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Freshwater restoration of tidal swamps: lessons from remediation during the Deepwater Horizon Incident
Dr. Beth A. Middleton U.S. Geological Survey, National Wetlands Research Center, LA
Deepwater Horizon Drilling Rig Drilling 1500 m below surface
Fire, April 20, 2010 Plugged, September 20
Hydrologic remediation effort begun…
Wikipedia, 2010 Wikipedia, 2010
Are there any lessons for restoration?
Mississippi River – 2010 water release to Jean Lafitte NHP&P (PT-ECP; CRMS)
1 2 3 km N
May 2010 sign test p<0.0001 water level > salinity level <
Davis Pond Release Jean Lafitte NHP&P
*normal operation=Sep 2010
ns
-
+
+
- +
water salinity
Davis Pond CRMS 0188 CRMS 0234
Deepwater Horizon Incident: natural experiment LA coast sinking. Vegetation response to 6x water?
Are swamps resilient after water/salinity changes? elevation, production, decomposition
SET - Sediment Elevation Table
Roberts/Middleton NSF RAPID DEB-1049838
Jean Lafitte NP
Big Thicket NP St Marks NWR
Roberts/Middleton NSF RAPID DEB-1049838
NABSCN sites NABSCN-RAPID
Annual Production
dendrometer tree growth
root ingrowth
leaf litter
2010 = good year for trees? Middleton/Johnson/Roberts – in review
root production↑ litter production↑
baldcypress: higher growth in lower salinity
North American Baldcypress Swamp Network
Regime shift: elevation increase with remediation?
before remediation
after remediation
piecewise linear regression F = 30.1, p < 0.0001
Model SS df F p
X11 2578.6 1 45.6 <0.0001
X22 699.5 1 12.6 0.0005
X33 716.6 1 12.9 0.0004
Error 5012.5 12 30.2 <0.0001
Elevation change at SETs, 2007-10 vs. 2011, Jean Lafitte NHP&P Piecewise regression model output using second order polynomials. Linear regression model lack of fit: SS = 6082.3, F = 17.5, p < 0.0001.
LA 2011: less decomposition at >10 cm depth after remediation
LA 2011: > wood decomposition faster after remediation
Decomposition and hydrologic remediation
Resilience hypothesis: coastal building with more freshwater? *production ? *decomposition ? *elevation ?
Lessons – freshwater remediation increases -above ground production -elevation
Hydrologic remediation – good for coasts? dying Texas wetland trees: high salinity, water abstraction
fresh water release?
Dying trees atypical needle drop resprouting needles peeling bark dead tree 2012 Texas survey
dead tree survey, drought, 2012 > 20 m tall: 7.7% ~ 10-20 m tall: 50.0% < 10 m tall: 81.3%
Texas tidal freshwater swamp (high salinity: 4–6 ppt)
Deepwater Horizon Drilling Rig Drilling 1500 m below surface
Fire, April 20, 2010 Plugged, September 20
Lesson: freshwater remediation reduces coastal salinity
Wikipedia, 2010 Wikipedia, 2010
Justin Stelly
Guodong Wang
Thanks: USGS, National Science Foundation DEB1049838 RAPID, ESA Seeds, Japanese/Korean/Turkish/Chinese Academies of Science
Lei Ting
Serge Farinas
Mel McCollough
Inyoung Jang
Matt Ripley
Onur Turker
Sam Primer
Evelyn Anemaet.
Swamp Resilience & Hydrologic Remediation -decomposition/production/denitrification higher in low salinity -balance of processes related to elevation -can higher production offset losses?
absolute elevation Trimble RTK unit
tree stress & water release: remote sensing photosynthesis
DOI & State Land Owners Cypress Creek NWR & IDNR IL Reelfoot Lake & Lake Isom NWR TN White River NWR AR Morgan Brake & Hillside NWR MS Tensas NWR LA Cat Island NWR LA Big Thicket NHP&P TX Jean Lafitte NHP&P LA St Marks NWR Big Bend/Aucilla WMA FL
Importance to coastal management...
AVIRIS
Abnormal drought in 2012? Restoration -genetics of live vs. dying cypress – Tachida/Middleton Strategic water release to combat rising coastal salinity, water abstraction?
Lake Bayou, Texas
Freshwater from Mississippi diversion pushed oil offshore. Downstream wetlands had lower salinity. Hydrologic remediation useful for wetland management.
Future coastal sea level rise & drought – salinity increase *freshwater wetland may shift to brackish and salt marshes
pore water salinity
elevation
IPCC 2012
Thanks U.S. Geological Survey National Science Foundation
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