Carbon Sequestration and Sediment Accretion in San Francisco Bay Tidal Wetlands
- 1.5k Downloads
Tidal wetlands play an important role with respect to climate change because of both their sensitivity to sea-level rise and their ability to sequester carbon dioxide from the atmosphere. Policy-based interest in carbon sequestration has increased recently, and wetland restoration projects have potential for carbon credits through soil carbon sequestration. We measured sediment accretion, mineral and organic matter accumulation, and carbon sequestration rates using 137Cs and 210Pb downcore distributions at six natural tidal wetlands in the San Francisco Bay Estuary. The accretion rates were, in general, 0.2–0.5 cm year−1, indicating that local wetlands are keeping pace with recent rates of sea-level rise. Mineral accumulation rates were higher in salt marshes and at low-marsh stations within individual sites. The average carbon sequestration rate based on 210Pb dating was 79 g C m−2 year−1, with slightly higher rates based on 137Cs dating. There was little difference in the sequestration rates among sites or across stations within sites, indicating that a single carbon sequestration rate could be used for crediting tidal wetland restoration projects within the Estuary.
KeywordsBrackish marsh Carbon offsets Climate change Mineral matter accumulation Organic matter accumulation Salt marsh San Francisco Bay Estuary Sea-level rise Sedimentation
We thank the Gordon and Betty Moore Foundation for financial support for this research project. Site access and other support were provided by the California Department of Fish and Game, California State Coastal Conservancy, California State Parks, Don Edwards San Francisco Bay National Wildlife Refuge, East Bay Regional Park District, San Francisco Bay National Estuarine Research Reserve, and Solano Land Trust. Field and lab assistance was provided by Jennifer Gagnon, Mark Rosasco, and Andrea Torres. Valuable comments were provided on the manuscript by Steve Crooks, Judy Drexler, and two anonymous reviewers.
- Atwater, B.F., S.G. Conard, J.N. Dowden, C.W. Hedel, R.L. MacDonald, and W. Savage. 1979. History, landforms, and vegetation of the estuary’s tidal marshes. In San Francisco Bay: the urbanized estuary, ed. T.J. Conomos, 347–385. San Francisco: Pacific Division, American Association for the Advancement of Science.Google Scholar
- Beckley, B.D., F.G. Lemoine, S.B. Luthcke, R.D. Ray, and N.P. Zelensky. 2007. A reassessment of global and regional mean sea level trends from TOPEX and Jason-1 altimetry based on revised reference frame and orbits. Geophysical Research Letters 34: Article no. L14608. doi:14610.11029/12007gl030002.
- Callaway, J.C. 2001. Hydrology and substrate. In Handbook for restoring tidal wetlands, ed. J.B. Zedler, 89–117. Boca Raton: CRC.Google Scholar
- Callaway, J.C., A.B. Borde, H.L. Diefenderfer, V.T. Parker, J.M. Rybcyzk, and R.M. Thom. 2012. Pacific Coast tidal wetlands. In Wetland habitats of North America: ecology and conservation concerns, eds. D. P. Batzer and A. H. Baldwin, 103–116. Berkeley, CA: University of California Press.Google Scholar
- Callaway, J.C., R.D. DeLaune, and W.H. Patrick Jr. 1997. Sediment accretion rates from four coastal wetlands along the Gulf of Mexico. Journal of Coastal Research 13: 181–191.Google Scholar
- Callaway, J.C., J.A. Nyman, and R.D. DeLaune. 1996b. Sediment accretion in coastal wetlands: a review and a simulation model of processes. Current Topics in Wetland Biogeochemistry 2: 2–23.Google Scholar
- Chmura, G.L., S.C. Anisfeld, D.R. Cahoon, and J.C. Lynch. 2003. Global carbon sequestration in tidal, saline wetland soils. Global Biogeochemical Cycles 17: Article no. 1111. doi:1110.1029/2002GB001917
- Crooks, S., S. Emmett-Mattox, and J. Findsen. 2010. Findings of the National Blue Ribbon Panel on the Development of a Greenhouse Gas Offset Protocol for Tidal Wetlands Restoration and Management: action plan to guide protocol development: Restore America’s Estuaries, Philip Williams & Associates, Ltd., and Science Applications International Corporation. http://estuaries.org/climate-change.html. Accessed 3 Feb 2012.
- Emmett-Mattox, S., S. Crooks, and J. Findsen. 2011. Gases and grasses: the restoration, conservation, or avoided loss of tidal wetlands carbon pools may help to mitigate climate change. The Environmental Forum 28: 30–35.Google Scholar
- French, J.R., T. Spencer, A.L. Murray, and N.S. Arnold. 1995. Geostatistical analysis of sediment deposition in two small tidal wetlands, Norfolk, U.K. Journal of Coastal Research 11: 308–321.Google Scholar
- Friedrichs, C.T., and J.E. Perry. 2001. Tidal salt marsh morphodynamics: a synthesis. Journal of Coastal Research Special Issue 27: 7–37.Google Scholar
- Gee, G.W., and J.W. Bauder. 1986. Particle-size analysis. In Methods of soil analysis: Part I: Physical and mineralogical methods, ed. A. Klute, 383–411. Madison: American Society of Agronomy.Google Scholar
- Hansen, L.T. 2009. The viability of creating wetlands for the sale of carbon offsets. Journal of Agricultural and Resource Economics 34: 350–365.Google Scholar
- Hargis, T.G., and R.R. Twilley. 1994. Improved coring device for measuring soil bulk density in a Louisiana deltaic marsh. Journal of Sedimentary Research Section A: Sedimentary Petrology and Processes 64: 681–683.Google Scholar
- Horowitz, A.J. 2010. A quarter century of declining suspended sediment fluxes in the Mississippi River and the effect of the 1993 flood. Hydrological Processes 24: 13–34.Google Scholar
- IPCC. 2007. Climate change 2007: The physical science basis: summary for policymakers. www.ipcc.ch. Accessed 3 Feb 2012.
- Kirwan, M.L., G.R. Guntenspergen, A. D’Alpaos, J.T. Morris, S.M. Mudd, and S. Temmerman. 2010. Limits on the adaptability of coastal marshes to rising sea level. Geophysical Research Letters 37: Article no. L23401. doi:23410.21029/22010gl045489
- Laffoley, D., and G. Grimsditch (eds.). 2009. The management of natural coastal carbon sinks. Gland: IUCN.Google Scholar
- McLeod, E., G.L. Chmura, S. Bouillon, R. Salm, M. Björk, C.M. Duarte, C.E. Lovelock, W.H. Schlesinger, and B.R. Silliman. 2011. A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Frontiers in Ecology and the Environment 9: 552–560.CrossRefGoogle Scholar
- Milan, C.S., E.M. Swenson, R.E. Turner, and J.M. Lee. 1995. Assessment of the 137Cs method for estimating sediment accumulation rates: Louisiana salt marshes. Journal of Coastal Research 11: 296–307.Google Scholar
- Pethick, J.S. 1981. Long-term accretion rates on tidal salt marshes. Journal of Sedimentary Petrology 51: 521–577.Google Scholar
- Reed, D.J. 2002. Understanding tidal marsh sedimentation in the Sacramento–San Joaquin Delta, California. Journal of Coastal Research Special Issue 36: 605–611.Google Scholar
- Rybcyzk, J.M., and J.C. Callaway. 2009. Surface elevation models. In Coastal wetlands: an integrated ecosystem approach, ed. G.M.E. Perillo, E. Wolanski, D.R. Cahoon, and M.M. Brinson, 835–854. Amsterdam: Elsevier Science.Google Scholar
- Stevenson, J.C., L.G. Ward, and M.S. Kearney. 1986. Vertical accretion in marshes with varying rates of sea level rise. In Estuarine variability, ed. D.A. Wolfe, 241–259. San Diego: Academic.Google Scholar
- SYSTAT Software Inc. 2007. SYSTAT 12. Chicago: SYSTAT Software, Inc.Google Scholar
- Turner, R.E., E.M. Swenson, and C.S. Milan. 2000. Organic and inorganic contributions to vertical accretion in salt marsh sediments. In Concepts and controversies in tidal marsh ecology, ed. M.P. Weinstein and D.A. Kreeger, 583–595. Boston: Kluwer Academic.Google Scholar
- Williams, P.B., and P.M. Faber. 2001. Salt marsh restoration experience in the San Francisco Bay estuary. Journal of Coastal Research Special Issue 27: 203–211.Google Scholar
- Wright, S.A., and D.H. Schoellhamer. 2004. Trends in the sediment yield of the Sacramento River, California, 1957–2001. San Francisco Estuary and Watershed Science 2: Article 2. http://repositories.cdlib.org/jmie/sfews/vol2/iss2/art2. Accessed 3 Feb 2012.