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The carbon budget for coastal waters of the eastern United States

R. Najjar, M. Friedrichs, W.-J. Cai, D. Butman,K. Kroeger, W. M. Kemp,

M. Herrmann, L. McCallister, Z. Wang, S. Signorini, C. Pilskaln,

D. Burdige, P. Vlahos, R. Vaillancourt

Outline1. Importance

of coastal ocean

2. NACP Coastal Synthesis

3. East coast carbon budget

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Importance of the coastal ocean (depth < 200 m, 4.7% of ocean area)

Pg C yr-1 % ocean total

Primary Production

6.5 12

Export Production

2.0 21

Burial 0.67 86

Source: Dunne et al. (2007)

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NACP-OCB Coastal Synthesis ActivityObjective: “Stimulate the synthesis and publication of recent observational and modeling results on carbon cycle fluxes and processes along the North American continental margin”

• Phase 1: Regional carbon budgets• Phase 2: Community modeling & database development

• NASA & NSF support for regional workshops and post-doc• One workshop held (2012 East coast), one scheduled (Gulf

of Mexico, March 27-28, 2013 in St. Petersburg, FL)• Get involved! NACP web site Synthesis Activities

4Nationalatlas.gov

(Mathis)

Great Lakes(McKinley)

(Cai, Freidrichs, Najjar)

(Alin, Hales)

(Coble, Lohrenz)

Tidal wetlands Estuaries Continental shelfNPP Degassing

Burial

River input

BPP

Air-water exchange

POC export

The carbon cycle of the coastal ocean

POCDOC

DIC

Respiration (R)

Resuspension

NPP, RNPP, R

POCDOC

DIC

Sediments

Advective exchange

Open Ocean

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Coastal zone of the eastern

U.S.:Head-of-tide to

shelf break (~200 m)

% Area

Tidal wetlands

3

Estuaries 14Shelf waters

83

Gulf of Maine (GoM)

Georges Bank + Nantucket Shoals (GB + NS)

Mid-Atlantic Bight (MAB)

South Atlantic Bight (SAB)

See workshop report on

NACP web site (Najjar et al.

2012)

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River inputUSGS statistical models

TOCTg C yr-1

DICTg C yr-1

GoM 0.57 0.30MAB 1.45 1.63SAB 1.86 0.56East Coast 3.9 2.5

Also using process-based model (DLEM—see Tian et al. poster)

SPARROW (Shih et al. 2010)

LOADEST (Stets and Striegl 2012)

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Tidal wetlands

Delaware Bay

New Jersey

Delaware

Estuarine and marine wetlands

Current approach:• NWI• Break up wetlands by

subregion and salinity• Literature survey of

burial & lateral export• Average• Two estimates of NPP

www.smithtrail.net

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Tidal wetlands budget (Tg C yr-1)NPP

13-24Degassing

3-19

Burial1-2

2 DIC2-6 DOC? POC

Respiration (R) = 5-21

Lateral export

NPP – R = TOC export + Burial

R – NPP = DIC export + Degassing

Net uptake5-10

Empirical model (Childers et al. 2002) being adopted/refined

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Estuarine processes

• See Herrmann et al. poster

• Net ecosystem production (NEP = NPP – R) function of riverine DIN:TOC loading ratio

• Burial function of estuarine residence time

64 estuaries

Based on NOAA’s National Estuarine Eutrophication Assessment survey (Bricker et al. 2007)

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IntegrateEast coast estuarine NEP = -1.9 Tg C yr-1

Estuarine organic C budget (Tg C yr-1)

3.40.6

0.9

-1.9 NEP

Canada not included yet!

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Gulf of Maine (GoM)

Georges Bank + Nantucket Shoals (GB + NS)

Mid-Atlantic Bight (MAB)

South Atlantic Bight (SAB)

• Currently a literature synthesis

• Also using satellite algorithms and numerical models

• Respiration poorly constrained

120 ± 30 Tg C yr-1 primary production on continental shelf

47 ± 20

34 ± 10

35 ± 10

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Continental shelf air-sea exchange (Signorini et al. poster)

Surface pCO2 algorithm exploiting satellite data

Observed pCO2

Algo

rithm

pCO

2

UptakeTg C yr-1

GoM -0.1GB+NS 1.3MAB 2.1SAB 1.0East Coast 4.3

Flux = f(DpCO2, wind, SST)

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Continental shelf sedimentsDIC flux from sediments• DIC flux: estimated

from water depth • Similar approach

taken with DOC flux• Particle flux,

resuspension, burial data synthesized

• See Pilskaln et al. poster

Surface water POC export

Resuspension flux

Benthic DIC + DOC flux POC burial

>8 12 14 1

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Cross-shelf transport• Tracer-based approach: Vlahos et al. poster• MAB a DOC source and DIC sink (net autotrophic)

Numerical modeling approach: Friedrichs et al. poster

• Gives similar OC results but IC budget not in balance

Tidal wetlands Estuaries Continental shelf

NPP13-24

Degassing3-19

Burial1-2

River input3.9 TOC2.5 DIC

BPP

Air-water exchange

POC export >8

Overall US east coast budget

POC1 DOC+DIC

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Respiration (R)5-21

Resuspension12

-1.9 NEP

120 NPP, ? R

Burial0.9

Sediments

Advective exchange

Open Ocean

2 DIC2-6 DOC

3-7 TOC

?4.3

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Lots of progress made,but still much to do

• Constrain air-water CO2 flux for estuaries close inorganic C budget

• Burial measurements• Tracer techniques to get NEP on shelf and

cross-shelf transport• Numerical model evaluation and application

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Thank you

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References

Bricker, S.B., Longstaff, B., Dennison, W., Jones, A., Boicourt, K., Wicks, C., Woerner, J., 2007. Effects of nutrient enrichment in the nation’s estuaries: A decade of change, NOAA Coastal Ocean Program Decision Analysis Series No. 26. National Centers for Coastal Ocean Science, Silver Spring, MD. 328 pp.

Childers, D.L., J.W. Day Jr, H. N. Mckellar (2002). Twenty More Years of Marsh and Estuarine Flux Studies: Revisiting Nixon (1980), M. P. Weinstein and D. A. Kreeger (eds), Concepts and Controversies in Tidal Marsh Ecology, Springer, Netherlands, 391-423.

Dunne, J. P., J. L. Sarmiento, and A. Gnanadesikan (2007), A synthesis of global particle export from the surface ocean and cycling through the ocean interior and on the seafloor, Global Biogeochem. Cycles, 21, GB4006, doi:10.1029/2006GB002907.

Najjar, R.G., Friedrichs, M.A.M., Cai, W.-J. (Editors), 2012. Report of the U.S. East Coast Carbon Cycle Synthesis Workshop, January 19-20, 2012, Ocean Carbon

and Biogeochemistry Program and North American Carbon Program, 34 pp.Shih, J.S., Alexander, R.B., Smith, R.A., Boyer, E.W., Schwarz, G.E., Chung, S., 2010. An

Initial SPARROW Model of Land Use and In-Stream Controls on Total Organic Carbon in Streams of the Conterminous United States, U.S. Geological Survey Open-File Report 2010–1276, 22 pp.

Stets, E.G. and R.G. Striegl (2012). Carbon export by rivers draining the conterminous United States. Inland Waters, vol. 2., pp. 177-184.