Abstract Characterization of the sedimentary organic matter (SOM) within an intermittently open coastal lagoon in SE Uruguay was carried out using optical properties of dissolved organic matter (DOM), stable isotope analyses (δ13C and δ15N) and mineralogical properties of the sedimentary pool were assessed using Fourier transform infrared spectroscopy (FTIR). Additionally, chemical and biological variables including total and dissolved nitrogen and phosphorus, chlorophyll-a in water and sediments, and benthic diatoms were analyzed. Potential sources of SOM (e.g., marine and riverine phytoplankton, terrestrial plant material) and fauna were collected during summer, autumn, and winter from seaward (South) to landward (North) zones. In the pore water, the high contribution of fluorescent, protein-like components, the δ13C values of sediments (−22‰ to −16‰), and the low C/N ratios of sediments (∼7), indicate the dominant source of SOM is marine microalgae (benthic/planktonic, tychoplanktonic). Most of the diatom species recorded in the sediments were benthic marine/brackish species including the polyhaline species Pseudopodosira echinus. Furthermore, FTIR spectra showed higher contributions of quartz, carbonates, and feldspar towards the seaward zones. Clay minerals increase towards landward zones, indicating changes in the hydrodynamic energy within the lagoon with greater overall rates of sediment deposition in landward zones. In shallow systems, active resuspension and mixing conditions may help to explain spatial similarities in the composition of the sedimentary pool. The combined use of stable isotopes, FTIR, diatoms and nutrient measurements (rather than single approaches) represents an alternative comprehensive tool to infer information on the composition and sources contributing to the sedimentary pool.

中文翻译：

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沉积池中的本土有机碳贡献：Laguna Garzón 的多分析方法

摘要 利用溶解有机质 (DOM) 的光学特性、稳定同位素分析 (δ13C 和 δ15N) 和沉积池的矿物学特性，对乌拉圭东南部间歇性开放沿海泻湖内的沉积有机质 (SOM) 进行了表征。使用傅里叶变换红外光谱 (FTIR)。此外，还分析了化学和生物变量，包括总和溶解的氮和磷、水和沉积物中的叶绿素 a 以及底栖硅藻。SOM 的潜在来源（例如，海洋和河流浮游植物、陆生植物材料）和动物群是在夏季、秋季和冬季从向海（南部）到向陆（北部）区域收集的。在孔隙水中，荧光、蛋白质样成分的高贡献，沉积物的δ13C值（-22‰至-16‰）和沉积物的低C/N比（~7）表明SOM的主要来源是海洋微藻（底栖/浮游、浮游）。沉积物中记录的大多数硅藻物种是底栖海洋/微咸物种，包括多卤物种 Pseudopodosira echinus。此外，FTIR 光谱显示石英、碳酸盐和长石对海区的贡献更大。粘土矿物向陆地区域增加，表明泻湖内的水动力能量发生变化，陆地区域的沉积物总体沉积速率更大。在浅层系统中，活跃的再悬浮和混合条件可能有助于解释沉积池组成的空间相似性。稳定同位素、FTIR、