State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
Sci Total Environ. 2024 Nov 20;952:175860. doi: 10.1016/j.scitotenv.2024.175860. Epub 2024 Aug 28.
Eutrophication triggered by internal phosphorus (P) poses a substantial threat to the biodiversity of organisms in freshwater ecosystems. However, little is known about the linkages between P resource partitioning and microbial succession, especially in karst sediments. Here, we studied the diversity patterns and assembly processes of bacterial and archaeal communities in sediment cores from two historically hyper-eutrophicated karst lakes, Hongfeng Lake and Aha Lake, and investigated the relative contribution of P fractions to them. Our null and neutral models consistently indicated that bacterial and archaeal community assembly was judged to be deterministic rather than stochastic. We found a monotonically decreasing pattern for bacterial Shannon diversity toward deep sediments in Aha Lake, but U- or hump-shaped patterns for archaea in Hongfeng and Aha Lakes. Intriguingly, the community dissimilarity Bray-Curtis of bacteria and archaea consistently increased with increasing depth distance, with slopes of 0.0080 and 0.0069 in Hongfeng Lake and 0.0078 and 0.0087 in Aha Lake, respectively. Such cross-taxon congruence was well-supported by equivalent ecological processes (i.e., environmental selection). For bacteria and archaea, Shannon diversity was primarily affected by the total P (TP) fractions such as the loosely adsorbed TP or calcium-bound TP and sediment TP. Their community composition was significantly (P < 0.05) affected by calcium-bound inorganic P (Pi), loosely adsorbed Pi and reductant-soluble Pi. Although sediment properties were important, bacterial and archaeal diversity or community composition were well-explained by the Pi fractions, with high direct or indirect effects. In particular, Pi fractions exhibited stronger effects on bacterial and archaeal characteristics than organic P fractions. Taken together, our study provides novel insights into the ecological importance of P resource partitioning to microbial succession, which has crucial implications for disentangling the biogeochemical processes of P cycling in aquatic ecosystems.
富营养化是由内部磷（P）引发的，对淡水生态系统中生物的生物多样性构成了重大威胁。然而，人们对 P 资源分配与微生物演替之间的联系知之甚少，特别是在喀斯特沉积物中。在这里，我们研究了来自两个历史上高度富营养化的喀斯特湖泊——红枫湖和阿哈湖的沉积物核心中细菌和古菌群落的多样性模式和组装过程，并调查了 P 分数对它们的相对贡献。我们的零假设和中性模型一致表明，细菌和古菌群落的组装被判断为确定性的，而不是随机的。我们发现阿哈湖的细菌 Shannon 多样性朝着深沉积物呈单调递减模式，但在红枫湖和阿哈湖的古菌中呈 U 形或驼峰形模式。有趣的是，细菌和古菌群落的不相似性 Bray-Curtis 随着深度距离的增加而持续增加，在红枫湖的斜率为 0.0080 和 0.0069，在阿哈湖的斜率为 0.0078 和 0.0087。这种跨分类群的一致性很好地支持了等效的生态过程（即环境选择）。对于细菌和古菌，Shannon 多样性主要受总磷（TP）分数的影响，如松散吸附的 TP 或钙结合的 TP 和沉积物 TP。它们的群落组成受钙结合无机磷（Pi）、松散吸附 Pi 和还原剂可溶性 Pi 的显著影响（P < 0.05）。尽管沉积物性质很重要，但 Pi 分数很好地解释了细菌和古菌的多样性或群落组成，具有较高的直接或间接影响。特别是，Pi 分数对细菌和古菌特征的影响大于有机 P 分数。总之，我们的研究为 P 资源分配对微生物演替的生态重要性提供了新的见解，这对于阐明水生生态系统中 P 循环的生物地球化学过程具有至关重要的意义。
