浙江大学蒋明凯和澳大利亚西悉尼大学Crous Kristine Y.团队合作取得一项新突破。他们的研究发现微生物对磷的竞争限制了成熟森林的二氧化碳的反应。相关论文于2024年6月5日发表在《自然》杂志上。

据研究人员介绍，随着CO₂浓度的上升，陆地生态系统吸收额外碳(C)的能力取决于土壤养分有效性。以前的证据表明，生长在缺磷(P)土壤上的成熟森林在CO₂升高的情况下吸收额外生物量的能力有限。然而，对生态系统P循环及其CO₂响应的不确定性，是气候变化下陆地碳汇机制预测的关键瓶颈。

通过编制第一个综合P预算，研究人员发现土壤微生物捕获的磷很可能，限制了生态系统磷的循环和植物吸收的有效性。树木可以有效地吸收磷，但微生物对矿化土壤磷的抢占似乎限制了树木，在CO₂升高下增加磷吸收和同化的能力，从而限制了它们吸收额外碳的能力。

植物刺激微生物磷循环和植物磷吸收的策略，如增加根际碳向土壤的释放，可能是限制磷的森林增加碳捕获到新生物量的必要条件。研究结果确定了磷有效性限制树木生长的CO₂碳施肥的关键机制，并将指导地球系统模型的发展，以预测未来的长期碳储存。

附：英文原文

Title: Microbial competition for phosphorus limits the CO₂ response of a mature forest

Author: Jiang, Mingkai, Crous, Kristine Y., Carrillo, Yolima, Macdonald, Catriona A., Anderson, Ian C., Boer, Matthias M., Farrell, Mark, Gherlenda, Andrew N., Castaeda-Gmez, Laura, Hasegawa, Shun, Jarosch, Klaus, Milham, Paul J., Ochoa-Hueso, Rul, Pathare, Varsha, Pihlblad, Johanna, Pieiro, Juan, Powell, Jeff R., Power, Sally A., Reich, Peter B., Riegler, Markus, Zaehle, Snke, Smith, Benjamin, Medlyn, Belinda E., Ellsworth, David S.

Issue&Volume: 2024-06-05

Abstract: The capacity for terrestrial ecosystems to sequester additional carbon (C) with rising CO₂ concentrations depends on soil nutrient availability. Previous evidence suggested that mature forests growing on phosphorus (P)-deprived soils had limited capacity to sequester extra biomass under elevated CO₂ , but uncertainty about ecosystem P cycling and its CO₂ response represents a crucial bottleneck for mechanistic prediction of the land C sink under climate change. Here, by compiling the first comprehensive P budget for a P-limited mature forest exposed to elevated CO₂, we show a high likelihood that P captured by soil microorganisms constrains ecosystem P recycling and availability for plant uptake. Trees used P efficiently, but microbial pre-emption of mineralized soil P seemed to limit the capacity of trees for increased P uptake and assimilation under elevated CO₂ and, therefore, their capacity to sequester extra C. Plant strategies to stimulate microbial P cycling and plant P uptake, such as increasing rhizosphere C release to soil, will probably be necessary for P-limited forests to increase C capture into new biomass. Our results identify the key mechanisms by which P availability limits CO₂ fertilization of tree growth and will guide the development of Earth system models to predict future long-term C storage.

DOI: 10.1038/s41586-024-07491-0

Source: https://www.nature.com/articles/s41586-024-07491-0