Spatial dependence of reduced sulfur in Everglades dissolved organic matter controlled by sulfate enrichment

Environmental Science & Technology
By: , and 

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Abstract

Sulfate inputs to the Florida Everglades stimulate sulfidic conditions in freshwater wetland sediments that affect ecological and biogeochemical processes. An unexplored implication of sulfate enrichment is alteration of the content and speciation of sulfur in dissolved organic matter (DOM), which influences the reactivity of DOM with trace metals. Here, we describe the vertical and lateral spatial dependence of sulfur chemistry in the hydrophobic organic acid fraction of DOM from unimpacted and sulfate-impacted Everglades wetlands using X-ray absorption spectroscopy and ultrahigh-resolution mass spectrometry. Spatial variation in DOM sulfur content and speciation reflects the degree of sulfate enrichment and resulting sulfide concentrations in sediment pore waters. Sulfur is incorporated into DOM predominantly as highly reduced species in sulfidic pore waters. Sulfur-enriched DOM in sediment pore waters exchanges with overlying surface waters and the sulfur likely undergoes oxidative transformations in the water column. Across all wetland sites and depths, the total sulfur content of DOM correlated with the relative abundance of highly reduced sulfur functionality. The results identify sulfate input as a primary determinant on DOM sulfur chemistry to be considered in the context of wetland restoration and sulfur and trace metal cycling.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Spatial dependence of reduced sulfur in Everglades dissolved organic matter controlled by sulfate enrichment
Series title Environmental Science & Technology
DOI 10.1021/acs.est.6b04142
Volume 51
Issue 7
Year Published 2017
Language English
Publisher American Chemical Society
Publisher location Washington, D.C.
Contributing office(s) National Research Program - Central Branch
Description 10 p.
First page 3630
Last page 3639
Country United States
State Florida
Other Geospatial Everglades National Park