Dissolved organic matter (DOM) is widespread in natural water bodies and plays an essential role in ecological processes of aquatic ecosystems. However, spatial variability of DOM in shallow lakes is still kept unclear. Surface water, overlaying water and sediment samples were collected at 61 sampling sites in the whole Baiyangdian Lake to investigate spatial variability and distribution patterns of organic matter contents in three environmental compartments using geostatistical analysis. Results showed that organic matter (OM) contents in sediments were higher with medium variability, and lower DOM content occurred in surface water, with medium variability in overlying waters and high variability in surface waters. The highest DOM contents in waters and OM in sediments appeared in Zaolinzhung (ZLZ) and Zaozhadian (ZZD), respectively, while a relatively low contents appeared in ZLZ sediments. DOM in surface water and overlying water were negatively correlated with OM in sediments. Semi-variance functions showed that a strong spatial autocorrelation for DOM in waters, while OM in sediments had a medium spatial correlation. The autocorrelation distance of DOM in waters was between 1.16 km and 11.70 km, and OM in sediments was 4.25 km. The findings of this work can contribute to better understanding spatial variability of OM, which would provide a guidance for the sampling optimization of waters and sediments in the Baiyangdian Lake and lake sustainable management.

中文翻译：

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白洋淀水沙系统溶解有机质的空间变异


溶解有机物（DOM）广泛存在于自然水体中，在水生生态系统的生态过程中发挥着重要作用。然而，浅水湖泊 DOM 的空间变异仍不清楚。在整个白洋淀的61个采样点采集了地表水、上覆水和沉积物样品，利用地统计分析研究了三个环境区划有机质含量的空间变异和分布格局。结果表明，沉积物中有机质（OM）含量较高，且地表水体有机质含量较低，上覆水体有机质含量较高，地表水体有机质含量较高。水体中 DOM 含量最高，沉积物中 OM 含量最高，分别出现在枣林中 (ZLZ) 和枣扎店 (ZZD)，而 ZLZ 沉积物中含量相对较低。地表水和上覆水体中的 DOM 与沉积物中的 OM 呈负相关。半方差函数表明，水域中的 DOM 具有较强的空间自相关性，而沉积物中的 OM 具有中等的空间相关性。水域中DOM的自相关距离在1.16~11.70 km之间，沉积物中OM的自相关距离为4.25 km。这项工作的结果有助于更好地了解有机质的空间变异性，为白洋淀水体和沉积物的采样优化以及湖泊可持续管理提供指导。