biogeochemical cycles

1. BIOGEOCHEMICAL
CYCLES
MADE BY- RASHMI KUMARI
MSc Bioscience ( previous)

2. What Sustains Life on Earth?
 Solar energy,
the cycling of
matter, and
gravity sustain
the earth’s life.

3. MATTER CYCLING IN
ECOSYSTEMS
Nutrient Cycles: Global Recycling
Global Cycles recycle nutrients through the
earth’s air, land, water, and living organisms.
Nutrients are the elements and compounds
that organisms need to live, grow, and
reproduce.
Biogeochemical cycles move these
substances through air, water, soil, rock and
living organisms.

4. ‘Fundamentals’ of
biogeochemical cycles
All matter cycles...it is neither created
nor destroyed...
As the Earth is essentially a closed
system with respect to matter, we can
say that all matter on Earth cycles .
Biogeochemical cycles: the movement
(or cycling) of matter through a system
by matter we mean: elements (carbon,
nitrogen, oxygen) or molecules (water)

5. TYPES OF BIOGEOCHEMICAL
CYCLES
♦ Water cycle
♦ Oxygen cycle
♦ Carbon cycle
♦ Nitrogen cycle
♦ Phosphorous cycle
♦ Sulphur cycle.

6. HYDROLOGICAL CYCLE (WATER
CYCLE)
• Defined: Movement of water through the
atmosphere
• 75% of the earth is water
• 99% of water undrinkable (salty & frozen)
• Water recycles over and over
 Makes up 60-70% of your body

7.  Water rises into the atmosphere in two ways:
◦ Evaporation: Heat changes water from a
liquid to a gas
◦ Transpiration: Water evaporates from the
leaves of plants through openings called
stomata

8.  Warm, moist air rises and eventually cools
◦ Condensation: process where water vapor
turns into a liquid
 Rain, snow, sleet, or hail falls when water drops
become heavy (Precipitation)

10. 1. Reservoir – oceans, air (as water
vapor), groundwater, lakes and
glaciers; evaporation, wind and
precipitation (rain) move water
from oceans to land
2. Assimilation – plants absorb water from
the ground, animals drink water
or eat other organisms which
are composed mostly of water
3. Release – plants transpire, animals
breathe and expel liquid wastes

11. OXYGEN CYCLE
 Autotrophs: Release O2 into
atmosphere via photosynthesis
 All life: Absorbs O2 to be used during
cellular respiration
◦ Respiration: creates ATP energy for cells

13. CARBON CYCLE
• Carbon = (organic molecules)
carbohydrates, proteins, lipids, nucleic
acids
• Plants & autotrophs:
– Intake: Absorb CO2 from atmosphere
Create glucose & sugar via photosynthesis
– Output: Release CO2 during respiration
 Consumers
◦ Intake: Carbon moves up the food chain as 1
feeds on another
◦ Output: Release CO2 during respiration

14. • Decomposers
–Input: Feed on dead organic matter
–Output: Release CO2 during respiration
–Output: Organic molecules returned to soil
during decomposition
 Human Industry
◦ Output: Release CO2 into atmosphere when
fossil fuels (coal, oil, natural gas) are burned

16. carbon is required for building organic
compounds
1. Reservoir – atmosphere (as CO2), fossil
fuels (oil, coal), durable organic
materials (for example: cellulose).
2. Assimilation – plants use CO2 in
photosynthesis; animals consume
plants.
3. Release – plants and animals release CO2
through respiration and
decomposition; CO2 is released as
wood and fossil fuels are burned.

17. NITROGEN CYCLE: KEY
POINTS
Nitrogen is in the atmosphere as N2
(78%)
N2 is an inert gas and cannot be used by
plants or animals.
N2 can be converted to a usable form via
◦ Lightening
◦ N-fixing plants and cyanobacteria
◦ Industrial process (energy intensive)
Nitrogen limits plant growth.
Nitrogen is easily lost from biological
systems.

19. 1. Reservoir – atmosphere (as N2); soil (as
ammonium, ammonia, nitrite, nitrate
2. Assimilation – plants absorb nitrogen as
either NH4
+ or as N03
-, animals obtain
nitrogen by eating plants and other
animals.
3. Release – Denitrifying bacteria convert
N03
- back to N2; detrivorous bacteria
convert organic compounds back to NH4
+ ;
animals excrete NH4
+, urea, or uric acid.

20. PHOSPHOROUS CYCLE
Slide 41Slide 41Slide 41
GUANO
FERTILIZER
ROCKS
LAND
FOOD
WEBS
DISSOLVED
IN OCEAN
WATER
MARINE
FOOD
WEBS
MARINE SEDIMENTS
weathering
agriculture
uptake by
autotrophs
death,
decomposition
sedimentation settling out weathering
leaching, runoff DISSOLVED IN
SOIL WATER,
LAKES, RIVERS
uptake by
autotrophs
death,
decomposition
miningmining
excretionexcretion
Figure 4-33
Page 82
uplifting over
geologic time

21. Phosphorus is required for the manufacture of
ATP and all nucleic acids
1. Reservoir – erosion transfers phosphorus to
water and soil; sediments and rocks
that accumulate on ocean floors return
to the surface as a result of uplifting by
geological processes
2. Assimilation – plants absorb inorganic PO4
3-
(phosphate) from soils; animals obtain
organic phosphorus when they eat
plants and other animals
3. Release – plants and animals release
phosphorus when they decompose;
animals excrete phosphorus in their
waste products

22. IMPORTANCE OF
PHOSPHOROUS CYCLE
1.Phosphorous is an essential nutrient of both
plants and animals.
2. It is part of DNA molecules which carry
genetic information.
3. It is part of ATP and ADP that store chemical
energy for use by organisms in cellular
respiration.
4. Forms phospholipids in cell membranes of
plants and animal cells.
5. Forms bones, teeth, and shells of animals as
calcium phosphate compounds.

23. SULFUR CYCLE
Slide 42Slide 42Slide 42
Figure 4-34
Page 83
Sulfur
Hydrogen
sulfide
Sulfate salts
Plants
Acidic fog and
precipitation
Ammonium
sulfate
Animals
Decaying
matterMetallic
sulfide
deposits
Ocean
Dimethyl
sulfide
Sulfur dioxide Hydrogen
sulfide
Sulfur trioxide Sulfuric acid
Water
Ammonia
Oxygen
Volcano
Industries

24. IMPORTANCE OF SULFUR
CYCLE
1.Sulfur is a component of most proteins and
some vitamins.
2.Sulfate ions (SO4
2- ) dissolved in water are
common in plant tissue. They are part of
sulfur-containing amino acids that are the
building blocks for proteins.
3.Sulfur bonds give the three dimensional
structure of amino acids.
4.Many animals, including humans, depend on
plants for sulfur-containing amino acids.