水体硅碳化学计量趋同的浮游植物驱动机制  

The mechanism of phytoplankton-driven silicon and carbon stoichiometric convergence in water

作　　者：李婉珠 王宝利[1,2] 刘丛强 LI Wanzhu;WANG Baoli;Liu Cong-Qiang(Research Center for Watershed Biogeochemical Cycle,School of Earth System Science,Tianjin University,Tianjin 300072,China;Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station,Tianjin 300072,China)

机构地区：[1]天津大学地球系统科学学院流域生物地球化学循环研究中心,天津300072 [2]天津环渤海滨海地球关键带国家野外科学观测研究站,天津300072

出　　处：《地学前缘》2025年第3期311-319,共9页Earth Science Frontiers

基　　金：国家自然科学基金项目(42293264,42293262);国家资助博士后研究人员计划(GZC20241196)。

摘　　要：浮游植物元素化学计量比对其生境中营养元素可利用性变化的响应与反馈研究,是理解水生生态系统结构和功能相互关系的关键要素。水体中硅(Si)碳(C)化学计量比的动态变化一定程度上能够反映其中Si-C生物地球化学循环的耦合关系,但目前浮游植物Si∶C计量比与溶解硅(DSi)和CO_(2)浓度的相互作用模式和潜在机制尚不清楚。在此,我们发现湖泊浮游植物Si∶C摩尔比随年际变化趋向于与其生境中DSi∶CO_(2)摩尔比一致(即硅碳化学计量趋同),且这种趋同是由浮游植物群落演替来驱动的。不同类型内陆水体(河流、湖泊、水库和湿地)大空间尺度调查结果显示浮游植物Si∶C摩尔比和DSi∶CO_(2)摩尔比空间差异显著,大都偏离Redfield比例。随机森林分析显示,硅藻门相对丰度、水温和溶解无机氮是浮游植物Si∶C比形成的重要预测因子。宏转录组学证据表明,伴随着浮游植物群落演替,其分子水平上蛋白质周转响应并反馈DSi∶CO_(2)比变化,进而导致水体硅碳化学计量趋同。这些发现为水体浮游植物化学计量学的认识提供了新的见解。硅碳化学计量趋同在一定程度上可以表征表层地球系统岩石圈、水圈和生物圈之间的相互作用,并为描述水生生态系统结构和功能对环境变化的响应提供了一种定量模式。The response and feedback of phytoplankton elemental stoichiometry to their ambient available nutrients is a vital approach to understand the relationship between structure and function of aquatic ecosystems.The change of silicon(Si)to carbon(C)stoichiometric ratio in water can reflect the coupling of Si-C biogeochemical cycles to some extent;however,the pattern of phytoplankton Si∶C ratio interacting with the ambient dissolved silicon(DSi)and CO_(2) and the underlying mechanisms are still unclear yet.Here,we found that phytoplankton Si∶C molar ratio converged towards the DSi∶CO_(2) molar ratio with years(i.e.,Si-C stoichiometric convergence),and this convergence was driven by phytoplankton community succession in lakes.The large-scale survey across different inland waters(including rivers,lakes,reservoirs,and wetlands)showed that there was significant spatial difference in phytoplankton Si∶C and DSi∶CO_(2) molar ratios,and most of them deviated greatly from the Redfield ratio.Random forest analysis indicated that the relative abundance of diatoms,water temperature,and dissolved inorganic nitrogen were important predictive factors for phytoplankton Si∶C ratio.Metatranscriptomic evidence suggested that phytoplankton community succession and its matched protein turnover in response to the changing DSi∶CO_(2) ratio resulted in a Si-C stoichiometric convergence in water.The study will provide some new insights into phytoplankton stoichiometry,and the Si-C stoichiometric convergence could characterize the interaction between the lithosphere,hydrosphere,and biosphere in surface-earth system to some extent and provide a quantitative pattern for describing the structure and function of aquatic ecosystems in response to environmental changes.

关 键 词：水生生态系统 浮游植物 化学计量比 群落组成 宏转录组 

分 类 号：P593[天文地球—地球化学] X171[天文地球—地质学]