图1 地球生态系统生物地球化学循环示意图 (修改自 https://agriculturistmusa.com/)

Fig.1 Schematic of Earth's ecosystem biogeochemical cycles

图2 重要参数在地球行星边界的存在状态和变化趋势(引自文献[49])

Fig.2 Current status of control variables for all nine planetary boundaries. Adapted from [49].

图3 宏组学与同位素标记示踪技术联合应用以解析生物地球化学过程中微生物与环境的相互作用 图中①表示代谢活跃的生物细胞吸收同化了同位素标记的底物,通过MAR-/NanoSIMS可以被观测识别;②表示基于不同生化反应途径的稳定同位素分馏效应差异,通过监测代谢产物中的稳定同位素丰度,可分析主导代谢途径;或利用同位素标记底物,监测生化反应中底物和代谢产物中标记元素的流通量,可定量识别代谢途径。

Fig.3 Combined application of metaOmics and isotope labeling or signature techniques to decipher the interactions between microorganisms and the environment in biogeochemical processes DNA-based analytical techniques, such as high-throughput sequencing of marker genes represented by SSU rRNA genes and metagenomes followed with construction of metagenome-assembled genomes, allow for the analyses of microbial community composition, phylogenetic classification of species, and the functional potential of species and communities. RNA-based metatranscriptomics is utilized to analyze gene transcription levels and to identify key metabolic pathways. Subcellular localization and regulation occur at the protein level. Post-translational modifications can alter the location and function of proteins. Consequently, metaproteomics and metabolomics reflect the expression and activity of functional proteins. Combined with stable or radioactive isotope labeling or signature techniques, visualization methods based on isotope and elemental imaging are employed to observe and enumerate metabolically active cells, enabling quantitative analyses of substrate update and transform rates, pathway composition, and nutrient fluxes. ① represents that, the metabolically active cells update and assimilate the isotope-labeled substrates, which are then can be observed and identified via the MAR- or nanoSIMS methods. ② express that, different stable isotope fractionation effects exist in different biochemical reactions or pathways, leading to different isotope signatures of products, which enables identification of predominant metabolic pathway by analyzing the natural stable isotope composition; on the other hand, by tracing the flux of labeled isotopes in the substrates and metabolic products, the metabolic pathways can be quantitatively calculated. The integrated application of these techniques facilitates the study, across multiple levels and different spatiotemporal scales, of the adaptation-feedback relationship between organisms and their environment, as well as the roles they played in biogeochemical processes, such as the interaction between microbial functional groups driving the coupled cycle of sulfur and CH4 in the ocean. Such research has revealed that, the convergence of global organic metabolic functions shapes biochemical gradients in the oceans, such as concentrations of SO 4 2 -, H2S, CH4 at different depths, leading to the formation of ecological niches for different microbial functional groups, and fostering co-evolution between life and the marine environment.

图4 “转化”生物地球化学概念反应的社会与生态系统生物地球化学系统之间的双向反馈作用(引自文献[64])

Fig.4 Translational biogeochemistry: bidirectional feedbacks between social and Earth's biogeochemical systems. Adapted from [64].