Abstract
Acid-decomposable organic carbon, proteins, carbohydrates, and lipids were analyzed to identify the organic substances in tideland sediment. Proteins, carbohydrates and lipids were analyzed as amino acids, sugars and fatty acids, respectively, after acid hydrolysis. The following results were obtained from the analyses of the sediments in three tidelands of the Ariake Sea and two tidelands of Hakata Bay.
(1) The percentage of acid-decomposable organic carbon decreased from 47.9% at a 0-10cm depth to 29.9% at a 100-110cm depth in the analysis of sediments in the Ariake tideland; however, the total organic carbon did not change significantly. This result shows that most organic substances were not decomposed to carbon dioxide or methane, but changed to humic acid and kerogen under anaerobic conditions.
(2) The percentage of acid-decomposable organic carbon in sediments (0-10cm) of the Wajiro tideland under aerobic conditions was as high as 48.6%, however, that of the Imazu tideland under anaerobic conditions was as low as 27.5%.
(3) The relative concentrations of amino acids and sugars were almost the same for all sediments; therefore, the protein and carbohydrate structures in the tideland sediments were considered to be similar.
