Presented by Dr Gurmeet Singh, Futuristic Research Division, National Centre for Sustainable Coastal Management Ministry of Environment Forest & Climate change at Mangrove Research in Indian sub-continent: Recent Advances, Knowledge Gaps and Future Perspectives on 8 - 10 December 2021

1. Dr GURMEET SINGH
Futuristic Research Division
National Centre for Sustainable Coastal Management
Ministry of Environment Forest & Climate change
gurmeet@ncscm.res.in

2. • Ph.D. in Environmental Sciences (2010),
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
• Scientist,
National Centre for Sustainable Coastal Management,
Ministry of Environment, Forests and Climate Change, Govt. of India
• Climate Change mitigation & Coastal Ecosystem,
• Blue carbon studies (seagrass and mangrove ecosystems)
• Nutrient budgeting in Indian estuaries
• Coastal Zone Management
• Waste management
https://www.ncscm.res.in

3. Source of Data
Research carried out by NCSCM in Indian coastal ecosystem,
unless specified other wise
Special volume : Seagrass Ecosystems of India
Eds. E. Vivekanandan, Ramesh Ramachandran, T. Thangaradjou
Volume 159,Pages 1-56 (1 June 2018)

4. Blue carbon research: An Indian Perspective
• Climate Change and Coastal Ecosystems
• Mangroves of India
• Emissions and Uptake
• Carbon burial
• Seagrass of India
• Overview
• Emissions and Uptake
• Carbon burial
• Key messages

5. Climate Change and Coastal Ecosystems
• Global average atmospheric CO2
concentration
• >400 parts per million
• Highest in past 800,000 years
• Global climate Change
• Rise in atmospheric temperature
• Global mean sea level rise

6. Climate Change and Coastal Ecosystems
• Mitigation approaches include
• Conservation of natural ecosystems
with high C sequestration rates and
capacity
• Blue Carbon Ecosystems (mangroves
and seagrass)
• Play a vital role in the global carbon
sequestration
• Long term storage as biomass
produced and buried in sediments
Oceans can sequester more than one third of the anthropogenic carbon

7. Carbon burial rates (Mg C ha-1 y-1) of different (terrestrial and Coastal & marine) vegetative
ecosystems (redrawn from Mcleod et al., 2011)

8. Blue Carbon Ecosystems
• Role of blue carbon ecosystems in mitigating climate change
▪ Contribution to long-term C sequestration >>terrestrial forests
▪ Seagrass  500 t CO2e/ha,
▪ Estuarine mangroves  1,060 t CO2e/ha and
▪ Oceanic mangroves 1,800 t CO2e/ha
Seagrass meadows occupy < 0.2% of the area of the world’s oceans,
Contribute  10% of the yearly Corg burial in the oceans

9. Blue Carbon Ecosystems: Need for Conservation
• During past decades-
• Cumulative losses of coastal vegetation ~ 25–50% of total global area
• Estimated Annual Loss varying from 0.5% to 3% (Pendleton et al, 2012).
• Causes of habitat conversion varies around the world -
• Transformation of mangrove areas to aquaculture and agriculture,
• Exploitation of forest resources,
• Conversion of mangrove ecosystems for industrial and urban development
• Action is urgently required to prevent further degradation and loss of such key
ecosystems.
• Recognizing the C sequestration value these ecosystems provide, there is a strong
need for their protection and restoration

10. Blue Carbon:
Offsetting carbon emissions by
conserving coastal vegetative ecosystem
www.anl.com.au
Rationalization of data set
Diverse methodology
Difficult to compare

11. Mangrove ecosystems of India

12. Mangrove species diversity and distribution in India
State/UT Mangrove Diversity
East Coast of India
Sundarban 33 true mangrove species; 21 genera and 14 families
Bhitarkanika 35 true mangrove species; 20 genera and 14 families
Coringa 22 true mangrove species; 15 genera and 11 families
Kaveri delta 17 true mangrove species; 12 genera and 8 families
Puducherry 15 true mangrove species; 10 genera and 7 families
West Coast of India
Gujarat 15 species; 10 genera and 6 families
Daman and Diu 4 species; 4 genera and 4 families
Maharashtra 22 species; 15 genera and 11 families
Goa 16 true mangrove species; 11 genera and 7 families
Karnataka 16 species; 11 genera and 7 families
Kerala 19 mangrove species; 12 genera and 8 families
Islands of India
Andaman and Nicobar 38 mangrove species 13 families and 19 genera
Lakshadweep 8 species belonging to 5 genera and 3 families

13. GHG emissions from mangroves
State-wise % contribution of CO2 fluxes from mangrove ecosystems
(Flux values are represented as Gg CO2e y-1)

14. GHG emissions from mangroves
State-wise % contribution of CH4 fluxes from mangrove ecosystems
(Flux values are represented as Gg CO2e y-1)

15. Carbon uptake by Mangrove ecosystems
• Net primary production (NPP) is the first visible step in carbon accumulation that is
quantified as the conversion of atmospheric CO2 into plant biomass
• Highly productive and diverse mangrove species with dense crown cover observed
Sundarban, Bhitarkanika, Coringa and Pichavaram along the east coast
• Net carbon uptake rate in mangrove of east coast varied between 3.26 Mg C ha-1
yr-1 to 35.44 Mg C ha-1 yr-1
• Net carbon uptake rate was highest in Heritiera fomes - Excoecaria agallocha -
Avicennia marina community in the eastern part of Sundarbans.
• In Pichavaram, average carbon uptake rate of Avicennia was 28.8 Mg C ha-1 yr-1.
• Compared to east coast, mangroves of west coast are patchy and less diverse and
composed mainly of single species zonation.
• Carbon uptake rates were comparatively lower (2.33 --26.98 Mg C ha-1 yr-1 ) in
mangroves of west coast

16. Carbon burial as mangrove biomass
• Overall annual accumulation rate of carbon as
live biomass in Sundarban is reported as 4.71–
6.54 Mg C ha−1 y−1 (Ray et al., 2011)
• In Bhitarkanika, Exocaria agallocha (tree density
3585/ha) and Hertiera fomes (tree density
2011/ha) with high basal area that dominated
the overall canopy (Mishra et al., 2005,
Upadhyay and Mishra, 2014).
• Highest carbon sequestration rates observed
from mangroves of south Gujarat (180.24 Mg ha-
1) followed by Saurashtra (83.42 Mg ha-1) and Gulf
of Kachchh (82.90 Mg ha-1) (Pandey and Pandey,
2013).
• Highest carbon stock per unit area is observed
from Andaman and Nicobar Islands

17. Carbon stock in Indian mangroves
Total
Sediment
Carbon
Stocks (Gg)
from Indian
Mangrove
Ecosystems
SOC ???

18. Carbon stock in Indian mangroves
Total
Sediment
Carbon
Stocks
(mg/ha)
from Indian
Mangrove
Ecosystems
SOC ???

19. Characterizing Carbon
• Variations mangrove biomass and
carbon density in 12 mangrove
species were quantified to
understand the potential of carbon
storage in the live mangrove
biomass
• Inter-species variations were
estimated in :
• mangrove stem biomass,
• ligno-cellulose content and
• elemental composition
— The lowest carbon density and highest ratio
of cellulose/lignin in the Sonneratia apetala
and Sonneratia caeseolaris species indicated
faster growth among all the studied species.
— Avicennia officinalis and Heritiera fomes were
identified with higher AGBs and carbon
storage potentials.
— Hertiera littoralis and Kandelia candel with
relatively higher lignin content with respect to
cellulose showed greater potentials to sustain
biotic and abiotic stresses, and higher
recalcitrant biomass.

20. Seagrasses
• Angiosperms (flowering plants) that live life entirely underwater
https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-seagrass-beds

22. Habitat and Nursery ground Food for Dugongs, Turtle & Swans
Factors Affecting Seagrass Distribution
•Temperature
•Salinity
•Waves
•Currents
•Depth
•Subsratum
•Day length
• Light
• Nutrients
• Epiphytes
• Disease

23. Seagrass plays an important role in
•Provide a natural sea defence by trapping sediment
•Provides a nursery ground for many commercial fish
•Carbon sequestration
•Produces the oxygen (oxygen pump)
•Promoters of biologica productivity and biodiversity
•Improve the water quality
•mportant elements of coastal protection
Seagrass Biodiversity

24. Low
DIC
fluxes
Increased
calcification
rates
DRY SEASON/HIGH SEAGRASS BIOMASS
Increase in pH
High
photosynthetic
uptake of DIC
HighO2
Pumping
Autotrophicseagrass with increased
DIC uptake and increased pH
Carbon burial
Bicarbonate
Dissolution
TA
Carbon burial
Increased
DIC
fluxes
Reduced
calcification
rates
WET SEASON/ LOW SEAGRASS BIOMASS
No significant change in pH
Reduced
photosynthetic
uptake of DIC
Less O2 Pumping
Hetrotrophic seagrass with reduced
DIC uptake
TA
Carbon sequestration in Seagrass Ecosystem

25. Distribution of Major Seagrass Ecosystems in India
Ecosystem
Area *
(sq. km)
Palk Bay 175.20
Gulf of Mannar 85.50
Chilika lagoon 85.00
Lakshadweep 2.20
A&N Islands 8.30
Gulf of Kachchh 6.26
Total 357.46

26. Seagrass Productivity and
Carbon storage

27. GHG Emission by seagrass ecosystem
Net Emission (Gg CO2 equivalent) from major Indian seagrass ecosystems
(Areal extent Palk Bay 330 km2 and Chilika 75 km2, ~80% of the total cover 517 km2)

28. GHG emissions : Mangroves vs seagrass
Comparison of Net Emission (Gg CO2 equivalent) from studied Indian Blue carbon
ecosystems (Total mangrove and seagrass cover 5,403 km2 and 517 km2, respectively)

29. -40
-30
-20
-10
0
10
20
30
40
50
60
Halophyla +
Halodule
Halodule sp. Non seagrass Halophyla +
Halodule
Halodule sp. Non seagrass
Dry Wet
mmol
C
/m2/day
Gross Productivity Respiration Net Productivity
Increased fresh water input results in the dominance of respiration processes in seagrass
Phytoplankton Productivity
Seagrass Productivity

30. 0
50
100
150
200
250
300
350
400
450
500
Cymodocea sp. Cymodocea &
Syringodium
Cymodocea sp. Cymodocea &
Syringodium
Dry Wet
mmol
C
/m2/day
Gross Productivity Respiration Net Productivity
Seagrass productivity is much higher than water column productivity
Productivity in Seagrass Ecosystem
Water column productivity Water column respiration
Primary Productivity

31. 0
50
100
150
200
250
300
350
400
450
500
Cymodocea sp. Cymodocea &
Syringodium
Cymodocea sp. Cymodocea &
Syringodium
Dry Wet
mmol
C
/m2/day
Gross Productivity Respiration Net Productivity
Water column productivity Water column respiration
Seagrass productivity is much higher than water column productivity
Chilika
Seagrass Productivity
Seagrass Productivity
Palk Bay

32. • Central Sector and Southern sector : Autotrophic during dry season .
• Outer channel : Heterotrophic throughout the year
• Higher rate of biological carbon sequestrations during dry season
-400
-350
-300
-250
-200
-150
-100
-50
0
50
Northern
Sector
Central Sector Outer Channer Southern
Sector
NEM
(P-R)
Dry Wet
-50
-40
-30
-20
-10
0
10
20
NEM
(P-R)
Dry Wet
-50
-40
-30
-20
-10
0
10
20
Northern Sector Central Sector Outer Channer Southern Sector
NEM
(P-R)
Dry Wet
Chilika
Role of seagrass in trophic state

33. Phytoplankton
NCP (phytoplankton) = 3-12 mmol C m-2d-1
Seagrass
NCPseagrass = 65-232 mmol Cm-2 d-1
Net Community Productivity of Seagrass > >Phytoplankton productivity
Potential Carbon Sinks

34. Shoot
:
Root
Ratio

35. • Efficient transport and storage of
sequestered carbon from the above
ground to below ground part
• Sediment carbon content is high in top
30 cm, suggesting active zone for carbon
storage
• Store the sequestered C for million of
years and act as a potential CO2 sink
0
10
20
30
40
50
60
70
80
90
0.00 1.00 2.00
Depth
in
cm
Sediment organic carbon (%)
Carbon Burial

36. Chilika
Carbon Budgets in Chilika Lagoon
Chilika
( Seagrass area : 85 km2)
Water column
DIC =0.013 Tg C
0.06 Tg C y-1
Burial
rates
2
m
1
m
Sediments
0.76 Tg C
Below Ground Biomass
0.008 Tg C
Above Ground Biomass
0.002 Tg C
0.08 Tg C y-1
Respiration

37. Carbon Budget in Palk Bay

38. INDIA

39. To Summarize

40. Wetlands and submerged aquatic vegetation including
marshes, mangroves, and seagrass contribute significantly to
the global stored carbon sink (IPCC, 2006)
Ecosystem
Global area
(Mha)
Global Carbon burial
(Tg C Yr-1)
Annual rate of
Global loss (%)
Seagrasses
Mangroves
Salt marshes
17.7 to 60
13.8 to 15.2
2.2 to 40.0
48 to 112
31.1 to 34.4
4.8 to 87.2
~7
~0.7 to 3
~1 to 2
Mcleod et al., 2011
A blue print for blue carbon

41. Comparison of sediment organic carbon stocks in major forest ecosystem
of India (Khurana, 2012 and NCSCM study).

42. Key Outcome
Mangrove Seagrass
Net C accrual per hectare per year 1.69 Mg 1.66 Mg
Additional CO2 sink by increasing 20% area cover per
year
~669 Gg ~84.4 Gg
Restoration of 100 ha of stressed/ degraded ecosystem
will reduce CO2 emissions per year by
144 Gg 52.2 Gg

44. Thank You