The carbon budget for
coastal waters of the
eastern United States
Outline
1. Importance
of coastal
ocean
2. NACP
R. Najjar, M. Friedrichs, W.-J. Cai,
Coastal
D. Butman,K. Kroeger, W. M. Kemp,
Synthesis
M. Herrmann, L. McCallister, Z.
3. East coast
Wang, S. Signorini, C. Pilskaln,
carbon
D. Burdige, P. Vlahos,
budget
R. Vaillancourt
1
Importance of the coastal ocean
(depth < 200 m, 4.7% of ocean area)
Pg C yr-1 % ocean
total
Primary
Production
Export
Production
Burial
6.5
12
2.0
21
0.67
86
Source: Dunne et al. (2007)
2
NACP-OCB Coastal Synthesis Activity
Objective: “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
3
(Mathis)
(Alin, Hales)
(Cai, Freidrichs, Najjar)
(Coble, Lohrenz)
4
Nationalatlas.gov
The carbon cycle of the coastal ocean
Tidal wetlands
NPP
Estuaries
Degassing River input
Continental shelf
Air-water
exchange
NPP, R
Respiration (R)
Burial
NPP, R
POC export
Open
Ocean
Resuspension
POC
Advective
exchange
DOC
DIC
Sediments
POC
BPP
DOC
DIC
Coastal zone
of the eastern
U.S.:
Head-of-tide
to shelf break
(~200 m)
Tidal
wetlands
Estuaries
Shelf
waters
%
Area
3
14
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)
83
6
River input
USGS
SPARROW LOADEST
statistical (Shih et al. (Stets and
models
2010)
Striegl 2012)
TOC
Tg C yr-1
GoM
0.57
MAB
1.45
SAB
1.86
East Coast 3.9
DIC
Tg C yr-1
0.30
1.63
0.56
2.5
Also using process-based model (DLEM—see Tian et al. poster)
7
Tidal
wetlands
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
New Jersey
Delaware
Bay
Delaware
8
Tidal wetlands budget (Tg C yr-1)
NPP
13-24
Degassing
3-19
Respiration
(R) = 5-21
Burial
1-2
Net uptake
5-10
Lateral
export
2
2-6
?
DIC
DOC
POC
NPP – R = TOC export + Burial
R – NPP = DIC export + Degassing
Empirical model (Childers et al. 2002) being adopted/refined
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Estuarine
processes
64 estuaries
Based on NOAA’s
National Estuarine
Eutrophication
Assessment survey
(Bricker et al. 2007)
• See Herrmann et al.
poster
• Net ecosystem
production (NEP =
NPP – R) function of
riverine DIN:TOC
loading ratio
• Burial function of
estuarine residence
time
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East coast
estuarine NEP
= -1.9 Tg C yr-1
Integrate
3.4
Estuarine organic C
budget (Tg C yr-1)
-1.9 NEP 0.6
0.9
Canada not included yet!
11
120 ± 30 Tg C yr-1 primary
production on continental shelf
Gulf of Maine (GoM)
Georges Bank + Nantucket
Shoals (GB + NS)
Mid-Atlantic
Bight (MAB)
South Atlantic
Bight (SAB)
34 ± 10
35 ± 10
47 ± 20
• Currently a literature
synthesis
• Also using satellite
algorithms and
numerical models
• Respiration poorly
constrained
12
Continental shelf air-sea exchange
(Signorini et al. poster)
Surface pCO2 algorithm
exploiting satellite data
Flux = f(DpCO2, wind, SST)
Algorithm pCO2
Uptake
Tg C yr-1
GoM
-0.1
GB+NS
1.3
MAB
2.1
SAB
1.0
East Coast
4.3
Observed pCO2
13
Continental shelf sediments
DIC 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
>8
Resuspension Benthic DIC +
POC burial
flux
DOC flux
12
14
1
14
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
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Overall US east coast budget
Tidal wetlands
NPP Degassing
13-24
3-19
Estuaries
Continental shelf
River input
3.9 TOC
Air-water
2.5 DIC
? exchange
Respiration (R)
5-21
2 DIC
2-6 DOC
-1.9 NEP
Burial
1-2
Sediments
4.3
120 NPP, ? R
3-7 TOC
POC export
>8
Resuspension
12
Advective
exchange
Burial
0.9
POC
1
DOC+DIC
14
Open
Ocean
BPP
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
17
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.
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