Trophic state index (TSI) can assess lake trophic status and trace in-situ metabolism, exhibiting a high potential in explaining autochthonous carbon dioxide (CO₂) in aquatic environments. However, there remains a knowledge gap in how TSI links to the partial pressure of CO₂ (pCO₂) generated and consumed in lakes. Here we explored the temporal variations of lake pCO₂ and TSI, as well as their linkages in a karst plateau lake. Lake pCO₂ ranged from 90.1 to 7169.3 μatm and was significantly high in the post-wet period (2534.3 ± 1637.9 μatm). Over 58% of samples were found to be supersaturated in CO₂ with respect to the atmospheric equilibrium (410 μatm). Biological and hydrological processes regulated lake trophic status, resulting in mesotrophic state (30 < TSI < 50) in the post-wet period and eutrophic state (TSI > 50) in the drought and initial-wet periods. Coupled carbonate dissolution and photosynthesis consumed the pCO₂, whereas groundwater and respiration contributed the pCO₂ in the karst lake. Our results highlighted that lake TSI could decipher trophic status and further partially explain the pCO₂ dynamics and sources.

营养状态指数（TSI）可以评估湖泊的营养状态并追踪原位代谢，在解释水生环境中的原生碳（CO ₂）方面具有很高的潜力。但是，在TSI与湖泊中产生和消耗的CO ₂（p CO ₂）分压之间的联系方面，仍然存在知识差距。在这里，我们探讨了喀斯特高原湖泊中p CO ₂和TSI湖泊的时空变化以及它们之间的联系。Lake p CO _2的范围从90.1到7169.3μatm，并且在湿后时期显着较高（2534.3±1637.9μatm）。发现超过58％的样品在CO中过饱和₂相对于大气平衡（410μatm）。生物和水文过程调节了湖泊的营养状态，在干旱后的湿润时期导致了中营养状态（30 <TSI <50），而在干旱和湿润的初期则形成了营养状态（TSI> 50）。碳酸盐溶解和光合作用相结合消耗了p CO ₂，而地下水和呼吸作用在喀斯特湖中贡献了p CO ₂。我们的结果表明，TSI湖可以解释营养状态，并进一步部分解释p CO _2的动力学和来源。