Thermal stratification is a critical physical process controlling carbon (C) flux from lakes into the atmosphere. In general, vertical water temperature profiles in shallow subtropical lakes can vary significantly because typhoons frequently induce vertical mixing across the entire lake due to strong winds and rapid flushing from river inputs. Since C fluxes are driven by dissolved inorganic C (DIC), it is necessary to understand stratification's influence on DIC dynamics in shallow subtropical lakes. Therefore, we aimed to clarify the impact of stratification on DIC in Yuan‐Yang Lake, a typical shallow subtropical mountain lake, by developing a net ecosystem production (NEP) model. We measured the vertical profile of water temperature and DIC once or twice a month from July 2004 to December 2017. We applied a three‐dimensional hydrological model to estimate residence time and NEP, which revealed that large amounts of DIC are stored in the lower layer from spring to summer due to the suppression of vertical mixing by stratification. In autumn and winter, the lake was well mixed, and DIC was evenly distributed in the water column due to vertical mixing. This was confirmed by vertical DIC profiles.

中文翻译：

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热分层对浅亚热带湖泊季节性净生态系统生产和溶解无机碳的影响

热分层是控制从湖泊到大气中的碳（C）通量的关键物理过程。通常，由于强风和河流输入物的快速冲刷，台风经常在整个湖泊中引起垂直混合，因此在亚热带浅水湖泊中，垂直水温曲线可能会有很大变化。由于碳通量是由溶解的无机碳（DIC）驱动的，因此有必要了解分层对浅亚热带湖泊DIC动力学的影响。因此，我们旨在通过开发净生态系统生产（NEP）模型来阐明分层对元阳湖（典型的亚热带浅水高山湖泊）中DIC的影响。从2004年7月到2017年12月，我们每月一次或两次测量水温和DIC的垂直剖面图。我们应用了三维水文模型来估计停留时间和NEP，这表明由于分层抑制了垂直混合，从春季到夏季，大量DIC储存在下层。在秋天和冬天，湖泊混合得很好，由于垂直混合，DIC均匀地分布在水柱中。垂直DIC轮廓证实了这一点。