Effects of soil ageing on the accumulation of hydrogen sulphide and metallic sulphides in mangrove areas in Singapore

Abstract

The effects of soil ageing on the accumulation of hydrogen sulphide and metallic sulphides were studied in reclaimed mangrove plots of increasing ages. The analysis was carried out using a low-cost electrochemical approach, utilizing a sulphide volatilization/trapping procedure followed by sulphide quantification with an ion-selective electrode technique. The results showed that the content of hydrogen sulphide in the soil increased with age. Initially, the content of metallic sulphides also increased with the age of the soil. However, once the supply of metallic soil components for sulphide precipitation had been exhausted, the sulphides generated in the soils existed as hydrogen sulphide. The reasons for these patterns of sulphide accumulation in the mangrove soil and their possible impact on the growth of different types of mangrove vegetation are briefly discussed.