Abstract Most terrestrial organic matter (OM) is released from clay surfaces when the clay-OM complex enters saline ocean margins and is replaced with ocean OM. However, it remains uncertain how salinity would affect the decoupling of adsorbed OM on clay surfaces. Here we show that the specific location of OM on clay mineral surfaces made a difference on OM migration. The OM trapped on the outer surface of the clay was further consolidated in the presence of salinity, while the OM in the interlayer was exchanged with sodium ions and desorbed. The desorbed OM was further analyzed by Raman spectroscopy and three-dimensional excitation emission matrix fluorescence spectroscopy, which analyses revealed that the aromatic protein, fulvic acid-like organics, microbial byproduct, and humic acid-like substances were likely to adsorb on the clay surface under saline conditions. These results indicated that the clay-terrestrial OM association is strong in saline estuaries, with the terrestrial OM unlikely to break away from clay surfaces.

中文翻译：

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存在盐分时从粘土表面解偶联的有机物质的定量评估

摘要 当粘土-有机质复合物进入咸洋边缘并被海洋有机质取代时，大部分陆地有机质（OM）是从粘土表面释放出来的。然而，仍不确定盐度将如何影响粘土表面吸附的 OM 的解耦。在这里，我们表明粘土矿物表面上 OM 的特定位置对 OM 迁移产生了影响。困在粘土外表面的有机质在盐度存在下进一步固结，而夹层中的有机质与钠离子交换并解吸。解吸的 OM 进一步通过拉曼光谱和三维激发发射矩阵荧光光谱分析，分析表明芳香蛋白、类富里酸有机物、微生物副产物、在盐分条件下，腐殖酸类物质很可能吸附在粘土表面。这些结果表明，在咸水河口，粘土-陆地 OM 关联性很强，陆地 OM 不太可能脱离粘土表面。