Quick sulfide buffering in inner shelf sediments of the East China Sea impacted by eutrophication

• Published in: Environmental earth sciences Vol. 71; no. 1; pp. 465 - 473
• Main Authors: Liu, Juan, Zhu, Mao-Xu, Yang, Gui-Peng, Shi, Xiao-Ning, Yang, Ru-Jun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2014; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Algae; Algal blooms; Biogeosciences; Coastal zone; coasts; continental shelf; Continental shelves; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; East China Sea; ecosystems; Engineering and environment geology. Geothermics; Environmental Science and Engineering; Eutrophication; Exact sciences and technology; Geochemistry; Geology; Hydrology/Water Resources; iron; Marine and continental quaternary; Marine ecology; Organic matter; Original Article; oxides; Pollution, environment geology; Protected areas; Pyrite; Sediments; Sulfate reduction; Sulfides; Surficial geology; Terrestrial Pollution; Water management; East China Sea; West Pacific; Pacific Ocean; INW, Donghai Sea; Sulfide; Labile Fe; Marine sediments; Buffering capacity; East China Sea; Eutrophication; inner shelf; continental shelf; iron sulfides; oxides; accumulation; eutrophication; buffers; ferrous iron; sulfates; pyrite; acids; chemical reduction; ecosystems; organic materials; iron; marine sediments; volatiles; sulfides
• DOI: 10.1007/s12665-013-2454-4
• ISSN: 1866-6280

In the eutrophic coastal ocean, quick formation of iron (Fe) sulfide is environmentally important to effectively prevent accumulation of dissolved sulfide and its detrimental effects on the benthic ecosystem. In this study, 0.5 N HCl-extractable labile Fe (LFe), acid volatile sulfide, and pyrite in the East China Sea inner shelf sediments were examined to investigate the mechanisms of quick sequestration of dissolved sulfide and potential impacts of frequent algal blooms on the capacity of quick sulfide-buffering in eutrophic coastal areas of the large-sized continental shelf subject to massive terrestrial input. The results indicate that sulfate reduction has been competitively suppressed by dissimilatory Fe reduction due to limited availability of labile organic matter. Dissolved sulfide can be quickly buffered by reaction with LFe and, therefore, is difficult to accumulate to a high level. The quick sulfide-buffering capacity has not become exhausted partly because of the formation of un-sulfidized LFe(II) via dissimilatory reduction of less reactive Fe oxides. It is expected that dissolved sulfide will not pose detrimental effects on the benthic ecosystem in the near future if the current biogeochemical/ecological state remains.