Abstract Lake monitoring studies are essential for understanding the modern biogeochemical and sedimentological cycles to enable and support the interpretation of paleolimnological records. However, such studies remain scarce for high-altitude lakes in general and specifically for lakes on the Tibetan Plateau. We investigated the hydro-chemical and physical properties of lake Nam Co and its twenty-one major inflowing rivers from 2011 to 2013. The modern sediment flux and sediment properties were determined for samples collected by sediment traps deployed for the same study period at different water depths at three sites in Nam Co. Carbonate weathering in the catchment, especially pronounced during the monsoon season, was identified as the predominant origin of dissolved riverine hydrochemical components. The sediment budget shows remarkable temporal variation, with trends of intensified sediment fluxes during the non-monsoon season and small variations within the monsoon season. Spatially, considerably higher sedimentation fluxes were detected in nearshore sites (T1 and T3) and attributed to wind-induced resuspension. Vertically, resuspension is also an important factor that influences the sedimentation process, which leads to an exponential increase of the budget from the surface to the bottom layer. Autochthonous carbonate deposition rates presented a similar seasonal pattern, with the total sedimentation rates under the influence of the water balance. Low values occurred during the monsoon season due to dilution while deposition rapidly increased during the early post-monsoon season when the lake level decreased. Intensive carbonate deposition also occurred during the non-monsoon season, which dominated the lake hydrochemistry dynamics.

中文翻译：

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青藏高原纳木错盆地水化学和现代沉积过程的时空变化：对碳酸盐沉淀的影响

摘要 湖泊监测研究对于理解现代生物地球化学和沉积学循环至关重要，以实现和支持古湖泊记录的解释。然而，对于一般高海拔湖泊，特别是青藏高原湖泊，此类研究仍然很少。2011 年至 2013 年，我们调查了 Nam Co 湖及其 21 条主要流入河流的水化学和物理性质。对同一研究期间在不同水域部署的沉积物捕集器收集的样品确定了现代沉积物通量和沉积物性质Nam Co 三个地点的深度。集水区的碳酸盐风化，特别是在季风季节，被确定为溶解的河流水化学成分的主要来源。沉积物收支具有显着的时间变化，非季风季沉积物通量呈增强趋势，季风季变化较小。在空间上，在近岸地点（T1 和 T3）检测到相当高的沉降通量，这归因于风引起的再悬浮。纵向上，再悬浮也是影响沉积过程的重要因素，导致从地表到底层的收支呈指数增长。本土碳酸盐沉积速率呈现出类似的季节性模式，总沉积速率受水平衡的影响。由于稀释，季风季节期间出现低值，而在湖水位下降的季风后早期，沉积物迅速增加。