method of estimating marine primary productivity

1. Method of
estimation of
marine primary
productivity
Presented by
ATHIRA P K
AEM 2018-20-02
Dept. of Aquatic Environment
Management, KUFOS

2. Introduction
○ Ecology involve the study of natural system ,
including the inter connection with the living and
non living parts
○ Ecosystem depends on the activity of plants
○ In ocean common plants are unicellular
phytoplankton
○ Photosynthesis is the critical link between the
living and non living world in the ecosystem
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3. PRIMARY PRODUCTIVITY ???
Is the rate at which energy is converted by photosynthetic &
chemosynthetic autotrophs to oganic substances.
○ About 55% of photosynthesis and production of biomass takes place in
marine systems and over 90% earth’s CO2 is recycled and stored through
marine systems
○ Measured- using bottled incubations, radioactive carbon, satellite borne
ocean color sensors
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4. Some
terminologies
PRIMARY
PRODUCTION
Is the synthesis of organic
compound from
atmospheric or aquatic
CO2
Chemosynthesis
&photosynthesis
GROSS PRIMARY
PRODUCTIVITY
Rate at which the
photosynthesis or
chemosynthesis occur.
NET PRIMARY
PRODUCTIVITY
NPP= GPP-RESPIRATION.
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Unit of GPP&NPP
g C/ unit area/unit year

5. 5
Photosynthesis
solar radiation  chemical energy and
STORED in the molecule of food
or
inorganic molecule  organic molecule in the presents of
sun light
Autotrophs
6CO₂+ 6H₂O+ Solar Energy  C₆H₁₂O₆ +6O₂
Heterotrophs
C₆H₁₂O₆ +6O₂ 6CO₂+6H₂O+ Energy
Food chain & food web
Trophic level

6. Producers in
sea...........
○ Phytoplankton include diatoms, dinoflagellates,
coccolithophores, sillicoflagellates and blue green
algae
○ Benthic producers in sand and mud bottoms -
mixtures of algae and vascular plants growing in
or anchored to sand and mud bottom in shallow
water
○ In Salt marshes- primary producers vascular plants
○ In rocky bottoms- macro algae
○ In shallow depths in tropical regions – coral reefs-
zooxanthellae
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8. Factors
affecting
primary
production.........
Primary factors
○ Solar radiation
○ Nutrient
concentration
Secondary factors
○ Upwelling turbulence
○ Grazing intensity
○ Water turbidity
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9. Technique
 GPP is always harder to measure than NPP. Because product of primary production is
used for respiration before they can be accurately measured.
 In shallow aquatic system a substantial proportion of total productivity is shunted to
below ground organ and tissue, where it is logistically difficult to measure.
In aquatic ecosystem primary production typically
measured by
1. Variation of O2 concentration with in sealed bottle(
Gaarder& Gran 1927)
2. Incorporation of inorganic C14 into organic matter
3. Fluorescence kinetics
4. Oxygen /Argon ratio
5. Remote sensing
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10. 1.
VARIATION IN
OXYGEN
CONCENTRATION
10Three identical transparent vessels are filled with sample water
.
The first one is analyzed immediately and used to determine the
initial oxygen concentration; usually this is done by
performing a Winkler titration.
The other two vessels are incubated, one each in under light and
darkened.
After a fixed period of time, the oxygen concentration in both
vessels is measured.
dark vessel provides a measure of ecosystem respiration
The light vessel permits both photosynthesis and respiration, so
provides a measure of net photosynthesis

11. Introduced by Danish scientist- Einer Steeman Neilsen
Labeled Na₂CO3 is commonly used for this technique
As 14C is radioactive ( beta decay), its decay is directly measured by
scintillation counters. Scintillation_Detector.gif
GPP is best estimated within short time period, since the loss of
incorporated 14C by respiration and organic material excretion /
exudation.
Loss processes can range between 10-60% of incorporated 14C
according to the
-incubation period
-ambient environmental conditions (especially temperature)
- the experimental species used.
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Incorporation
of inorganic 14C
into organic
matter
.
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12. 12
PROCEURE
A known quantity of 14C in the form of Na2CO3 is added to seawater
samples contained in transparent and opaque bottle
Incubated for 0.5 hr to 24hr samples are filtered cells are killed 
quantify 14C
CALCULATION
Carbon uptake = (14C incorporated into organic form/ total14C added) x
available inorganic carbon x 1.05
The available inorganic carbon has to be measure by chemical means and the
value of 1.05 is a factor to account for the fact that 14CO2 is taken up at
somewhat slower rate than the lighter 12CO2

13. 3
stable isotopes
and O2/Ar
ratios
○ The methods based on have the advantage of
providing estimates of respiration rates in the light
without the need of incubations in the dark.
○ O2/Ar have the additional advantage of not needing
incubations in closed containers
○ O2/Ar can even be measured continuously at sea
using equilibrator inlet mass spectrometry (EIMS) or a
membrane inlet mass spectrometry (MIMS)
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14. 4.
FLOURESCENCE
MEASUREMENTS
 Fluorescence sensors- used to determine insitu
concentrations of chlorophyll and therefore
phytoplankton biomass. Can be deployed for long
term-seasonal dynamics of phytoplankton
biomass can be elucidated in fine detail
 Chlorophyll fluorescence is light re-emitted by
chlorophyll molecule during excited to non-
excited state.
 Pulse amplitude modulated (PAM) flourometry is
becoming widespread tool for measuring in situ
photosynthesis.
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15. 5.
REMOTE
SENSING
○ Satellite and aircraft borne colour sensors can record the
color of water masses and using sophisticated algorithms,
can allocate the colour to concentration of dissolved
constituents, such as colored dissolved organic matter
(CDOM), suspended solids and chlorophyll and other
algal pigment concentration.
○ Only means we have for looking at large scale
distributions of phytoplankton
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16. 16
Light detection and ranging (LIDAR) flights use a variety of pulsed lasers
to stimulate phytoplankton chlorophyll and other pigments to fluoresce
and the fluorescent signals are then detected by sensors on the aircraft
Can be collected rapidly and relayed easily
Major disadvantage of ocean color sensors is that only the color of the
very top few meters of the oceans that is measured. Subsurface
chlorophyll maxima and accumulations of chlorophyll associated with
sub surface processes are not accounted for using these sensors

17. 17
Oceansat-2 is an Indian satellite designed to study surface winds and
ocean surface strata, observation of chlorophyll concentrations,
monitoring of phytoplankton blooms, and suspended sediments in the
water.

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21. Thanks….
Any questions?
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22. Credits
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