scaling up carbon and carbonate production to regional scales with landsat 7 etm+ christopher s....

Scaling Up Carbon and Carbonate Production to

Regional Scales with Landsat 7 ETM+

Christopher S. Moses (USF)Serge Andréfouët (IRD)

Frank Muller-Karger (UMass)Christine Kranenburg (USF)

NOAA Think Tank #5: Ocean Acidification3-7 Dec. 2007, Little Cayman Research Center

C.S. Moses, Think Tank #5, Dec. 2007

Outline• Driving questions• Millennium Coral Reef Map• Location• Scaling up carbon and carbonate production• Conclusions• What’s next and what’s needed


Questions• Can remote sensing produce reasonably

accurate estimates of production over regional scales (103-104 km2)?

• Can the Millennium Map geomorphologic classes serve as proxies for production in areas with poor imagery or no data for validation?


Previous Scaling-up Work• Atkinson & Grigg (1984)

– French Frigate Shoals– Aerial photography– 3 classes

• Andréfouët & Payri (2001)– Moorea– SPOT (20 m resolution)– 9 classes

• Brock et al. (2006)– Biscayne National Park– ASTER (15 m), IKONOS (4 m), AISA (~1.5 m)– 4 classes

Andréfouët & Payri (2001)


Caribbean Region Scenes


Landsat 7 ETM+: Full Scene

~180 km

Path 14, Row 46

14 Feb. 2000


Millennium Map: Little Cayman


Measuring Production• Several methods

– Geochemical– Growth rate, density

• aka: census based

– Net accretion

• Geochemical measurements– Single points or arrays– Total alkalinity (TA), pH

– pCO2, HCO3-, or CO2

O2

Yates & Halley (2003)


Scaling-Up Production

• Assumptions:– In situ values are

representative over larger areas

– Production is linearly scalable

Ppatch reef = (Fsand x Psand) + (Fdense live x Pdense live )… + (Fi x Pi)


North Florida Reef Tract

Landsat 7 ETM+5 Feb 2000


In situ Production Values

P R E P/R G

Class (g C m-2 d-1) (g C m-2 d-1) (g C m-2 d-1) (g CaCO3 m-2 d-1)

Sand 1.76 1.96 -0.20 0.90 0.11

Seagrass 2.88 3.32 -0.44 0.87 -0.19

Sparse seagrass* 1.98 2.23 -0.25 0.89 0.05

Dense live substrate 6.43 8.09 -1.66 0.79 1.29

Sparse live substrate 4.23 5.31 -1.08 0.80 -0.04


NFRT Biotope Classification

Brock et al. (2006)


NFRT Spatial Production


Unit P, R, P/R, and G

Sensor P R E P/R G(g C m-2 d-1) (g C m-2 d-1) (g C m-2 d-1) (g CaCO3 m-2 d-1)

AISA 3.15 3.71 -0.57 0.85 0.04

IKONOS 3.52 4.20 -0.68 0.84 0.15

ASTER 4.05 4.91 -0.86 0.82 0.36

AISA corrected

3.11 3.67 -0.56 0.85 0.07

L7 NFRT total

3.03 3.61 -0.58 0.84 -0.002

Net heterotrophic

Net CO2 sink

Net Dissolution

Comparative Estimates

-1

0

1

2

3

4

5

P R E P/R G

g C m

-2 d

-1

IKONOS

AISA corrected

Landsat 7


Accuracy of L7• 86.2 (±2.3%) accuracy

over entire NFRT• Most TD >1.80• Lowest TD (0.63)

between shallow dense live and deep sparse live

• Sand is most easily misclassified


Proxy Stability

Millennium Coral Reef Map

P R E P/R G

Class (g C m-2 d-1) (g C m-2 d-1) (g C m-2 d-1) (g CaCO3 m-2 d-1)

Intra-seas patch reef complex (#568)

3.84 4.68 -0.84 0.84 0.30

Shelf terrace (#781)

3.46 4.19 -0.73 0.83 0.25

Cross shelf (#793) 2.90 3.43 -0.53 0.85 -0.07


Sensitivity AnalysisM

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Conclusions• Landsat 7 ETM+ imagery can produce

accurate biotope classifications and production estimates at regional scales

• Millennium Map classes can be used as proxies in areas with poor bathymetric control and little validation

• Limitations:– Dependent on accuracy of in situ observations– Greater numbers of classes decrease accuracy– MM classes only regionally applicable


Needs and Next Steps• Better spatial

coverage of in situ measurements of production– Keystone sites??

• Accurate measurements in deeper (>10 m) water depths– New technologies

• Integration into more complex models

Hochberg & Atkinson (2007)


Significance• Reefs fringe ~15% of world’s coastlines• High biodiversity

– >2,000 reef fishes– >800 species of corals

• Roberts, et al., 2002

• ~58% are threatened by human activities• Ginsburg, et al., 1994

• ~30% decline in calcification at 560 atm CO2 – Ωarag ~ 2.29

• Kleypas, et al. (2006)

• Need for ecosystem-based management approaches• Loreau, et al. (2003)


Previous Reef Maps

Solomon Islands


Millennium Coral Reef Map

Solomon Islands


Millennium Global Coral Reef Map

http://imars.usf.edu/corals/maps/reef_count.html


32 Geomorphic classes30-meter resolution

Millennium Map: Palau


NFRT Calcification (G)


Unit P, R, P/R, and G

Sensor P R E P/R G(g C m-2 d-1) (g C m-2 d-1) (g C m-2 d-1) (g CaCO3 m-2 d-1)

AISA 3.15 3.71 -0.57 0.85 0.04

IKONOS 3.52 4.20 -0.68 0.84 0.15

ASTER 4.05 4.91 -0.86 0.82 0.36

AISA corrected

3.11 3.67 -0.56 0.85 0.07

L7 NFRT total

3.03 3.61 -0.58 0.84 -0.002

Net heterotrophic: -5.74 x 108 kg C yr-1

Net CO2 sink: ~753 tons yr-1

Net Dissolution: 1.68 x 106 kg CaCO3 yr-1

Comparative Estimates

-1

0

1

2

3

4

5

P R E P/R G

g C m

-2 d

-1

IKONOS

AISA corrected

Landsat 7

scaling up carbon and carbonate production to regional scales with landsat 7 etm+ christopher s....

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