Charoenpong et al. 2026

The various nitrogen fractions in surface sediments from the inner Gulf of Thailand (GoT) during the rainy and dry seasons were analyzed to characterize the spatial and seasonal distribution of nitrogen fractions and evaluate their mobilization potential in the marine sediments. The average total nitrogen content (1419 +/- 653 mg/kg dry weight) in the inner GoT sediments was higher than those reported for other regions, suggesting that the nitrogen accumulation within the bay might be a greater concern than previously expected. Nitrogen in the inner GoT sediments was dominated by nontransferable fraction (73.6%), followed by strong oxidant extractable fraction (12.1%), weak acid extractable fraction (7.6%), strong alkali extractable fraction (3.9%), and ion-exchangeable fraction (2.8%), indicating that the sediments act as a final sink of nitrogen. However, the sediments in the northwestern and outer zones showed greater potential for nitrogen mobilization, reflecting a more prominent internal source of regenerated nitrogen from the sediment. This greatly increased our understanding of the geochemical behavior of nitrogen in tropical marine sediments within the Gulf of Thailand.

Reference: Charoenpong, C., Sangmanee, C., Zhan, L., Li, L., Liu, Y., Vasinamekhin, V., ... & Jiwarungrueangkul, T. (2026). Variations in geochemical forms and potential mobilization of nitrogen in marine sediments from a tropical eutrophic embayment: A case study of the inner Gulf of Thailand. Regional Studies in Marine Science, 105234.