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Distributions of sulfur forms and sulfate-reducing bacteria in yellow soil of small karst catchment.

ZHANG Wei1,2*, ZHANG Li-li2,3#br#   

  1. (1 School of Geography and Tourism, Guizhou Normal College, Guiyang 550018, China; 2 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China).
  • Online:2016-10-10 Published:2016-10-10

Abstract: We analyzed the contents of total sulfur (S), SO42-S, total reduced inorganic sulfur (TRIS), organic S, and sulfatereducing bacteria (SRB) groups and quantities in yellow soil to examine the distribution patterns of sulfur forms and SRBs in soils under acid deposition in the karst areas of Southwest China. The results showed that organic sulfur was the major sulfur form, and SO42- was the major inorganic sulfur form in yellow soil. DesulfovibrioDesulfomicrobium was detected at different soil depths, indicating that DesulfovibrioDesulfomicrobium is the dominant SRB group in yellow soil. The soil depths of increasing SRB quantity and TRIS contents corresponded well to the depths of decreasing SO42--S contents, indicating that dissimilatory SO42- reduction occurred in yellow soil with TRIS as the main product. The residual SO42- after biological S retention was firstly adsorbed and then desorbed; desorbed SO42- could transport downward and was subsequently re-adsorbed and accumulated in deep soil layers. This explained the increasing SO42-S contents in bottom layers of yellow soil profiles. The deposited SO42- was retained as organic sulfur and adsorbed SO42- in yellow soil, then yellow soil may release more S into rivers by organic sulfur mineralization and desorption of the adsorbed SO42- in a long period after a large decrease in annual sulfur deposition rate. Therefore, the environmental implications such as changes of soil properties and chemical compositions of river water in southwest China should be investigated in the future.

Key words: nutritional substance, protective enzyme, Frankliniella occidentalis., secondary substance, detoxification enzyme