1. There are two main methods to measure primary productivity in aquatic ecosystems - classical methods and modern methods. 2. Classical methods include the harvest method, bomb calorimeter method, chlorophyll method, and light-dark bottle (dissolved oxygen) method. The light-dark bottle method is the most common for measuring net primary productivity in both marine and freshwater systems. 3. The light-dark bottle method uses paired light and dark bottles to measure photosynthesis, respiration, and net primary productivity of phytoplankton over a period of time by tracking changes in dissolved oxygen levels between the bottles.

1. * MEASUREMENT OF PRIMARY
PRODUCTIVITY:- AQUATIC
ECOSYSTEM
Presented to: Presented by:
Dr. S.SUNDARAMOORTHY Narpat Singh
Prof. Msc. 3rd sem

2. *Measurement of primary
productivity in aquatic system
measurement are two types:-
1. Classical method :-
i. Aquatic system :- four method
 Harvest method
 Bomb calorimeter
 Chlorophyll method
 Dissolve oxygen method/O2 assimilation D.O./Light-Dark
bottle method
2. Mordan method

3. *1.Harvest method
 harvest method harvest in quantified in terms of biomass,
economic, biochemical, biomass can be fresh weight (aquatic
system).
When we apply in aquatic system (maprophyte +
phytoplankton present)macrophyte harvesting in unit area by
uprooting phytoplankton are filter taking unit volume or
filtration is taking.
The sample can be economic yield part is referred to as
production measurement.
In case of chlorophcea protest bacteria measurement or
protein per unit volume.

4. *Bomb -calorimeter
The bomb calorimeter consist primarily or the sample. Energy
turn of 1g biomass is dryad
Bomb calorimeter in steel jacket burn or sample generating heat
and have water, temperature in increased and read on Bachmann
thermometer
1* c temperature increased / rise similar to 1 kcal energy.

5. *Continue…
*Merit :-
 it required minimum equipment/tool.
It is actual and easy to perform.
Applicable for all ecosystem.
Demerit:-
It is destructive method.
It measure only in NPP& NCPP.
After harvesting respiration loss.

6. *2.Chlorophyll- method
It is used commonly in aquatic system specially
phytoplankton more chlorophyll.
This is a classical method.
In aquatic system (phytoplankton) chlorophyll content
quantify different interval and productivity predicated of
volume per unit area of volume.
Chlorophyll content α energy capture
Energy capture α productivity

7. *3.light-Dark bottle-method
Also called is dissolved oxygen method/ O2 assimilation D.O.
Classical method most common or measurement of NPP in both
marine and fresh water aquatic system.
6CO2 +12H2 O chlorophyll C6 H12 O6 +6O2 +6H2O.
 This process in aquatic system results in release of O2 in water
and this O2 dissolve in water and DO content increased equal
amount or CO2 absorption and equal amount of is release in
water.

8. *Continue…
Paired light and dark bottles are used to measure
photosynthesis(GPP) , respiration and NPP by phytoplankton
in aquatic system.
A sample of water containing phytoplankton (primary
producer) is placed in both bottles and allowed to incubates
for a period 6h of time.
DOlight – DODark = NPP
Respiration = Doinitial - Dodark
GPP= NPP+R

9. *Continue…
In the light bottle O2 is produced in photosynthesis and
consumed in respiration .
The resulting change (increase) in O2 concentration represents
the different in the net it which these two process occur:
1. NPP water is also incubated over time the same time .
2. another set of dark bottles the lack or light will prevent
photosynthesis.
The oxygen content of the water will decline as a function of
respiration . The different between the values of oxygen
(initial) and later dark is respiration.
The different between the values of O2 in the light
(photosynthsis+respiration) and dark (respiration) bottle at the
end or the time period therefore provides total photosynthesis
=GPP.