Productivity in ecosystem

you will learn about the primary and secondary productivity involved in ecosystem and about its types. it includes gross and net primary productivity also.

2. PRODUCTIVITY
●The productivity of an ecosystem refers to the rate of production, i.e., the
amount of organic matter accumulated in any unit time.
●Ecosystem productivity represents the total amount of energy (the
organic matter) fixed or stored by the autotrophs per unit time in
ecosystem .
●Measured as such as grams per square metre per day (g m
−2
d
−1
)
●It is of two types:
1.PRIMARY PRODUCTIVITY
2.SECONDARY PRODUCTIVITY

3. PRIMARY PRODUCTIVITY
➔It is the rate at which the the solar energy
is stored or trapped by the autotrophs,
➔In other words the amount of biomass or
organic food produced by autotrophs per
unit are during the process of
photosynthesis.
➔These plants can make food because they
are photosynthetic due to presence of the
green pigment chlorophyll.
➔These are further of two types:
1.GROSS PRIMARY PRODUCTIVITY
2.NET PRIMARY PRODUCTIVITY

4. GROSS PRIMARY PRODUCTIVITY
❖GROSS means TOTAL PHOTOSYNTHESIS
❖It represents the total organic matter
synthesised by the producers by
photosynthesis unit area and time.
❖It includes the organic matter or basically
energy used up during process of respiration,
metabolism etc.
❖It depends on the chlo rophyll content
❖estimated in terms of either chlorophyll
content as chl/g dry weight/unit area,
or photosynthetic number, i.e., amount
of CO2 fixed/g chl/hour.

5. NET PRIMARY PRODUCTIVITY
●Also known as NET ASSIMILATION
●It is defined as the amount of
energy or organic matter stored or
fixed at the first trophic level after
respiration that is available to the
higher trophic levels.
●NPP = GPP - RESPIRATION (OR
CELLULAR WORK)

7. RELATION OF SOLAR RADIATION AND
PRIMARY PRODUCTIVITY

8. SECONDARY PRODUCTIVITY
➢This represents the energy storage at the
consumer level.
➢The energy resulting from the primary
production furnishes the energy provided
to the rest of the higher trophic levels.
➢Some of the energy in the form of food is
consumed by herbivores or carnivore
which are other eaten by the omnivore .
➢Much of the ingested food is not
assimilated , only 10% of the food is
ingested and absorbed rest of it is excreted
out from the body.