Lakes cover a global area that is about 35 times smaller than the oceans, but carbon burial in lakes and oceans are on the same order of magnitude. Hence, understanding the processes for such high organic carbon burial in lacustrine systems is essential. We applied proxies typically used for marine environments including amino acid (AA) content and their nitrogen stable isotope composition to the water columns and sediments of three lakes that differ in their trophic states and depositions rates of sedimentary terrestrial organic matter. Additionally, we used carbon isotope fingerprinting of AAs to characterise their sources and fates. We show that this set of proxies tracks sources and degradation processes in eutrophic lakes with high sedimentary total organic carbon and nitrogen content. Those lakes also have a high total hydrolysable amino acid (THAA) content as well as higher pigment concentrations. While the Chlorin degradation Index (CI) showed increasing values with depth, the patterns were less consistent for the Degradation Index (DI). In general, all parameters failed to describe degradation in the most oligotrophic lake due to the very low organic carbon and nitrogen content in the sediment. We show that AAs are mostly of autochthonous origin and that AA contribute 5–45% to the organic material in plankton, POM, and sediment. Proxies based on AA for bacterial reworking (ΣV) or trophic level (TL) showed increasing values in the water column but relatively stable values in the sediments. Furthermore, we show that methanotrophic bacteria led to increased values for the bacterial reworking proxy (ΣV) and extraordinarily low δ¹³C AA values (−30 to −60‰).

湖泊的全球面积大约是海洋的35倍，但湖泊和海洋中的碳埋藏量却在同一数量级上。因此，了解湖泊系统中如此高的有机碳埋藏过程至关重要。我们将通常用于海洋环境的代理（包括氨基酸（AA）含量及其氮稳定同位素组成）应用于营养状态和沉积陆生有机质沉积速率不同的三个湖泊的水柱和沉积物中。此外，我们使用了AA的碳同位素指纹图谱来表征其来源和命运。我们表明，这组代理跟踪具有高沉积总有机碳和氮含量的富营养化湖泊的来源和降解过程。这些湖泊还具有较高的总可水解氨基酸（THAA）含量以及较高的色素浓度。氯霉素降解指数（CI）随深度显示增加的值，而降解指数（DI）的模式则不一致。一般而言，由于沉积物中有机碳和氮的含量非常低，所有参数都无法描述最贫营养的湖泊的退化。我们表明，AA大多是自生的，AA占浮游生物，POM和沉积物中有机物质的5–45％。基于AA的细菌返工（ΣV）或营养级（TL）代理在水柱中显示出增加的值，但在沉积物中显示出相对稳定的值。此外，¹³ C AA值（-30至-60‰）。