Ecosystem

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SUBJECT:-ECOSYSYEM


ECOSYSTEM


WHAT IS AN ECOSYSTEM?

Bounded ecological system consisting of all the organisms in an area and the physical environment with which they interact

Biotic and abiotic processesPools and fluxes


Living aboveground phytomass

Living belowground phytomass

Mineral nutrients in soil solution

Uptake

ExudationWashout

Uptake for shoot production

Retranslocation

Humus

Humification

Immobilization

Standing dead

Litter

Mineralization

Decomposition

Animals

Excreta (Urine)

Degistation

Excreta (Dung)

Mineralization

Dead belowground phytomass

Decompo-sition

internal nutrient cycling

System input:

- wet and dry deposition- N2-fixation- fertilization- water inflow

SYSTEM DEFINITION NUTRIENT CYCLING

System output:

- water outflow- wind erosion - losses to air (denitrification)- fire (burning dung)- haymaking - animal products (meat, wool,...)


ECOSYSTEM STRUCTURE: TROPHIC RELATIONS

Trophic relationships determine an ecosystem’s routes of energy flow and chemical cyclingTrophic structure refers to the feeding relations among organisms in an ecosystemTrophic level refers to how organisms fit in based on their main source of nutrition, including


Trophic levels

• Primary producers: autotrophs (plants, algae, many bacteria, phytoplankton),

Primary consumers: heterotrophs that feed on autotrophs (herbivores, zooplankton);Secondary consumers heterotrophs that feed on primary consumers;Tertiary consumers (quatenary consumers);Detritivores (organisms that feed on decaying organic matter, bacteria, fungi, and soil fauna)Omnivores (feed on everything), frugivore, fungivore…….


OTHER DEFINITIONS

An ecosystem is a bounded ecological system that includes all the organisms and abiotic pools with which they interact.An ecosystems is the sum of all of the biological and nonbiological parts that interact to cause plants grow and decay, soil or sediments to form, and the chemistry of water to change.


Example 1• Small scale: e.g., soil core, appropriate for

studying microbial interactions with the soil environment, microbial nutrient transformations, trace gas fluxes,…

Example 2• Stand: an area of sufficient homogeneity with

regard to vegetation, soils, topography, microclimate, and past disturbance history to be treated as a single unit.

Appropriate for studying whole-ecosystem gas exchange, net primary productivity, plant-soil-microbial nutrient and carbon fluxes


[email protected] ITM STUDENT

Ecosystem

Engineering

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