1. Prepared by: Nikki Rose D. Dapanas
BS Environmental Science III
Prof. Magdalyna Dulay

2. Chapter 7: Terrestrial
Decomposition
Types of Processes in
Decomposition
Leaching of Litter
Litter Fragmentation
Chemical Alteration

3. Chapter 7: Terrestrial
Decomposition
Temporal and Spatial
Heterogeneity
Decomposition
Temporal Pattern
Spatial Pattern

4. Chapter 7: Terrestrial
Decomposition
Factors Controlling
Decomposition
Physical Environment
Substrate Quality & Quantity
Microbial Community

5. Chapter 7: Terrestrial
Decomposition
Decomposition at the
Ecosystem Scale
Anaerobic Heterotrophic
Respiration

6. Decomposition breaks down
dead organic
matter, releasing carbon to
the atmosphere and nutrients
in forms that can be used for
plant and microbial
production.

7. This chapter describes
the key controls over
decomposition and soil
organic matter
accumulation by
ecosystems.

8. Conversion of
dead OM into
CO2 & inorganic
nutrients

9. Physical &
Chemical
breakdown of
detritus

10. Leaching
Fragmentation
Chemical
Alteration

11. Removes soluble
materials from
decomposing
organic material
by water
transfers.

12. Physical process
by w/c mineral
ions & small
water-soluble org.
cpd. Dissolved in
water & move
through the soils.

13. Soil animals
 Breaks large pieces of
organic matter into
smaller ones
 provide a food source
for soil animals
 create fresh surfaces for
microbial colonization

14. dead organic matter
is primarily a
consequence of the
activity of bacteria
and fungi
occur spontaneously
in the soil without
microbial mediation

15.  Fungi
 main initial
decomposers of
terrestrial dead
plant material
 80 to 90% of the
total decomposer
biomass &
respiration

16.  Bacteria
 small size & large
surface to volume ratio
of bacteria enable
them to absorb soluble
substrates rapidly & to
grow & divide quickly
in substrate-rich zones
 lysing & breaking down
live & dead bacterial &
fungal cells

17. Litter & animal
residues are
gradually
decomposed until
their original
identity is no
longer recognizable

18. Temporal pattern
 The predominant
controls over
decomposition
change with time.
 In seasonal
environments, micro
bial respiration often
occurs over a longer
time period.

19.  Spatial Pattern
 Most decomposition
occurs near the soil
surface, where litter
inputs are concentrated
 Decomposition rate is
spatially
heterogeneous at
several scales.

20. Physical
Environment
Temperature
Moisture
Soil Properties
Soil Disturbance

21.  affects
decomposition
 Directly promoting
microbial activity
 indirectly by altering
soil moisture and the
quantity & quality of
organic matter
inputs to the soil.

22. Carbon
accumulation is
greatest in wet
soils because
decomposition is
more restricted by
high soil moisture

23. Sufficient oxygen
is available
Decomposers
(plant) are most
productive under
warm moist
conditions.

24. decomposition
occurs more
rapidly in neutral
than in acidic soils
due to a variety of
interacting
factors.

25. increases
decomposition
by promoting
aeration
exposing new
surfaces to
microbial attack.

26.  Litter

27.  Soil Organic Matter

31. Decomposition
in anaerobic
environments
occurs slowly
and produces
energy
inefficiently.

32. God Speed 