Date post: | 16-May-2015 |
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Prepared by: Nikki Rose D. DapanasBS Environmental Science III
Prof. Magdalyna Dulay
Terrestrial Decompositio
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Chapter 7: Terrestrial DecompositionTypes of Processes in DecompositionLeaching of LitterLitter FragmentationChemical Alteration
Course Outline:
Chapter 7: Terrestrial DecompositionTemporal and Spatial Heterogeneity Decomposition
Temporal PatternSpatial Pattern
Course Outline:
Chapter 7: Terrestrial DecompositionFactors Controlling Decomposition
Physical EnvironmentSubstrate Quality & Quantity
Microbial Community
Course Outline:
Chapter 7: Terrestrial Decomposition
Decomposition at the Ecosystem ScaleAnaerobic Heterotrophic Respiration
Course Outline:
Decomposition breaks down dead organic matter, releasing carbon to the atmosphere and nutrients in forms that can be used for plant and microbial production.
Overiew:
This chapter describes the key controls over decomposition and soil organic matter accumulation by ecosystems.
Overiew:
Conversion of dead OM into CO2 & inorganic nutrients
Decomposition…
Physical & Chemical breakdown of detritus
Decomposition…
LeachingFragmentation
Chemical Alteration
Types Of Processes
Removes soluble materials from decomposing organic material by water transfers.
Leaching…
Physical process by w/c mineral ions & small water-soluble org. cpd. Dissolved in water & move through the soils.
Leaching…
Soil animalsBreaks large pieces of organic matter into smaller ones
provide a food source for soil animals
create fresh surfaces for microbial colonization
Fragmentation…
dead organic matter is primarily a consequence of the activity of bacteria and fungi
occur spontaneously in the soil without microbial mediation
Chemical Alteration…
Fungimain initial decomposers of terrestrial dead plant material
80 to 90% of the total decomposer biomass & respiration
Chemical Alteration…
Bacteriasmall 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
Chemical Alteration…
Litter & animal residues are gradually decomposed until their original identity is no longer recognizable
Soil Organic Matter…
Temporal patternThe predominant controls over decomposition change with time.
In seasonal environments, microbial respiration often occurs over a longer time period.
Temporal and Spatial…
Spatial PatternMost decomposition occurs near the soil surface, where litter inputs are concentrated
Decomposition rate is spatially heterogeneous at several scales.
Temporal and Spatial…
Physical EnvironmentTemperature MoistureSoil Properties
Soil Disturbance
Factors Controlling Decomposition…
affects decompositionDirectly promoting microbial activity
indirectly by altering soil moisture and the quantity & quality of organic matter inputs to the soil.
Temperature…
Carbon accumulation is greatest in wet soils because decomposition is more restricted by high soil moisture
Moisture…
Sufficient oxygen is available
Decomposers (plant) are most productive under warm moist conditions.
Moisture…
decomposition occurs more rapidly in neutral than in acidic soils due to a variety of interacting factors.
Soil Properties…
increases decomposition by promoting aeration
exposing new surfaces to microbial attack.
Soil Disturbance…
Litter
Substrate Quality and Quantity…
Soil Organic Matter
Substrate Quality and Quantity…
Microbial Community…
HUMUS..
Decomposition at the Ecosystem Scale…
Decomposition in anaerobic environments occurs slowly and produces energy inefficiently.
Anaerobic Heterotrophic Respiration…
God Speed
Thank You For Listening…