Sulfur enrichment of humic substances in a Delaware salt marsh sediment core

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(91)90156-Y· OSTI ID:5600078

Ferdelman, T G; Church, T M; Luther, G W ^[1]

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1. Univ. of Delaware, Newark (USA)

Humic sulfur, operationally defined as the sulfur extracted with humic substances in 0.1 N NaOH solution, comprises up to 51{percent} of the total sulfur inventory in a sediment core taken from a Delaware Spartina alterniflora marsh. Pyrite sulfur is the next largest fraction, except at the near-surface sediments, where zerovalent sulfur concentrations are significant. X-ray photoelectron spectroscopy indicates that the humic sulfur consists of sulfoxides or sulfones and, in a more reduced state, organic sulfides and/or organic polysulfides. A subsurface decrease in the humic acid C:S atomic ratio to 56 {plus minus} 2 suggests that the upper 4 cm of marsh sediment is the locus for humic sulfur formation. S. alterniflora detritus and microbial biomass cannot fully account for observed sulfur enrichment of humic C:S atomic ratios. Therefore, the enrichment of humic substances by sulfur is probably via reaction of reduced sulfur compounds with organic matter. A humic sulfur formation rate of 10.6 {mu}mol S {center dot} cm{sup {minus}3} {center dot} a{sup {minus}1} is calculated for the surface sediments and leads to an areal production of 18 {mu}mol S {center dot} cm{sup {minus}2} {center dot} a{sup {minus}1} of humic sulfur. Humic sulfur formation and preservation is enhanced by the limited availability of iron for the rapid precipitation of iron sulfide minerals and the apparent resistance of organic sulfur compounds towards reoxidation to sulfate, especially in the upper 9 cm of marsh sediment where inorganic sulfur compounds are rapidly oxidized.

• OSTI ID: 5600078
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 55:4; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
HUMUS
SULFUR CONTENT
SEDIMENTARY ROCKS
DIAGENESIS
GEOLOGIC HISTORY
SEDIMENTS
CHEMICAL COMPOSITION
DELAWARE
DRILL CORES
ENRICHMENT
GEOCHEMISTRY
MARSHES
PHASE STUDIES
PYRITE
SULFUR
X-RAY SPECTROSCOPY
AQUATIC ECOSYSTEMS
CHALCOGENIDES
CHEMISTRY
DEVELOPED COUNTRIES
ECOSYSTEMS
ELEMENTS
FEDERAL REGION III
IRON COMPOUNDS
IRON SULFIDES
MINERALS
NONMETALS
NORTH AMERICA
ROCKS
SPECTROSCOPY
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
WETLANDS
580000* - Geosciences