Lead Authors:
Lisamarie Windham-Myers, U.S. Geological Survey
Wei-Jun Cai, University of Delaware
Contributing Authors:
Simone R. Alin, NOAA Pacific Marine Environmental Laboratory
Andreas Andersson, Scripps Institution of Oceanography
Joseph Crosswell, Commonwealth Scientific and Industrial Research Organization
Kenneth H. Dunton, University of Texas, Austin
Jose Martin Hernandez-Ayon, Autonomous University of Baja California
Maria Herrmann, The Pennsylvania State University
Audra L. Hinson, Texas A&M University
Charles S. Hopkinson, University of Georgia
Jennifer Howard, Conservation International
Xinping Hu, Texas A&M University, Corpus Christi
Sara H. Knox, U.S. Geological Survey
Kevin Kroeger, U.S. Geological Survey
David Lagomasino, University of Maryland
Patrick Megonigal, Smithsonian Environmental Research Center
Raymond G. Najjar, The Pennsylvania State University
May-Linn Paulsen, Scripps Institution of Oceanography
Dorothy Peteet, NASA Goddard Institute for Space Studies
Emily Pidgeon, Conservation International
Karina V. R. Schäfer, Rutgers University
Maria Tzortziou, City University of New York
Zhaohui Aleck Wang, Woods Hole Oceanographic Institution
Elizabeth B. Watson, Drexel University
Expert Reviewer:
Camille Stagg, U.S. Geological Survey
Science Lead:
Raymond G. Najjar, The Pennsylvania State University
Review Editor:
Marjorie Friederichs, Virginia Institute of Marine Science
Federal Liaisons:
Zhiliang Zhu, U.S. Geological Survey
Authors wish to thank their respective funding agencies, including the U.S. Geological Survey LandCarbon Program, NASA Carbon Monitoring System Program (NNH14AY671 for Windham-Myers), and the National Science Foundation Division of Ocean Sciences (OCE 1238212, 1637630, and 1237140 for Hopkinson).

Tidal Wetlands and Estuaries

Table 15A.1. Summary of North American Carbon Dioxide Exchange Between Tidal Wetlands and the Atmosphere (Net Ecosystem Exchangea) from Continuous Measurementsb

System Name and Type Location EC/SC Year NEE (g C per m2 per year) Source
Pacific Coast
Rush Ranch, Suisun Bay, brackish marsh California EC 2014–2015 14 Bergamaschi and Windham-Myers (2018)
2015–2016 –190
2016–2017 –222
Atlantic Coast
Plum Island, salt marsh Massachusetts EC 2012 –255.6 Forbrich and Giblin (2015)
2013 –336.0
2014 –279.6
Waquoit Bay, salt marsh Massachusetts SC 2015 –160.0 Moseman-Valtierra et al. (2016)
Hudson-Raritan Estuary, restored salt marsh New Jersey EC 2009 984c Schäfer et al. (2014)
2011 –64.8
2012 –309.6
Hudson-Raritan Estuary, restored salt marsh New Jersey EC 2011–2012 –213.6 Artigas et al. (2015)
Delaware Bay, tidal fresh marsh New Jersey SC 2007 –256.8 Weston et al. (2014)
2008 61.2
Delaware Bay, oligohaline marsh New Jersey SC 2007 93.6 Weston et al. (2014)
2008 –45.6
Delaware Bay, mesohaline marsh New Jersey SC 2007 –115.2 Weston et al. (2014)
2008 –171.6
Fowling Point, salt marsh Virginia SC 2007 –129.6 Kathilankal et al. (2008)
Springfield Creek, tidal fresh marsh South Carolina SC 2009 –295.2 Neubauer et al. (2013)
Gulf of Mexico
Pointe-aux-Chenes, brackish marsh Louisiana EC 2011 –337.2 Holm et al. (2016)
Salvador, tidal fresh marsh Louisiana EC 2011 170.4 Holm et al. (2016)
Florida Bay, mangrove Florida EC 2004 –1172.4 Barr et al. (2010);
Barr et al. (2012)
2005 –1176
2007 –823.2
2008 –806.4
2009 –926.4
Mobile Bay, tidal fresh marsh Alabama SC 2011 893.4 Wilson et al. (2015)
Mobile Bay, brackish marsh Alabama SC 2011 517.8 Wilson et al. (2015)
Mobile Bay, salt marsh Alabama SC 2011 410.2 Wilson et al. (2015)

Notes
a NEE, Net ecosystem exchange; g C, grams of carbon.
b Continuous measurements: eddy covariance (EC) or static chamber (SC). Positive values = atmospheric carbon dioxide (CO2) source. Negative values = atmospheric CO2 sink. Annual estimate (mean) provided.
c Mudflat habitat (very little data available in literature).

Table 15A.2. Tidal Wetland Methane Flux by Discrete Static Chamber Data or Continuous Eddy Covariancea Data

`
Site Name Location Year EC/SC Salinity (PSUb) CH4 Flux (g C per m2 per year)c Reference
Atlantic Coast

Upland edge

High marsh

Middle marsh

Low marsh

New Brunswick 1993 SC

23.5

31.6

33.7

35.1

1.0

0.2

0.2

0.2

Magenheimer et al. (1996)

Dipper Harbour

Kouchibouguac

New Brunswick 2011–2012 SC

23.7

13.7

0.1

0.0

Chmura et al. (2016)

Creek Bank

High marsh

Short Spartina

Virginia 1981–1983 SC

18.7

22.6

26.3

0.9

0.3

1.0

Bartlett et al. (1985)

Site 1

Site 2

Site 3

Virginia

1983–1984

1983–1984

1983–1984

SC

SC

SC

5.1

12.8

16.6

13.7

16.8

4.2

Bartlett et al. (1987)
Sweet Hall Virginia 1996–1997 SC 0.25 72.0 Neubauer et al.s (2000)

C3 Ambient CO2

C4 Ambient CO2

Maryland

Maryland

1998–1999

1998–1999

SC

SC

6.8

6.8

3.5

2.5

Marsh et al. (2005)

Tidal freshwater marsh

Oligohaline marsh

Mesohaline marsh

Delaware

2007

2008

2007

2008

2007

2008

SC

0.25

0.25

2.5

2.5

10

10

20.0

24.0

123.0

87.0

–5.0

–2.0

Weston et al. (2014)

Wildlife

Barbados

Maryland

Maryland

2008

2008

SC

SC

11.6

12.9

23.0

24.0

Poffenbarger et al. (2011)

Vegetated low marsh

Mud flat

New Jersey

2012

2012

SC

SC

5

5

4.3

3.8

Reid et al., (2013)

Fox Creek Marsh

Kirkpatrick Marsh

Maryland 2013–2014 SC

10

10

10

10

10

10

79.1

3.9

0.8

10.1

3.4

2.3

Mueller et al. (2016)

GI Near Bank

GI Far Bank

UF Near Bank

UF Far Bank

North Carolina 1990–1991 SC

0.25

0.25

0.25

0.25

6.2

4.3

3.8

2.6

Kelley et al. (1995)

Lower site

Upper site

North Carolina 1994–1995 SC

0.25

0.25

1.0

1.4

Megonigal and Schlesinger (2002)

Upper

Middle

Lower

Georgia

Georgia

Georgia

2006–2007

2006–2007

2006–2007

SC

SC

SC

0.2

1.3

4.7

0.8

1.0

1.0

Krass and Whitbeck (2011)
Georgia Coastal Ecosystems LTERd Georgia 2008–2009 SC 1 69.8 Segarra et al. (2013)
Brookgreen Gardens South Carolina 2009 SC 0.05 42.0 Neubauer et al. (2013)
Gulf of Mexico

Fresh

Brackish

Salt Marsh

Louisiana 1980–1981 SC

0.4

1.8

18.1

160.0

73.0

4.3

DeLaune et al. (1983)

Brackish marsh

Freshwater marsh

Louisiana

2012

2012

2013

EC

EC

EC

9.15

0.23

0.23

10.4

47.3

46.2

Holm et al. (2016)

Brackish marsh

Freshwater marsh

Louisiana 2012–2013

EC

SC

EC

SC

9.15

9.15

0.23

0.23

11.1

49.6

47.1

91.9

Krauss et al. (2016)

Week’s Bay

Dog River

Dauphin Island

Alabama 2012–2013 SC

2.3

4.7

20.7

7.9

3.9

4.3

Wilson et al. (2015)

Notes
a CH4, methane; CO2, carbon dioxide; SC, static chamber; EC, eddy covariance; g C, grams of carbon.
b Salinity values in bold indicate porewater salinity; otherwise, channel salinity is reported (where PSU = practical salinity units). When salinity was not reported for tidal freshwater wetlands, a value of 0.25 was assigned, which represents the midpoint of their salinity range (0 to 0.5) by definition.
c Positive values = atmospheric CH4 source. Negative values = atmospheric CH4 sink. Annual estimate provided.
d LTER, Long-term ecological research.

Table 15A.3. Estuarine Carbon Dioxide Outgassing (Emissions) for the U.S. Pacific Coast, Atlantic Coast,a and Gulf of Mexico Regionsb,c

System Name Location Subregion Source CO2 Flux (g C per m2 per year)c CO2 Flux Integral (Tg C per year)
Pacific Coast: Northwest
Columbia River Oregon, WA Northwest Evans et al. (2012) 12 NAd
Atlantic Coast: Gulf of Maine (GOM) Subregiona
Bellamy Estuary Massachusetts, USA GOM Hunt et al. (2011) 55
Cocheco Estuary Massachusetts, USA GOM Hunt et al. (2011) 44
Great Bay Massachusetts, USA GOM Hunt et al. (2011) 43
Kennebec Estuary Massachusetts, USA GOM Hunt et al. (2014) 30
Little Bay Massachusetts, USA GOM Hunt et al. (2011) 48
Oyster Estuary Massachusetts, USA GOM Hunt et al. (2011) 48
Parker River Massachusetts, USA GOM Raymond and Hopkinson (2003) 13
Mean 40 0.22
Standard error 5 0.03
Atlantic Coast: Mid-Atlantic Bight (MAB) Subregiona
Delaware River Delaware/ New Jersey, USA MAB Joesoef et al. (2015) 29
York River Virginia, USA MAB Raymond et al. (2000) 67
Mean 48 1.0
Standard error 19 0.4
Atlantic Coast: South Atlantic Bight (SAB) Subregiona
Altamaha Sound Georgia, USA SAB Jiang et al. (2008) 322
Doboy Sound Georgia, USA SAB Jiang et al. (2008) 143
Duplin River Georgia, USA SAB Wang and Cai (2004) 256
Neuse River N. Carolina, USA SAB Crosswell et al. (2012); Crosswell et al. (2014) –68
Pamlico Sound N. Carolina, USA SAB Crosswell et al. (2014) –180
Sapelo Sound Georgia, USA SAB Jiang et al. (2008) 126
Satilla River Georgia, USA SAB Cai and Wang (1998) 510
Mean 158 1.9
Standard error 88 1.1
Atlantic Coast Totals
Mean 82 3.1
Standard error 30 1.1
Gulf of Mexico (GMx)
Atchafalaya River Louisiana, USA GMx Huang et al. (2015) 504
Florida Bay Florida, USA GMx Zhang and Fischer (2014) 47
Mission-Aransas Estuary Texas, USA GMx Yao and Hu (2017) 149
Mississippi River Louisiana, USA GMx Huang et al. (2015) 444
Shark River Florida, USA GMx Kone and Borges (2008) 192
Terrebonne Bay Louisiana, USA GMx Huang et al. (2015) –4
Mean 222 6.8
Standard error 85 2.6
Atlantic Coast and Gulf of Mexico Totals
Mean 9.9
Standard error 2.8

Notes
a The Atlantic Coast is subdivided into three subregions: Gulf of Maine, Mid-Atlantic Bight, and South Atlantic Bight.
b Positive values = atmospheric CO2 source; negative values = atmospheric CO2 sink. A spatially representative annual CO2 flux integral is not calculated for the Pacific Coast due to the presence of only one study and limited seasonal sampling.
c CO2, carbon dioxide; g C, grams of carbon; Tg C, teragrams of carbon.
d NA (or blank): Not assessed.


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