Early Flotant Establishment and Growth Dynamics in a Nutrient Amended Wetland in the Lower Missisippi River Delta
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 ?15N ratios varied significantly (P <0.05) along a 75m marsh transect while mean ?13C 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 ?15N of H. umbellata was less enriched at 0-75 m (9.69 ± 1.9) compared to 100-200 m (20.99 ± 3.8). The ?13C 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 ?15N enrichment across the 75 m transect. Nutrient availability affected NAPP and ?15N. 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.
Advisor:Charles E. Sasser; Richard Keim; John W. Day, Jr.
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:oceanography coastal sciences
Date of Publication:11/12/2007