The continental silicon (Si) cycle, including terrestrial and freshwater ecosystems (lakes, rivers, estuaries), acts as a filter and modulates the amount of Si transported to the oceans. In order to link the variation in the terrestrial Si cycle to aquatic ecosystems, knowledge on changes in vegetation cover, soil disturbance and the impact of human activity are required. This study on varved lake sediments from Tiefer See near Klocksin (TSK) in northeastern Germany investigates Si isotope variations in diatom frustules (δ³⁰Si_diatom) over the last ∼4300 years. δ³⁰Si_diatom values vary between 0.37 and 1.63‰. The isotopic signal measured in centric (mostly planktonic) and pennate (mostly benthic) diatoms shows the same trend through most of the record. A decrease in δ³⁰Si_diatom coinciding with early deforestation between 3900 and 750 a BP in the catchment area, points to an enhanced export of isotopically light dissolved silica (DSi) from adjacent soils to the lake. The burial flux of biogenic silica (BSi) observed in the lake sediments increases with cultivation due to enhanced nutrient supply (N, P and Si) from the watershed and nutrient redistribution caused by wind-driven increased water circulation. When the cultivation intensifies, we observe a shift to higher δ³⁰Si_diatom values that we interpret to reflect a diminished Si soil pool and the preferential removal of the lighter ²⁸Si by crop harvesting. Human activity influences the DSi supply from the catchment and appears to be the primary driver controlling the Si budget in TSK. Our data shows how land use triggers variations in continental Si cycling on centennial timescales and provides important information on the underlying processes.

包括陆地和淡水生态系统（湖泊，河流，河口）在内的大陆硅（Si）循环起到过滤器的作用，并调节输送到海洋的硅的量。为了将陆地硅周期的变化与水生生态系统联系起来，需要有关植被覆盖，土壤扰动和人类活动影响的知识。从Tiefer见varved湖泊沉积物克洛克辛（TSK）在德国东北部附近的这项研究调查了硅藻硅藻硅同位素的变化（δ ³⁰硅_硅藻）过去~4300年。δ ³⁰的Si_硅藻值在0.37至1.63‰之间变化。在大多数记录中，在中心（大部分为浮游性）和戊状（大部分为底栖）硅藻中测得的同位素信号显示出相同的趋势。在δ的减少³⁰的Si_硅藻在集水区3900和750之间BP早期砍伐重合，指向同位素光溶解的二氧化硅的（DSI）从邻近的土壤湖边增强的出口。湖泊沉积物中观察到的生物硅（BSi）的埋藏通量随着耕作的增加而增加，这是由于流域的营养物供应（N，P和Si）增加以及风驱动的水循环增加引起的营养物再分配所致。当栽培加剧，我们观察到的移位至更高的δ ³⁰的Si_硅藻我们将这些值解释为反映了Si土壤库的减少以及通过作物收获而优先去除了较轻的²⁸ Si。人类活动会影响流域的DSi供应，并且似乎是控制TSK中Si预算的主要驱动力。我们的数据显示了土地利用如何触发百年时间尺度上的大陆硅循环变化，并提供了有关潜在过程的重要信息。