Forms of Sulfur in Louisiana Marsh Soil

The amounts and profile distribution of various sulfur forms in Louisiana coastal marshes are important in understanding sulfur cycling as related to the origin and type of tidal wetland marshes. Sulfur forms and distribution were determined in P. hemitomon freshwater marsh, a S. patens brackish marsh, and a S. alterniflora salt marsh along a salinity gradient in Barataria Basin, Louisiana. Soil samples were fractionated into acid volatile sulfur (AVS), elemental sulfur, HCl-soluble sulfur, pyrite sulfur, ester sulfate sulfur, carbon-bonded sulfur, and total sulfur (see Chapter 11 for details). 

In Louisiana, extending along a salinity gradient from the Gulf of Mexico, organic S in the forms of ester sulfate S and C-bonded S is the predominant form of all marsh types representing 

76-87% of the total S present in fresh, brackish, and salt marshes (Krairapanond et al., 1992). The contribution of inorganic S to the total S pool was greater in salt marsh (24%) than in brackish (13%) and freshwater (22%) marshes. HCl-soluble S was a major component of the inorganic S fraction. Pyrite S comprised 3% of the total S present in individual marsh site (Table 18.10). 

Note Any two values having a common letter are not significantly different at the 5% level of significance on the basis of Duncan s Multiple Range Test (DMRT). 

Rates of S Accumulation in the Barataria Basin Tidal Marsh Soils (mean + SE, n = 15) Sedi- 

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