Advertisement

Estuaries and Coasts

, Volume 34, Issue 5, pp 1084–1093 | Cite as

Beneath the Salt Marsh Canopy: Loss of Soil Strength with Increasing Nutrient Loads

  • R. Eugene TurnerEmail author
Article

Abstract

Although the broadly observed increase in nutrient loading rates to coastal waters in the last 100 years may increase aboveground biomass, it also tends to increase soil metabolism and lower root and rhizome biomass—responses that can compromise soil strength. Fourteen different multiyear field combinations of nutrient amendments to salt marshes were made to determine the relationship between soil strength and various nitrogen, phosphorus, and nitrogen+phosphorus loadings. There was a proportional decline in soil strength that reached 35% in the 60- to 100-cm soil layer at the highest loadings and did not level off. These loading rates are equivalent to those in the flow path of the Caernarvon river diversion, a major wetland restoration project near New Orleans; 12% of the wetlands in the flow path were converted to open water in 2005. The increased nutrient loading from the Mississippi River watershed this century has also driven the formation of the low oxygen zone (the “Dead Zone”) that forms off the Louisiana–Texas shelf each summer. These results suggest that improving water quality in the watershed will aid the restoration of both offshore waters and coastal wetland ecosystems.

Keywords

Wetland Soil strength Eutrophication Sustainability Louisiana 

Notes

Acknowledgments

Support was provided by the NOAA Coastal Ocean Program MULTISTRESS Award No. NA16OP2670 to Louisiana State University and from the Coastal Restoration and Enhancement through Science and Technology program. I thank J. Tripp, Environmental Defense Fund, for asking the pregnant question about the relationships between nutrient loading and soil quality, C. Swarzenski for comments on an earlier draft, and D. Daigle and C. Milan for their editorial review. The many, many constructive suggestions made by two anonymous reviewers are appreciated.

Conflict of Interest

I have no financial relationship with the organization that sponsored the research. I have full control of all primary data and agree to allow the journal to review the data if requested. There are no potential conflicts in the use of the data or financial conflicts.

References

  1. Bragazza, L., C. Freeman, T. Jones, R. Håkan, J. Limpens, N. Fenner, T. Ellis, R. Gerdol, M. Håjek, P. Iacumin, L. Kutnar, T. Tahvanainen, and H. Toberman. 2006. Atmospheric nitrogen deposition promotes carbon loss from peat bogs. Proceedings of the National Academy of Sciences of the United States of America 103: 19386–19389.CrossRefGoogle Scholar
  2. Broussard, W., and R.E. Turner. 2009. A century of changing land use and water quality relationships in the continental U.S. Frontiers in Ecology and the Environment 7: 302–307.CrossRefGoogle Scholar
  3. Chabreck, R. 1972. Vegetation, water and soil characteristics of the Louisiana coastal region. Louisiana Agricultural Experiment Station Bulletin 664. Baton Rouge, Louisiana.Google Scholar
  4. Coûteaux, M.-M., P. Bottner, and B. Berg. 1995. Litter decomposition, climate and litter quality. Trends in Ecology & Evolution 10: 63–66.CrossRefGoogle Scholar
  5. Costanza, R., O. Pérez-Maqueo, M.L. Martinez, P. Sutton, S.J. Anderson, and K. Mulder. 2008. The value of coastal wetlands for hurricane protection. Ambio 37: 241–248.CrossRefGoogle Scholar
  6. Darby, F.A., and R.E. Turner. 2008a. Effects of eutrophication on salt marsh roots, rhizomes, and soils. Marine Ecology Progress Series 363: 63–70.CrossRefGoogle Scholar
  7. Darby, F.A., and R.E. Turner. 2008b. Below- and aboveground biomass of Spartina alterniflora: Response to nutrient addition in a Louisiana salt marsh. Estuaries and Coasts 31: 326–334.CrossRefGoogle Scholar
  8. Deegan, L.A., and 18 co-authors. 2010. Susceptibility of salt marshes to nutrient enrichment and predator removal. Ecological Applications 17: 542–563.Google Scholar
  9. Eggelsmann, R. 1976. Peat consumption under influence of climate, soil condition, and utilization. In Proceedings International Peat Congress. 1: 233–247. International Peat Society Poznan, Poland.Google Scholar
  10. Franzen, L.G. 2006. Increased decomposition of subsurface peat in Swedish raised bogs: Are temperate peatlands still net sinks of carbon? Mires and Peat 3: 1–16.Google Scholar
  11. Gill, R.A., and R.B. Jackson. 2000. Global patterns of root turnover for terrestrial ecosystems. The New Phytologist 147: 13–31.CrossRefGoogle Scholar
  12. Graphpad Software Inc. 2005. Graphpad prism, ver. 4.0. CA: Graphpad Software, Inc.Google Scholar
  13. Hamersley, M.R., and B.L. Howes. 2005. Coupled nitrification–denitrification measured in situ in a Spartina alterniflora marsh with a (NH4+)-N-15 tracer. Marine Ecology Progress Series 299: 123–135.CrossRefGoogle Scholar
  14. Harris, C.I., H.T. Erickson, N.K. Ellis, and J.E. Larson. 1962. Water-level control in organic soil, as related to subsidence rate, crop yield, and response to nitrogen. Soil Science 94: 158–161.CrossRefGoogle Scholar
  15. Holm, G.O. 2006. Nutrient constraints on plant community production and organic matter accumulation of subtropical floating marshes. Ph.D. dissertation, Louisiana State University, Baton Rouge, Louisiana.Google Scholar
  16. Huang, X., and J.T. Morris. 2005. Distribution of phosphatase activity in marsh sediments along an estuarine salinity gradient. Marine Ecology Progress Series 292: 75–83.CrossRefGoogle Scholar
  17. Hyfield, E.C.G., J.W. Day, J.E. Cable, and D. Justic. 2008. The impacts of re-introducing Mississippi River water on the hydrologic budget and nutrient inputs of a deltaic estuary. Ecological Engineering 32: 347–359.CrossRefGoogle Scholar
  18. Langley, J.A., K.L. McKee, D.R. Cahoon, J.A. Cherry, and P. Megonigal. 2009. Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise. Proceedings of the National Academy of Sciences of the United States of America 106: 6182–6186.Google Scholar
  19. Laursen, K.R. 2004. The effects of nutrient enrichment on the decomposition of belowground organic matter in a Sagittaria lanciffolia-dominated oligohaline marsh. M.S. thesis, Louisiana State University, Baton Rouge, Louisiana.Google Scholar
  20. Levin, S.A., H.A. Mooney, and C. Field. 1989. The dependence of plant root:shoot ratios on internal nitrogen concentration. American Journal of Botany 64: 71–75.Google Scholar
  21. Lovelace, J.K., B.F. McPherson. 1998. Effects of Hurricane Andrew (1992) on wetlands in southern Florida and Louisiana. U.S. Geological Survey, National Water Summary on Wetland Resources. U.S.G.S. Water Supply Paper 2425. http://water.usgs.gov/nwsum/WSP2425/andrew.html. Accessed 16 Feb 2010.
  22. Mack, M.C., E.A.G. Schuur, M.S. Bret-Harte, R. Shaver, and S. Chaplin III. 2004. Ecosystem carbon storage in arctic tundra reduced by long-term nutrient fertilization. Nature 431: 440–443.CrossRefGoogle Scholar
  23. Mendelssohn, I.A., K.L. McKee, and W.H. Patrick Jr. 1981. Oxygen deficiency in Spartina alterniflora roots: Metabolic adaptation to anoxia. Science 214: 439–441.CrossRefGoogle Scholar
  24. Milan, C.S., E.M. Swenson, R.E. Turner, and J.M. Lee. 1995. Accumulation rates estimated from 137Cs activity: Variability in Louisiana salt marshes. Journal of Coastal Research 11: 296–307.Google Scholar
  25. Morris, J.T. 1991. Effects of nitrogen loading on wetland ecosystems with particular reference to atmospheric deposition. Annual Review of Ecology and Systematics 22: 257–279.CrossRefGoogle Scholar
  26. Morris, J.T., and P. Bradley. 1999. Effects of nutrient loading on the carbon balance of coastal wetland environments. Limnology and Oceanography 44: 699–702.CrossRefGoogle Scholar
  27. Morris, J.T., P.V. Sundareshwar, C.T. Nietch, B. Kjerfve, and D.R. Cahoon. 2005. Responses of coastal wetlands to rising sea level. Ecology 83: 2869–2877.CrossRefGoogle Scholar
  28. National Research Council (NRC). 2000. Clean coastal waters. Understanding and reducing the effects of nutrient pollution. Washington: National Academy Press.Google Scholar
  29. Newman, S., H. Kumpf, J.A. Laning, and W.C. Kennedy. 2001. Decomposition responses to phosphorus in an Everglades (USA) slough. Biogeochemistry 54: 299–250.CrossRefGoogle Scholar
  30. Parsons, M.L., Q. Dortch, R.E. Turner, and N.N. Rabalais. 2006. Reconstructing the development of eutrophication in Louisiana salt marshes. Limnology and Oceanography 151: 534–544.CrossRefGoogle Scholar
  31. Penton, C.R., and S. Newman. 2007. Enzyme activity responses to nutrient loading in subtropical wetlands. Biogeochemistry 84: 83–98.CrossRefGoogle Scholar
  32. Penton, C.R., and S. Newman. 2008. Enzyme-based resource allocated decomposition and landscape heterogeneity in the Florida Everglades. Journal of Environmental Quality 37: 972–976.CrossRefGoogle Scholar
  33. Qualls, R.G., and C.J. Richardson. 2008. Decomposition of litter and peat in the Everglades: The influence of P concentrations. In The Everglades experiments, ed. C.J. Richardson, 441–459. New York: Springer.Google Scholar
  34. Rabalais, N.N., R.E. Turner, and D. Scavia. 2002. Beyond science into policy: Gulf of Mexico hypoxia and the Mississippi River. Bioscience 52: 129–142.CrossRefGoogle Scholar
  35. Rabalais, N.N., R.E. Turner, B.K. Sen Gupta, D.F. Boesch, P. Chapman, and M.C. Murrell. 2007. Hypoxia in the northern Gulf of Mexico: Does the science support the plan to reduce, mitigate and control hypoxia? Estuaries and Coasts 30: 753–772.Google Scholar
  36. Reimold, R.J. 1972. The movement of phosphorus through the salt marsh cord grass, Spartina alterniflora Loisel. Limnology and Oceanography 17: 606–611.CrossRefGoogle Scholar
  37. Swarzenski, C.M., T.W. Doyle, B. Fry, and T.G. Hargis. 2008. Biogeochemical response of organic-rich freshwater marshes in the Louisiana delta plain to chronic river water influx. Biogeochemistry 90: 49–63.CrossRefGoogle Scholar
  38. Slocum, M.G., J. Roberts, and I.A. Mendelssohn. 2009. Artist canvas as a new standard for the cotton-strip assay. Journal of Plant Nutrition and Soil Science 172: 71–74.CrossRefGoogle Scholar
  39. Sundareshwar, P.V., J.T. Morris, E.K. Koepfler, and B. Formwalt. 2003. Phosphorus limitation of coastal ecosystem processes. Science 299: 563–565.CrossRefGoogle Scholar
  40. Turner, R.E. 2010. Doubt and the values of an ignorance-based world view for wetland restoration: Coastal Louisiana. Estuaries and Coasts 32: 1054–1068.CrossRefGoogle Scholar
  41. Turner, R.E., J.J. Baustian, E.M. Swenson, and J.S. Spicer. 2006. Wetland sedimentation from hurricanes Katrina and Rita. Science 314: 449–452.CrossRefGoogle Scholar
  42. Turner, R.E., B.L. Howes, J.M. Teal, C.S. Milan, E.M. Swenson, and D. Goehringer-Toner. 2009. Salt marshes and eutrophication: An unsustainable outcome. Limnology and Oceanography 54: 1634–1642.CrossRefGoogle Scholar
  43. Turner, R.E., and N.N. Rabalais. 2003. Linking landscape and water quality in the Mississippi River Basin for 200 years. Bioscience 53: 563–572.CrossRefGoogle Scholar
  44. 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. Weinstein and D. Kreeger, 583–595. Dordrecht: Kluwer.Google Scholar
  45. U.S. Government Accountability Office. 2007. Coastal wetlands: Lessons learned from past efforts in Louisiana could help guide future restoration and protection. Washington: U.S. Printing Office, GAO-180.Google Scholar
  46. White, J.R., and K.R. Reddy. 2000. Influence of phosphorus loading on organic nitrogen mineralization of Everglades soils. Soil Science Society of America Journal 64: 1525–1534.CrossRefGoogle Scholar
  47. Wigand, C., P. Brennan, M. Stolt, M. Hoh, and S. Ryba. 2009. Soil respiration rates in coastal marshes subject to increasing watershed nitrogen loads in southern New England, US. Wetlands 29: 952–963.CrossRefGoogle Scholar

Copyright information

© Coastal and Estuarine Research Federation 2010

Authors and Affiliations

  1. 1.Coastal Ecology Institute, and, Department of Oceanography and Coastal SciencesLouisiana State UniversityBaton RougeUSA

Personalised recommendations