1. Global Warming, Sea Level Rise, and Coastal Wetland Sustainability John Rybczyk Huxley College of the Environment Western Washington University

3. Predicted Contributions to Sea Level Rise Over the Next 100 years Thermal Expansion of the Oceans Melting of Alpine Glaciers Melting of Greenland Ice Sheet Antarctic Ice Sheet Contributions (+ or - ?) Current rate of ESLR = 0.15 cm yr -1

4. “Even if the ice melted, there would be no rise in ocean levels. After all, if you have a glass of water with ice cubes in it, as the ice melts, it simply turns to liquid and the water level in the glass remains the same.” (Rush Limbaugh)

6. Can coastal wetlands persist given predicted increases in the rate of ESLR?

7. Factors Affecting Wetland Elevation Relative to Sea Level O.M. Production (above and belowground) Allogenic Sediment Deposition Eustatic Sea Level Rise Deep Subsidence Shallow Subsidence (Primary Compaction and Decomposition)

8. Deltaic systems as models for future trends

9. Factors Affecting Wetland Elevation Relative to Sea Level O.M. Production (above and belowground) Allogenic Sediment Deposition Eustatic Sea Level Rise Deep Subsidence Shallow Subsidence (Primary Compaction and Decomposition)

10. modern delta(2500 - 800 yrs BP) (4000 -2000 yrs PB)

12. Factors Affecting Wetland Elevation Relative to Sea Level O.M. Production (above and belowground) Allogenic Sediment Deposition Eustatic Sea Level Rise Deep Subsidence Shallow Subsidence (Primary Compaction and Decomposition) Tide Gauge

14. Factors Affecting Wetland Elevation Relative to Sea Level O.M. Production (above and belowground) Allogenic Sediment Deposition Eustatic Sea Level Rise Deep Subsidence Shallow Subsidence (Primary Compaction and Decomposition) Horizon Markers

16. Factors Affecting Wetland Elevation Relative to Sea Level O.M. Production (above and belowground) Allogenic Sediment Deposition Eustatic Sea Level Rise Deep Subsidence Shallow Subsidence (Primary Compaction and Decomposition) SET and Horizon Markers

20. Old Oyster Bayou (1992 - 2000) O.M. Production Allogenic Sediment Deposition Eustatic Sea Level Rise……………. 0.15 cm/year Deep Subsidence…………………… 0.70 cm/year Shallow Subsidence………………… 0.12 cm/year 0.48 cm/year Elevation Deficit = 0.49 cm/year

21. Problems with Direct Measurements

23. Pulsing Events

24. Storm delivers 2 cm thick sediment layer 16,500 grams of mineral matter/m 2 1886 - 1998: 9 storms with winds over 100 mph Return rate of once every 12 years

25. Decomposition Primary Production Sediments Wetland Elevation

26. Decomposition Primary Production Sediments Wetland Elevation Feedback

27. A combined field and modeling approach

29. Some Recent Model Applications Effect of SLR on coastal wetlands in NW Mediterranean deltas The importance of pulsing event for maintaining wetland elevation relative to sea level Modeling sediment collapse in a Honduran mangrove forest following Hurricane Mitch The effect of wastewater effluent on sediment dynamics in coastal wetlands.

30. Eight Year Field Study in Old Oyster Bayou

31. Old Oyster Bayou (1992 - 2000) O.M. Production Allogenic Sediment Deposition Eustatic Sea Level Rise……………. 0.15 cm/year Deep Subsidence…………………… 0.70 cm/year Shallow Subsidence………………… 0.12 cm/year 0.48 cm/year Elevation Deficit = 0.49 cm/year

32. Elevation at Old Oyster Bayou (Relative to Sea-Level)

33. Britch and Dunbar (1996). Land Loss is coastal Louisiana

34. A. ESLR 15.6 cm/100 yrs D.S. = 0.35 cm/yr B. ESLR 15.6 cm/100 yrs D.S. = 0.7 cm/yr C. ESLR 48 cm/100 yrs D.S. = 0.35 cm/yr D. ESLR 48 cm/100 yrs D.S. = 0.7 cm/yr

35. 1886 - 1998: 9 storms with winds over 100 mph Return rate of once every 12 years

42. Ebro Delta Wetland Site Year

43. Ebro Delta Wetland

44. Chioggia Wetland: Po Delta, Italy

45. Some General Conclusions Few site could keep pace with predicted increases in ESLR. Maintenance or restoration of pulsing functions are critical. Wetland elevation is most sensitive to rates of deep subsidence, a forcing function in the model, mineral inputs, and below ground production. Wetland elevation was least sensitive to rates of decomposition. Action before the “point of no return” due to positive feedback loops.

46. Future Directions More mechanistic algorithms to describe below ground processes, soil compaction, and mineral inputs. Spatilization and links to hydrodynamic models Develop better links between elevation and primary production

47. Pore Volume (%) Total weight above core cohort (g) 100% 50% 75% 0 2010 k Maximum Reduction Maximum Reduction/2 Minimum Reduction compaction i = total weight i /(k + total weight i )