Abstract：
In recent years, the global carbon cycle has garnered significant research attention. However, details of the intricate relationship between planktonic bacteria, hydrochemistry, and dissolved organic matter (DOM) in inland waters remain unclear, especially their effects on lake carbon sequestration. In this study, we analyzed 16S rRNA, chromophoric dissolved organic matter (CDOM), and inorganic nutrients in Erhai Lake, Yunnan Province, China. The results revealed that allochthonous DOM (C3) significantly regulated the microbial community, and that autochthonous DOM, generated via microbial mineralization (C2), was not preferred as a food source by lake bacteria, and neither was allochthonous DOM after microbial mineralization (C4). Specifically, the correlation between the fluorescence index and functional genes (FAPRPTAX) showed that the degree of utilization of DOM was a critical factor in regulating planktonic bacteria associated with the carbon cycle. Further examination of the correlation between environmental factors and planktonic bacteria revealed that Ca2+ had a regulatory influence on the community structure of planktonic bacteria, particularly those linked to the carbon cycle. Consequently, the utilization strategy of DOM by planktonic bacteria was also determined by elevated Ca2+ levels. This in turn influenced the development of specific recalcitrant autochthonous DOM within the high Ca2+ environment of Erhai Lake. These findings are significant for the exploration of the stability of DOM within karst aquatic ecosystems, offering a new perspective for the investigation of terrestrial carbon sinks.
摘要：
近年来,全球碳循环已经获得了重要的研究关注。然而,浮游细菌之间复杂关系的细节，水化学,内陆水域中的溶解有机物(DOM)仍不清楚，尤其是它们对湖泊碳固存的影响。在这项研究中,我们分析了16SrRNA，发色溶解有机物（CDOM），洱海中的无机养分，云南省,中国。结果表明，异源DOM（C3）显著调节微生物群落，还有那个土生土长的DOM，通过微生物矿化(C2)产生，不是湖泊细菌首选的食物来源，微生物矿化(C4)后也不是异源DOM。具体来说,荧光指数与功能基因（FAPRPTAX）之间的相关性表明，DOM的利用程度是调节与碳循环相关的浮游细菌的关键因素。进一步研究环境因素与浮游细菌之间的相关性，发现Ca2对浮游细菌的群落结构具有调节作用，特别是那些与碳循环有关的。因此,浮游细菌对DOM的利用策略也取决于Ca2水平的升高。这反过来又影响了洱海高Ca2环境中特定的顽固自生DOM的发展。这些发现对于探索喀斯特水生生态系统中DOM的稳定性具有重要意义。为研究陆地碳汇提供了新的视角。
