n- Alkanes are biomarkers that are widely used as paleoenvironmental reconstruction proxies in lacustrine sediments. However, studies on their sedimentation and factors affecting sedimentation in large lakes remain relatively scarce. In this study, 120 surface sediments collected from Selin Co, central Tibetan Plateau, were used to analyze the spatial distribution of n -alkanes in a modern sedimentary system, and the factors controlling this distribution were further discussed. The sedimentary n- alkanes of Selin Co were mainly long- and middle-chain components with single or double peaks, belonging to the mixed-type input of terrestrial and aquatic plants. Leaf waxes derived from terrestrial plants in the catchment of Selin Co were the main source followed by aquatic plants, while planktonic algae living in the lake water column was a minor source, as demonstrated by their low concentration. The distribution of aquatic and terrigenous n- alkanes in the surface sediments showed a significant spatial heterogeneity; this was controlled by different factors and sedimentary processes. The distribution of terrigenous n- alkanes was mainly controlled by underwater topography; high concentrations in the sedimentary center of the east lake basin and the sub-basin in the northwest were evident. Aquatic n- alkanes were found in substantially higher concentrations in the western estuary of Zhagen River and Ali River, as well as in the southern sub-basin, Yagen Co. These distributions might be influenced by differences of geographical environment in the watershed of these main inflow rivers, as well as the intensity of sunlight, itself intensity controlled by the transparency of the water column. Although n- alkanes from the center of a lake could represent an integration of catchments in most cases, their spatial heterogeneity in large lakes like Selin Co would introduce uncertainty to paleoenvironmental reconstructions. Consequently, it is very important to investigate thoroughly the spatial distribution and controlling factors of n- alkanes in modern lake environments. It is inferred that these findings will have broad significance in large lakes similar to Selin Co, and that they will benefit studies that use n -alkanes as proxies to reconstruct past environmental changes.

中文翻译：

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青藏高原中部色林错湖表层沉积物中正构烷烃的空间分布

正构烷烃是广泛用作湖泊沉积物中古环境重建代理的生物标志物。然而，关于大湖沉积及其影响因素的研究相对较少。本研究利用从青藏高原中部色林错采集的120份表层沉积物分析了现代沉积体系中正构烷烃的空间分布，并进一步探讨了控制这种分布的因素。Selin Co沉积正构烷烃以长链和中链组分为主，具有单峰或双峰，属于陆生植物和水生植物的混合输入型。色林公司流域陆生植物叶蜡主要来源，其次是水生植物，而生活在湖水柱中的浮游藻类是次要来源，如它们的低浓度所示。表层沉积物中水生和陆源正构烷烃的分布具有显着的空间异质性；这是由不同的因素和沉积过程控制的。陆源正构烷烃的分布主要受水下地形控制；东部湖盆沉积中心和西北部亚盆地的高浓度分布明显。在扎根河和阿里河西部河口以及南部亚根流域发现水生正烷烃的浓度显着较高。这些分布可能受这些主要流域地理环境差异的影响。流入的河流，以及阳光的强度，本身的强度由水柱的透明度控制。尽管在大多数情况下来自湖中心的正烷烃可以代表集水区的整合，但它们在像 Selin Co 这样的大型湖泊中的空间异质性会给古环境重建带来不确定性。因此，深入研究现代湖泊环境中正构烷烃的空间分布及其控制因素非常重要。据推测，这些发现将在类似于Selin Co 的大型湖泊中具有广泛的意义，并且它们将有益于使用正构烷烃作为代理来重建过去环境变化的研究。它们在像 Selin Co 这样的大型湖泊中的空间异质性会给古环境重建带来不确定性。因此，深入研究现代湖泊环境中正构烷烃的空间分布及其控制因素非常重要。据推测，这些发现将在类似于Selin Co 的大型湖泊中具有广泛的意义，并且它们将有益于使用正构烷烃作为代理来重建过去环境变化的研究。它们在像 Selin Co 这样的大型湖泊中的空间异质性会给古环境重建带来不确定性。因此，深入研究现代湖泊环境中正构烷烃的空间分布及其控制因素非常重要。据推测，这些发现将在类似于Selin Co 的大型湖泊中具有广泛的意义，并且它们将有益于使用正构烷烃作为代理来重建过去环境变化的研究。