visibility and
alter plant growth.
Cases: Kaliwa Dam Project

16. Cases: Villar converting Farmlands to homes
Effect to the Water cycle:
Developments would alter waterways and increase storm
runoff which would result to flooding, eroded stream
banks, and widen stream channels which may damage
properties.
Effects to the Oxygen Cycle:
Conversion of farmlands reduces the rate of this process,
resulting in higher carbon dioxide in the atmosphere and
lower natural oxygen levels.
Effects to the Carbon Cycle:
Conversion of land causes a large reduction of carbon
storage in vegetation and soil.
Effects to the Nitrogen Cycle:
Land conversion or development would reduce nitrogen
retention and increase nitrogen export. Excess nitrogen in
the atmosphere can produce pollutants such as ammonia
and ozone, which can impair our ability to breathe, limit
visibility and alter plant growth.

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