Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
Department of Environmental Biotechnology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany.
Glob Chang Biol. 2019 Nov;25(11):3578-3590. doi: 10.1111/gcb.14781. Epub 2019 Sep 18.
Soil carbon transformation and sequestration have received significant interest in recent years due to a growing need for quantitating its role in mitigating climate change. Even though our understanding of the nature of soil organic matter has recently been substantially revised, fundamental uncertainty remains about the quantitative importance of microbial necromass as part of persistent organic matter. Addressing this uncertainty has been hampered by the absence of quantitative assessments whether microbial matter makes up the majority of the persistent carbon in soil. Direct quantitation of microbial necromass in soil is very challenging because of an overlapping molecular signature with nonmicrobial organic carbon. Here, we use a comprehensive analysis of existing biomarker amino sugar data published between 1996 and 2018, combined with novel appropriation using an ecological systems approach, elemental carbon-nitrogen stoichiometry, and biomarker scaling, to demonstrate a suit of strategies for quantitating the contribution of microbe-derived carbon to the topsoil organic carbon reservoir in global temperate agricultural, grassland, and forest ecosystems. We show that microbial necromass can make up more than half of soil organic carbon. Hence, we suggest that next-generation field management requires promoting microbial biomass formation and necromass preservation to maintain healthy soils, ecosystems, and climate. Our analyses have important implications for improving current climate and carbon models, and helping develop management practices and policies.
近年来，由于需要量化土壤碳转化和固存在缓解气候变化方面的作用，土壤碳转化和固存受到了极大关注。尽管我们对土壤有机质性质的理解最近有了很大的修正，但对于微生物残体作为持久性有机质的一部分的定量重要性仍然存在基本的不确定性。解决这一不确定性的障碍是缺乏定量评估微生物物质是否构成土壤中大部分持久性碳的方法。由于与非微生物有机碳存在重叠的分子特征，土壤中微生物残体的直接定量非常具有挑战性。在这里，我们使用了 1996 年至 2018 年间发表的生物标志物氨基糖现有数据的综合分析，结合生态系统方法、元素碳-氮化学计量和生物标志物比例的新应用，来证明了一套策略，用于量化微生物衍生碳对全球温带农业、草原和森林生态系统表土有机碳库的贡献。我们表明，微生物残体可以占土壤有机碳的一半以上。因此，我们建议下一代田间管理需要促进微生物生物量的形成和残体的保存，以维持健康的土壤、生态系统和气候。我们的分析对改进当前的气候和碳模型，以及帮助制定管理实践和政策具有重要意义。
