This study explores biomarker composition in the sediment record from Lake Łebsko (LŁ) acting as a representative case of a coastal lake system. The broad context for the research was to provide insights into carbon cycling as well as the origin and transformations of organic C in this unique depositional environment over a long-term perspective. We studied 25 samples from a ca. 9 m long sediment sequence covering the entire Holocene. The samples were analysed with regard to inorganic (TIC, Fe/Mn, Mg/Ca, Al) and organic matter composition (TOC, hydrocarbons, hopanoids, n-alkanols, fatty acids, stanols, sterols etc.) as well as stable C and N isotopes. Our major finding was that the sedimentary organic matter (SOM) in the LŁ core was predominantly autochthonous albeit highly degraded. The degradation occurred during sedimentation in the water column and/or shortly after deposition and, based on earlier research of coastal lakes, it was related to high water turbulence and sediment mixing. We also found that: (i) higher plant biomarkers were overrepresented in the SOM, and (ii) bulk SOM indicators (e.g., TOC/N, δ¹³C_SOM, δ¹⁵N_SOM) provided more coherent paleoenvironmental information on the lake studied than hydrocarbon and n-alkanol biomarkers. From stable C isotope composition of SOM it emerged that changes in salinity affected the sources of C used for production of autochthonous SOM. During freshwater phases the production of the SOM was mainly fueled by CO₂ delivered from the lake catchment while during saltwater periods marine-derived bicarbonates were primarily used for photosynthesis.

这项研究探索了Łebsko湖（LŁ）的沉积物记录中的生物标志物组成，该湖是沿海湖泊系统的代表。这项研究的广泛背景是，从长远的角度来看，可以洞悉碳循环以及有机碳在这种独特沉积环境中的起源和转化。我们研究了约25个样本。9 m长的沉积序列覆盖了整个全新世。分析了样品的无机（TIC，Fe / Mn，Mg / Ca，Al）和有机物成分（TOC，碳氢化合物，类an烷，n-链烷醇，脂肪酸，甾烷醇，固醇等）以及稳定的C和N同位素。我们的主要发现是LŁ岩心中的沉积有机质（SOM）主要是自生的，尽管高度降解。退化发生在水柱中的沉积过程中和/或沉积后不久，并且根据沿海湖泊的早期研究，其退化与高水湍流和沉积物混合有关。我们还发现：（ⅰ）高等植物的生物标记物在SOM中过表现，以及（ii）散装SOM指示符（例如，TOC / N，δ ¹³ Ç _SOM，δ ¹⁵ Ñ _SOM）湖上提供了更多的相干古环境信息研究比碳氢化合物和n-链烷醇生物标志物。从SOM的稳定C同位素组成可以看出，盐度的变化影响了用于生产自生SOM的C的来源。在淡水阶段，SOM的生产主要由湖泊流域输送的CO ₂推动，而在盐水时期，海洋来源的碳酸氢盐主要用于光合作用。