Blue carbon is becoming widely recognised as a critical component of all national carbon accounting schemes. Australia has invested heavily in collating existing estimates of blue carbon stocks and is currently targeting important yet poorly represented habitats around its extensive coastline. Much of this effort is linked with the CSIRO-funded Coastal Carbon Cluster. This 3-year program has developed and validated many approaches to blue carbon estimation and is now able to showcase best-practice methods. The activities of the Cluster have been used as a model for international efforts to develop global estimates, as well as national blue carbon inventories via the International Blue Carbon Scientific Working Group. Finally, static estimates of carbon can only describe the current carbon stock at a specific location; models can extrapolate these relationships into unsampled regions, as well as estimate carbon stock into the future given changes to climate as well as alterations to the geochemistry/hydrodynamics of a specific habitat.

1. http://www.csiro.au/Coastal-Carbon-Cluster
Blue Carbon: Current status of
Australian estimates and future
model predictions
Peter Ralph, Carlos Duarte, Catherine Lovelock, Martina Doblin,
Stuart Phinn, Oscar Serrano, Trisha Atwood, Robert Canto, Virginie
van Dongen-Vogels, Joey Crosswell, Mark Baird and Andy Steven.

2. What is Blue Carbon?
• occupying only 2% of the seabed area, vegetated wetlands (seagrass, mangroves,
saltmarsh) represent 20% of the carbon transfer from oceans to sediments.

3. Blue Carbon Initiative
• Develop management approaches, financial incentives and policy
mechanisms for ensuring the conservation, restoration and sustainable
use of coastal blue carbon ecosystems;
• Develop comprehensive methods for assessing blue carbon stocks and
emissions;
• Support scientific research into the role of coastal blue carbon
ecosystems for climate change mitigation.

4. Marine and Coastal Carbon
Biogeochemistry Cluster
• 8 institutions (2013-2015)
> 50 scientists and students
~ 20 CSIRO scientists

5. Goals of the Cluster
– Improve our understanding of the spatial variability in carbon storage
to derive national estimates of ecosystem service
– Evaluate the impact of disturbances on Blue C storage when habitats
are modified
– Compile a national dataset on Blue C data (C stocks, flux, nutrient
stoichiometry and isotope C signatures).
– Develop quantitative models of carbon as required for Australian
coastal areas to improve global carbon estimates

6. Quantifying Coastal Carbon
Quantitative Modeling and
Economic Assessment

7. Sampling methodology

8. Mangrove Blue Carbon
Green  Achieved
Yellow Planned
Red  Region gap

9. Saltmarsh Blue Carbon
Green  Achieved
Yellow Planned
Red  Region gap

10. Seagrass Blue Carbon
Green  Achieved
Yellow Planned
Red  Region gap

11. Number of assessed sites
0
10
20
30
40
Mangroves
0
10
20
30
40
50
Salt marsh
0
50
100
150
Australia
Denmark
Spain
USA
United…
Other…
Italy
Philippi…
Greece
Malta
Thailand
Indone…
Mexico
Cyprus
Norway
Panama
France
Portugal
Seagrass

12. Data needed for repository
• illustrate with just seagrass habitat
– carbon stock with depth
– source (allochthonous v autochthonous)
– age of carbon
– recalcitrance of carbon
– carbon flux estimates
– potential for release after disturbance
• challenges of coastal ocean production estimates

13. M green 2 m
J grey 4 m
K orange 6 m
P blue 8 m
Q red control
0"
20"
40"
60"
80"
100"
120"
140"
0" 2000" 4000" 6000" 8000" 10000"
Cummula&ve)Biomass)
gOC)/m2)
Depth(cm) 0
20
40
60
80
100
120
140
C cummula ve biomass
kg OC m-2
0 2 4 6 8 10
4-fold difference in the
Corg stocks along a depth
gradient,
and up to 8-fold difference
between seagrass and un-
vegetated = C sinks
Carbon stores along a depth gradient
Serrano et al. 2014 GBC
deeper – less light

14. Processes controlling C stocks in
seagrass sediments
• productivity
• allochthanous inputs - wave energy
• depth – reduced light
Jimena Samper
What’s important?
Under revision – Limnology and Oceanography

15. Carbon stock and flux estimates
• cores provide stock estimates
• chambers provide flux estimates
http://www.labexmer.eu/
Pemika Apichanangkool

16. National data repository
• Parameter library
Barbara Robson - CSIRO

17. Benthic plant parameterisations
Coral biomass
Seagrass biomass
Benthic microalgae biomass
Spectrally-resolved optical model critical for
bottom growing conditions – now in near real
time

18. Increaseinspatialscale
Scaling of seagrass observations
Shoot
(mm-cm)
Shoots
(cm-m)
Patch
(m – 100m)
Patches
Meadow
(100m – km)
Regional Meadows
(km – 10km)
Ecosystem (10km-100km)

19. Australian coastal carbon estimation:
Global to continental to regional scale estimates from existing data
x
Carbon stock and
flux per unit area
Habitat
Area
= Carbon Stock
Global scale Continental scale Local scale
Seagrass
Saltmarsh
Mangrove
NT
VIC
TASQLD
SA WA
NSW
Single stock and flux value
per unit area
State specific stock and flux
value per unit area
Habitat type specific stock
and flux value per unit area

20. Data needed for repository
• illustrate with just seagrass habitat
– carbon stock with depth
– source (allochthonous v autochthonous)
– age of carbon
– recalcitrance of carbon
– carbon flux estimates
– potential for release after disturbance
• challenges of coastal ocean production estimates

21. V. van Dongen-Vogels108o
E 120o
E 132o
E 144o
E 156o
E
60o
S
45o
S
30o
S
15o
S
0o
SamplingYears
1990
2000
2010
45o
S
30o
S
15o
S
0o
onths
10
12
Coastal productivity
Sampling techniques
Sampling year
Sampling month

22. Parameter library
V. van Dongen-Vogels http://parameterlibrary.shinyapps.io/distributionexplorer

23. Summary
– spatial variability in carbon storage to derive national estimates of
ecosystem service
– national dataset on Blue Carbon data (C stocks, nutrient
stoichiometry and isotope C signatures).
– quantitative models of carbon are required for Australian coastal
areas to improve global carbon estimates

24. http://www.csiro.au/Coastal-Carbon-Cluster
Thank you for your attention
Peter.Ralph@uts.edu.au

25. CO2 emissions with degradation
Organic matter can be re-emitted as CO2 once the ecosystem is disturbed or degraded
Restoration can reinstate C sequestration
Few data to assess the risks of CO2 emissions
Developing a suite of tools for estimating potential for CO2 emissions

26. Estimate of seagrass area
• habitat area estimation

27. Blue Carbon policy
UNESCO/IUCN/IOC/CI recognised the gaps
– science: how much carbon can be lost/restored over time
– economics: at what cost?
– policy: can current policy frameworks work?
– 2012 - Verified Carbon Standard recognized Wetland Restoration and
Conservation for carbon finance.
– 2013 mangrove restoration was included in Reducing Emissions
Deforestation and forest Degradation (REDD+)
– 2013 - Intergovernmental Panel on Climate Change (IPCC) adopted the
Supplement to the 2006 Guidelines for National Greenhouse Gas Inventories:
Wetlands (Wetlands Supplement).

28. Model output

29. Australia’s coasts
• biodiverse
• highly productive
• significant store of carbon
• undergoing significant change
• un-quantified and unaccounted carbon

30. Coastal marine ecosystems
cover less than 0.5 % of total
marine surface …
Mangroves Salt marshes Seagrass
Ecosystem
Mangroves
Salt marsh
Seagrass
Area
(106 km2)
0.2
0.4
0.3-0.6
% marine
surface
0.05
0.1
0.07-0.15
Duarte et al 2005
mangrove salt marsh seagrass
Adapted from slides courtesy of C. Duarte

31. Benthic coupling
Environmental Controls
• Tidal amplitude
• Freshwater discharge
• Sediment load
• Temperature
• Eutrophication index
• Coastline/basin type
• Morphology
• Hydrology
• Lithology
Sediment Accretion data
Statistical Model
Spatially-explicit estimate of mangrove accretion rates

32. Mangrove and saltmarsh carbon stocks
UQ Graduate student
Matthew Hayes
• Variation in carbon over different
“settings”
• Most carbon is in riverine
settings
• In non-riverine settings carbon
increases with elevation above
What did we find?

33. LOSS OF CARBON STOCKS IN SEAGRASS MEADOWS
DUE TO MOORING ACTIVITIES
AT ROTTNEST ISLAND, WESTERN AUSTRALIA

34. LOSS OF CARBON STOCKS IN SEAGRASS MEADOWS
DUE TO MOORING ACTIVITIES

35. LOSS OF CARBON STOCKS IN SEAGRASS MEADOWS
DUE TO MOORING ACTIVITIES

36. LOSS OF CARBON STOCKS IN SEAGRASS MEADOWS
DUE TO MOORING ACTIVITIES
Loss of 4.8 kg Corg m-2 in the 50 cm-thick deposits studied as a result
of mooring deployments, and loss of 1.7 Kg Corg m-2 over an average
of 50 years after mooring deployment

37. 37
C stores along depth gradients in Posidonia meadows
94%
83%
46%
43%
20%
Depth SAR
2 m 1.3 mm y-1
4 m 1.5 mm y-1
6 m 0.8 mm y-1
8 m 1.0 mm y-1
Bare 1.5 mm y-1

38. Abstract – as submitted to Blue Planet
Symposium
• 15 min presentation only – just so you know what was submitted
• Blue carbon is becoming widely recognised as a critical component of all national
carbon accounting schemes. Australia has invested heavily in collating existing
estimates of blue carbon stocks and is currently targeting important yet poorly
represented habitats around its extensive coastline. Much of this effort is linked
with the CSIRO-funded Coastal Carbon Cluster. This 3-year program has developed
and validated many approaches to blue carbon estimation and is now able to
showcase best-practice methods. The activities of the Cluster have been used as a
model for international efforts to develop global estimates, as well as national blue
carbon inventories via the International Blue Carbon Scientific Working Group.
Finally, static estimates of carbon can only describe the current carbon stock at a
specific location; models can extrapolate these relationships into unsampled
regions, as well as estimate carbon stock into the future given changes to climate
as well as alterations to the geochemistry/hydrodynamics of a specific habitat.

39. V. van Dongen-Vogels
Phytoplankton production observations are not spatially and temporally consistent
in the methods used, years, and time of the year