Identifier

etd-11082007-155709

Degree

Master of Science (MS)

Department

Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

Nutrient dynamics and seasonal marsh growth were examined in a newly formed Panicum virgatum floating marsh at Thibodaux LA. The floating marsh formed in a cleared area of forested wetland receiving secondarily treated effluent. Net Areal Primary Productivity (NAPP), total belowground biomass, NO3, and δ15N ratios varied significantly (P <0.05) along a 75m marsh transect while mean δ13C varied between plant species. The upland end of the transect had the highest NAPP (3876 g m-2y-1), total belowground biomass (4079.0 ± 298.5 g m-2), and mean NO3 (5.4 ± 2.9 mg l-1). The mean floating-marsh δ15N of H. umbellata was less enriched at 0-75 m (9.69 ± 1.9‰) compared to 100-200 m (20.99 ± 3.8‰). The δ13C of the belowground peat mat of the floating marsh was similar to P. virgatum but not H. umbellata, indicating that P. virgatum was forming the mat. There was a significant decrease in NAPP, total belowground biomass, NO3 and δ15N enrichment across the 75 m transect. Nutrient availability affected NAPP and δ15N. Floating marsh NAPP in the 0-45 m was greater than most reported values for floating marsh. These results suggest that nutreint rich freshwater can promote restoration of floating marshes.

Date

2007

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

John W. Day, Jr.

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