Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients
Spartina alterniflora is a salt marsh macrophyte found from Canada to the Gulf of Mexico which often provides the dominant plant cover. Although S. alterniflora is well known for its high aboveground productivity, fifty to ninety percent of the total plant production occurs belowground. No previous...
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ndltd-LSU-oai-etd.lsu.edu-etd-11142006-1253082013-01-07T22:50:51Z Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients Darby, Faith Armand Oceanography & Coastal Sciences Spartina alterniflora is a salt marsh macrophyte found from Canada to the Gulf of Mexico which often provides the dominant plant cover. Although S. alterniflora is well known for its high aboveground productivity, fifty to ninety percent of the total plant production occurs belowground. No previous studies address the seasonal variation of belowground biomass or the response of above-and belowground biomass to nutrients at the southern limits of its U. S. range. The objectives of this study were to: 1) document the seasonal variability of its above- and belowground biomass and test for responses to various combinations of N, P, and Fe supplements, 2) test the usefulness and variability of three functional indicators of nutrient use efficiency, resorption efficiency, resorption proficiency, and, 3) compare nutrient limitation controls in East coast and Gulf of Mexico salt marshes. Various combinations of N additions resulted in more aboveground biomass, higher stem densities and longer stem lengths, but had no effect on the amount of belowground biomass. No change in the aboveground biomass observed when P was added, but there was a decrease in the live belowground biomass. The average N : P molar ratios in the above- and belowground tissues, and three resorption indices supported the hypothesis that the accumulation of biomass aboveground was limited by N, and by P belowground. Higher soil respiration and a lower Eh are anticipated additional soil property changes with nutrient enrichment. The observations from these field trials formed a unified conclusion, which is that the widespread effects of coastal eutrophication leads to lower root and rhizome biomass, belowground production, and organic matter accumulation. The cumulative effects of increased nutrient loadings to salt marshes may be to decrease soil elevation and accelerate the conversion of emergent plant habitat to open water, particularly at the lower elevation range of the plant. These results support management actions supporting coastal marsh conservation through: 1) reducing nutrient loading to coastal zones and not diverting more nutrients to coastal marshes, 2) solving water quality problems with a multiple nutrient approach, and, 3) choosing monitoring metrics based on both belowground and aboveground plant production. R. Eugene Turner Billy James Williams Jaye Cable Robert Gambrell Vincent Wilson LSU 2006-11-15 text application/pdf http://etd.lsu.edu/docs/available/etd-11142006-125308/ http://etd.lsu.edu/docs/available/etd-11142006-125308/ en 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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Oceanography & Coastal Sciences Darby, Faith Armand Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
description |
Spartina alterniflora is a salt marsh macrophyte found from Canada to the Gulf of Mexico which often provides the dominant plant cover. Although S. alterniflora is well known for its high aboveground productivity, fifty to ninety percent of the total plant production occurs belowground. No previous studies address the seasonal variation of belowground biomass or the response of above-and belowground biomass to nutrients at the southern limits of its U. S. range. The objectives of this study were to: 1) document the seasonal variability of its above- and belowground biomass and test for responses to various combinations of N, P, and Fe supplements, 2) test the usefulness and variability of three functional indicators of nutrient use efficiency, resorption efficiency, resorption proficiency, and, 3) compare nutrient limitation controls in East coast and Gulf of Mexico salt marshes.
Various combinations of N additions resulted in more aboveground biomass, higher stem densities and longer stem lengths, but had no effect on the amount of belowground biomass. No change in the aboveground biomass observed when P was added, but there was a decrease in the live belowground biomass. The average N : P molar ratios in the above- and belowground tissues, and three resorption indices supported the hypothesis that the accumulation of biomass aboveground was limited by N, and by P belowground. Higher soil respiration and a lower Eh are anticipated additional soil property changes with nutrient enrichment.
The observations from these field trials formed a unified conclusion, which is that the widespread effects of coastal eutrophication leads to lower root and rhizome biomass, belowground production, and organic matter accumulation. The cumulative effects of increased nutrient loadings to salt marshes may be to decrease soil elevation and accelerate the conversion of emergent plant habitat to open water, particularly at the lower elevation range of the plant. These results support management actions supporting coastal marsh conservation through: 1) reducing nutrient loading to coastal zones and not diverting more nutrients to coastal marshes, 2) solving water quality problems with a multiple nutrient approach, and, 3) choosing monitoring metrics based on both belowground and aboveground plant production. |
author2 |
R. Eugene Turner |
author_facet |
R. Eugene Turner Darby, Faith Armand |
author |
Darby, Faith Armand |
author_sort |
Darby, Faith Armand |
title |
Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
title_short |
Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
title_full |
Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
title_fullStr |
Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
title_full_unstemmed |
Belowground Biomass of Spartina alterniflora: Seasonal Variability and Response to Nutrients |
title_sort |
belowground biomass of spartina alterniflora: seasonal variability and response to nutrients |
publisher |
LSU |
publishDate |
2006 |
url |
http://etd.lsu.edu/docs/available/etd-11142006-125308/ |
work_keys_str_mv |
AT darbyfaitharmand belowgroundbiomassofspartinaalternifloraseasonalvariabilityandresponsetonutrients |
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