1 / 20

Rachel Hatch April 27, 2012

Impacts of sea level rise on sedimentation in tidal salt marsh settings of the Coastal Plain, U.S.A. Rachel Hatch April 27, 2012. Outline. Tidal salt marshes Importance U.S. Coastal Plain Development and sedimentation Sea level interactions Methods Conclusions.

lilac
Télécharger la présentation

Rachel Hatch April 27, 2012

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Impacts of sea level rise on sedimentation in tidal salt marsh settings of the Coastal Plain, U.S.A. Rachel Hatch April 27, 2012

  2. Outline • Tidal salt marshes • Importance • U.S. Coastal Plain • Development and sedimentation • Sea level interactions • Methods • Conclusions

  3. What is a tidal salt marsh? • Transitions between land and sea • Located in intertidal zone • At least occasionally inundated by high tide, but not flooded during low tide • A gentle shoreline slope allows for tidal flooding and the stability of the vegetation • Adequate protection from wave and storm energy is a physical requirement for development

  4. Importance • Serve many functions: • Slow shoreline erosion • Filter and absorb excess nutrients and pollutants • Provide a habitat for fish, birds and invertebrates • Over 50% of U.S. population lives in coastal communities • Represents only 10% of U.S. land mass • Heavy development associated with dense populations • Unprecedented losses of coastal marshlands over last century due in part to human activities

  5. U.S. Coastal Plains • Frequently associated with temperate coastal plains and deltaic deposits • Coastal Plain of U.S. extends from New Jersey along southeastern coast to Texas along Gulf Coast • Composed of Cretaceous to Quaternary sedimentary deposits • Later uplifted and tilted seaward • Major rivers supply abundance of silt and marshes are laced with tidal creeks • Gulf Coast contains about 60% of U.S. coastal marshland http://www.nationalatlas.gov/articles/geology/features/coastalplain.html

  6. Development and Sedimentation • Trap and accumulate sediment through two processes: • Surface sediment deposition • Subsurface accumulation of plant material • Sedimentation enhances plant growth, and vegetation in turn enhances sedimentation by trapping suspended sediments • Stability controlled by relative rates of marsh sediment accretion and surface subsidence http://www.usgcrp.gov/usgcrp//Library/nationalassessment/18CO.pdf

  7. Sea Level Rise • IPCC projected century-end sea levels using estimates of future social and economic development • Estimate sea level rise to be 2.8 mm/yr • Disregard possible influence of large ice sheet melt • Satellite altimetry data shows average rate of 3.4 mm/yr since 1993 • Ice sheets changing more rapidly than expected, so sea level will actually rise ~1 meter by 2100! • What would this mean? • In Louisiana, 1.2 million people live at elevation of less than 3 meters • 90% of New Orleans would be completely submerged

  8. http://www.geo.arizona.edu/dgesl/research/research.htm

  9. How do we learn about marsh accretion? • Radionuclides • Pollen analysis • Storm lenses • Pollution • Historical records • Foraminiferal assemblages • Artificial surface markers

  10. Lead-210 Dating • Particle-reactive radionuclide • ½ life = 22 yrs • Naturally occurring • Daughter in Uranium-238 decay series • Bound to sediments and deposited • Constant Flux Model http://www.microanalytica.com/slics/

  11. Cesium-137 Dating • ½ life = 30 yrs • Artificial radionuclide • Produced from aboveground nuclear weapons testing • Deposited from atmosphere and adsorbed onto sediments • Peaks of 1953 (first instance) and 1963 used to date sediment

  12. But HOW does sea level affect marshes? • Soil accretion < sea level rise • Inundation leads to waterlogging • Plants sensitive to salinity die back • Decreased plant biomass leads to less material available for sedimentation • Submergence or transition to mudflat http://coffeewithhallelujah.blogspot.com/

  13. Mississippi River Delta • Sea level rise presently exceeds accretion • Two major contributors to erosional problems: • Subsidence caused by compaction and natural downwarping of crust • Controlled discharge of river • Suspended sediment concentrations decreased by 70% since 1850 • Construction of dams and reservoirs • Results in deficiency of sediment to support vegetative growth

  14. Mississippi River Delta • Relative SL rise currently 10 mm/yr • Accretion would have to be double rates in other parts of US • In actuality, marshes show negative balance between sedimentation and SL rise • Contributed to loss of 4000 km2 of salt marsh over last century • Microtidalregime • Tidal range < 2 m • Wave-dominated • Highly susceptible to sea level changes D’Alpaoset al., 2011

  15. Conclusions • Sea level has been relatively stable over the last 5000 years, but is expected to rise significantly over the next 100 • Response of tidal salt marshes is dependent on ability to maintain elevation through vertical accretion • Rise in sea level combined with natural subsidence is likely to lead to drowning of salt marshes • Remains difficult to quantitatively assess potential effects of rising sea level in face of continuing human-induced disturbances • More research needed so coastal management practices can be adapted accordingly

  16. Questions? http://coffeewithhallelujah.blogspot.com/

  17. REFERENCES: • Bricker-Urso, S., Nixon, S.W., Cochran, J.K., Hirschberg, D.J., Hunt, C., 1989. Accretion rates and sediment accumulation in Rhode Island salt marshes. Estuaries 12(4), 300-317. • Brush, G.R., Martin, E.A., DeFries, R.S., Rice, C.A., 1982. Comparisons of 210Pb and pollen methods for determining rates of estuarine sediment accumulation. Quaternary Research 18, 196–217. • Burns, K.A., Ehrhardt, M.G., Howes, B.L., Taylor, C.D., 2003. Subtidal benthic community respiration and production near the heavily oiled Gulf Coast of Saudi Arabia. Marine Pollution Bulletin 27, 199-205. • Cabanes C., Cazenave A., Le Provost C., 2001. Sea level rise during past 40 years determined from satellite and in situ observations. Science 294, 840–842. • Cahoon, D.R., Reed, D.J., Day, J.W., 1995. Estimating shallow subsidence in microtidal salt marshes of the southeastern United States: Kaye and Barghoorn revisited. Marine Geology 128, 1–9. • Cahoon, D.R., 1997. Global warming, sea-level rise, and coastal marsh survival. United States Geological Survey Fact Sheet 091-97. Retrieved from http://www.nwrc.usgs.gov/factshts/fs91_97.pdf. Viewed on 3 April 2012. • Cazenave, A., Llovel, W., 2010. Contemporary Sea Level Rise. The Annual Review of Marine Science 2, 145-173. • Chapman, V.J., 1960. Salt Marshes and Salt Deserts of the World. Interscience Publishing, Inc., New York. • Cooper, J.A.G., 2005. Microtidal coasts, In: Schwartz, M.L. (Ed.), Encyclopedia of Coastal Science. Springer, Dordrecht, The Netherlands, pp. 638. • Costanza, R., et al., 1997. The value of the world’s ecosystem services and natural capital. Nature 387, 253–260. • Crooks, S., Pye, K. 2000. Sedimentological controls on the erosion and morphology of saltmarshes: implications for flood defense and habitat restoration, In: Pye, K., Allen J.R.L. (Eds.), Coastal and estuarine environments: sedimentology, geomorphology and geoarchaeology. Geological Society, London, Special Publication 175, 207-222. • D’Alpaos, A., Mudd, S.M., Carniello, L., 2011. Dynamic response of marshes to perturbations in suspended sediment concentrations and rates of relative sea level rise. Journal of Geophysical Research 116, 13 p. • Day, J.W., Shaffer, G.P., Britsch, L.D., Reed, D.J., Hawes, S.R., Cahoon, D., 2000. Pattern and process of land loss in the Mississippi Delta: a spatial and temporal analysis of wetland habitat change. Estuaries 23, 425-438.

  18. DeLaune, R.D., Patrick, W.H., Buresh, R.J., 1978. Sedimentation rates determined by 137Cs dating in a rapidly accreting salt marsh. Nature 275: 532-533. • DeLaune, R.D., Nyman, J.A., Patrick, W.H., Jr., 1994. Peat collapse, ponding and wetland loss in a rapidly submerging coastal marsh. Journal of Coastal Research 10(4), 1021-1030. • Field, D.W., Reyer, A.J., Genovese, P.V., Shearer, B.D., 1991. Coastal Wetlands of the United States. National Oceanic and Atmospheric Administration and U.S. Fish and Wildlife Service, Washington, DC. • French, J.R., Burningham, H., 2003. Tidal marsh sedimentation versus sea-level rise: a southeast England estuarine perspective. Proceedings of the International Conference of Coastal Sediments 2003, Sheraton Sand Key Resort, Clearwater, Florida. • Grinsted, A., Moore, J.C., Jevrejeva, S., 2009. Reconstructing sea level from paleo and projected temperatures 200 to 2100 AD. Climate Dynamics 34, 461-472. • Hatton, R.S., DeLaune, R.D., Patrick, W.H., Jr., 1983. Sedimentation, accretion, and subsidence in marshes of Barataria Basin, Louisiana. Limnology and Oceanography 28(3), 494-502. • Hippensteel, S.P., 2005. Limiting the limits of bioturbation, or at least focusing on the positive. PALAIOS 20(4), 319-320. • Howes, N.C., FitzGerald, D.M., Hughes, Z. J., Georgiou, I.Y., Kulp, M.A., Miner, M.D., Smith, J.M., Barras, J.A., 2010. Hurricane-induced failure of low salinity wetlands. Proceedings of the National Academy of Sciences U.S.A. 107, 14014–14019. • Hughes, R.G., 1999. Saltmarsh erosion and the management of saltmarsh restoration: the effects of infaunal invertebrates. Aquatic Conservation: Marine and Freshwater Ecosystems 9, 83-95. • Hulme, M., Jenkins, G.J., Lu, X., Turnpenny, J.R., Mitchell, T.D., Jones, R.G., Lowe, J., Murphy, J.M., Hassell, D., Boorman, P., McDonald, R. and Hill, S., 2002. Climate Change Scenarios for the United Kingdom: The UKCIP02 Scientific Report. Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich, UK. • IPCC, 2007. Summary for Policymakers, In: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Avery, K.B., Tignor, M., Miller, H.L. (Eds.), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, USA. • Kennett, J.P., 1982. Sea-level history and seismic stratigraphy, in: Kennett, J.P. (Ed.), Marine Geology. Prentice Hall, Upper Saddle River, New Jersey, pp. 263-267.

  19. Kennish, M.J., 2001. Coastal salt marsh systems in the U.S.: a review of anthropogenic impacts. Journal of Coastal Research 17(3), 731-748. • Kesel, R.H., 1988. The decline in suspended load of the lower Mississippi River and its influence on adjacent wetlands. Environmental Geology and Water Science 11, 271-281. • Kim, D., Cairns, D.M., Bartholdy, J., 2011. Wind-driven sea-level variation influences dynamics of salt marsh vegetation. Annals of the Association of American Geographers 101(2), 231-248 • Kirwan, M. L., Guntenspergen, G.R., D’Alpaos, A., Morris, J.T., Mudd, S.M., Temmerman, S., 2010. Limits on the adaptability of coastal marshes to rising sea level. Geophysical Research Letters 37, 5 p. • Leorri, E., Martin, R.D., Horton, B.P., 2009. Field experiments on bioturbation in salt marshes (Bombay Hook National Wildlife Refuge, Smyrna, DE, USA): implications for sea-level studies. Journal of Quaternary Science 24(2), 139-149. • Mitsch, W.J., Gosselink, J.G., 2000. Wetlands, Third Ed. John Wiley & Sons, Toronto. • Mudd, S.M., Howell, S.M., Morris, J.T., 2009. Impact of dynamic feedbacks between sedimentation, sea-level rise, and biomass production on near-surface marsh stratigraphy and carbon accumulation. Estuarine, Coastal and Shelf Science: 1-13. • Mudd, S.M., 2011. The life and death of salt marshes in response to anthropogenic disturbance of sediment supply. Geology 39, 511-512. • National Atlas of the United States, 2011. The North American Tapestry of Time and Terrain: Coastal Plain. Retrieved from http://www.nationalatlas.gov. Viewed on 23 April 2012. • Orson, R.A., Panageotou, W., Leatherman, S.P., 1985. Response of tidal salt marshes of the U.S. Atlantic and Gulf coasts to rising sea levels. Journal of Coastal Research 1, 29-37. • Orson, R.A., Simpson, R.L., Good, R.E., 1990. Rates of sediment accumulation in a tidal freshwater marsh. Journal of Sedimentary Petrology 60, 859–869. • Orson, R.A., Warren, R.S., Niering, W.A., 1998. Interpreting sea level rise and rates of vertical marsh accretion in a Southern New England tidal salt marsh. Estuarine, Coastal and Shelf Science 47, 41-429. • Penland, S., Suter, J.R., 1989. The geomorphology of the Mississippi river chenier plain. Marine Geology 90, 231-58. • Penland, S., Ramsey, L.E., 1990. Relative sea-level rise in Louisiana and the Gulf of Mexico: 1908-1988. Journal Coastal Research 6, 323-342. • Pethick, J.S., 1980. Salt-marsh initiation during the Holocene transgression: the example of the North Norfolk marshes, England. Journal of Biogeography 7, 1-9.

  20. Reed, D.J., 1990. The impact of sea-level rise on coastal salt marshes. Progress in Physical Geography 14, 465-481. • Reed, D.J., 2002. Sea-level rise and coastal marsh sustainability: geological and ecological factors in the Mississippi delta plain. Geomorphology 48, 233-243. • Smoak, J.M., Patchineelam, S.R., 1999. Sediment mixing and accumulation in a mangrove ecosystem: evidence from 210Pb, 234Th and 7Be. Mangroves and Salt Marshes 3: 17–27. • Stevenson, J.C., Kearney, M.S., 2009. Impacts of global climate change and sea level rise on tidal wetlands, In: Silliman, B.R., Bertness, M.D., Strong, D. (Eds.), Anthropogenic modification of North American salt marshes. University of California Press, Berkeley. • U.S. Environmental Protection Agency (EPA), 2011. Future sea level changes. Retrieved from http://www.epa.gov/climatechange/science/futureslc.html. Viewed on 23 April 2012. • U.S. Global Change Research Program (USGCRP), 2000. Coastal areas and resources. Retrieved from http://www.usgcrp.gov/usgcrp//Library/nationalassessment/18CO.pdf. Viewed on 18 April 2012. • Valiela, I., Rutecki, D., Fox, S., 2004. Salt marshes: biological controls of food webs in a diminishing environment. Journal of Experimental Marine Biology and Ecology 300, 131-159. • Varekamp, J.C., Thomas, E., van de Plassche, O., 1992. Relative sea level rise and climate change over the last 1500 years. Terra Nova 4, 293–304. • Watzin, M.C., Gosselink, J.G., 1992. The Fragile Fringe: Coastal Wetlands of the Continental United States. Technical Report, Louisiana Sea Grant Program, Louisiana State University, Baton Rouge, Louisiana, U.S. Fish and Wildlife Service, Washington, D.C., and the National Oceanic and Atmospheric Administration, Rockville, Maryland. • Weiss, J.L., Overpeck, J.T., Strauss, B., 2011. Implications of recent sea level rise science for low-elevation areas in coastal cities of the conterminous U.S.A. Climatic Change 105, 635-645. • Williams, H.F.L., Hamilton, T.S., 1995. Sedimentary dynamics of an eroding tidal marsh derived from stratigraphic records of 137Cs fallout, Fraser Delta, British Columbia, Canada. Journal of Coastal Research 11(4): 1145-1156. • Yeager, K.M., Santschi, P.H., Schindler, K.J., Andres, M.J., Weaver, E.A., 2006. The relative importance of terrestrial versus marine sediment sources to the Nueces-Corpes Christi Estuary, Texas: an isotopic approach. Estuaries and Coasts 29: 443-454.

More Related