The purpose of this project was to monitor the recovery of marsh vegetation following Hurricane Katrina in the Breton Sound estuary, which is directly influenced by the Caernarvon freshwater diversion. From March 2006 until October 2007, we measured above- and belowground biomass, soil porewater nutrients (NOx, NH4, and PO4), porewater salinity, porewater sulfide concentrations, and soil redox potential bimonthly at duplicate Near (N), Intermediate (M), and Far (F) sites (with respect to the diversion), as well as at a Reference (C) site. End of season live (EOSL) below and above ground biomass was measured at 26 separate stations where vegetation studies had been done previously. Peak standing crop ranged from 423 g/m2/yr at site M2 to 1515 g/m2/yr at F1. Aboveground biomass was significantly greater at N1 than at N2, M1, or M2. Peak belowground biomass ranged from 8315 g/m2/yr at C2 to 17890 g/m2/yr at N1. Multiple regression analysis showed that sulfide levels were related to the amount of belowground biomass (p < 0.05; R2=0.13). PO4 concentration was related to the amount of aboveground biomass (p<0.05; R2=0.09). Short term vertical marsh accretion measurements ranged from 0.49 cm y-1 at N2 to 1.25 cm y-1 at N1, suggesting that all the study sites are stable or accreting at a rate which offsets local RSLR. Analysis of the results of short term accretion compared to regional relative sea level rise (RSLR) indicates that all Caernarvon sites are keeping pace with RSLR. Analysis of porewater parameters showed that stress on plants was low to moderate while nutrient concentrations were greatest at the Near sites.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06102008-194156 |
| Date | 11 June 2008 |
| Creators | Moerschbaecher, Matthew Korbel |
| Contributors | White, John R., Wascom, Mike, Wilson, Vince, Day, John W. |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06102008-194156/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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