Date of Award

Fall 2010

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Vladislav Gulis

Second Advisor

John J. Hutchens, Jr.

Third Advisor

Eric T. Koepfler

Additional Advisors

Keith R. Walters

Abstract

Spartina wrack has not been studied extensively despite considerable accumulation of material in salt marshes. This study addressed: (1) decomposition rates of Spartina alterniflora wrack along a salt marsh elevational gradient; (2) the relative importance of fungi vs. bacteria on Spartina wrack; (3) differences in fungal assemblage structure between standing-dead Spartina and Spartina wrack. Four sites in the salt marsh at Baruch Marine Field Lab in North Inlet, SC were used. Each site had 4 sampling stations (zones) along the elevational gradient: subtidal, intertidal, high-marsh and terrestrial. Decomposition rates of Spartina in litterbags, associated microbial respiration, fungal and bacterial biomass (from ergosterol and epifluorescence microscopy, respectively) were followed over ten months (March-December 2009). Fungal assemblage structure was assessed by denaturing gradient gel electrophoresis (DGGE) of amplified ITS rDNA. We found a decrease of wrack decomposition rate along the elevational gradient (from low to high marsh) and considerably higher fungal than bacterial biomass in all zones. Fungal assemblages on Spartina wrack were surprisingly diverse, with more than 20 phylotypes per sample routinely detected. We observed a clear successional pattern in fungal assemblages as Spartina detritus transitioned from the standing dead position to wrack in all elevation zones. Overall, it appears that fungi are the major microbial decomposers of Spartina in salt marshes both in the standing dead position and as wrack.

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