Chemical and spectroscopic characterization of dissolved humic substances in a mangrove-fringed estuary in the eastern coast of Hainan Island, China

• Published in: Chinese journal of oceanology and limnology 2013-03, Vol.31 (2), p.454-463
• Main Author: 张耀玲 杜金洲 彭浡 张芬芬 赵欣 张经
• Format: Article
• Language: English
• Subjects: Aliphatic compounds; Aromatic compounds; Biogeochemistry; Brackish; Brackishwater environment; Carbohydrates; Carbon-nitrogen ratio; Chemical analysis; Coastal zone; Dissolved organic matter; Earth and Environmental Science; Earth Sciences; Estuaries; Estuarine dynamics; Forests; Fulvic acids; Humic acids; Humic substances; Mangroves; Marine; NMR; Nuclear magnetic resonance; Oceanography; Oxidation; Photooxidation; Pore water; Resins; Seawater; Water analysis; Water sampling; 东部沿海; 中国海南岛; 光谱特性; 河口; 溶解有机物; 环绕; 红树林; 腐殖物质
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-013-2138-7

Mangrove-derived dissolved organic matter （DOM） has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fringed estuarine and coastal areas, dissolved humic substances （DHS） were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island, South China. Fulvic acids, humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-g and XAD-4 resins. Chemica~ and spectroscopic methods were used to analyze the features of these DHS. Compared to the mangrove pore-water DHS, the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates, but less aromatic structures and carboxyl groups. As for the three fractions of the two DHS, XAD-4 fractions contain more aliphatics, carbohydrates, carboxyl groups, and enrich in 13C with respect to both fulvic and humic acids. Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.