Reforestation accelerates soil organic carbon accumulation: Evidence from microbial biomarkers
Reforestation accelerates soil organic carbon accumulation: Evidence from microbial biomarkers
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DOI：
10.1016/j.soilbio.2019.01.012
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发表时间：
2019-04
影响因子：
9.7
通讯作者：
Pengshuai Shao;C. Liang;L. Lynch;Hongtu Xie;Xuelian Bao
中科院分区：
文献类型：
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作者：
Pengshuai Shao;C. Liang;L. Lynch;Hongtu Xie;Xuelian Bao
土壤在地下储存的碳(C)比植物和大气加起来还要多，提供了重要的生态系统服务。虽然以前的研究表明，可持续森林管理实践可以通过提高植物生产力来增加土壤C的储存，但土壤微生物的作用仍然难以捉摸。我们分析了植被凋落物、土壤C和微生物参数在再造林时间序列中的变化——平均林龄为~ 20、80、120、200和 ≥ 300年——以评估微生物群落如何调节土壤C的转化和封存。我们观察到微生物生物量（脂质生物标志物）、微生物坏死块（氨基糖生物标志物）和土壤有机碳随林龄的增加大致一致，突出了微生物对土壤碳积累的调节。具体而言，微生物生物量的增加先于土壤C的增加，这表明微生物脂质是生态系统恢复的早期敏感指标。我们还观察到，在恢复80-200年的森林中，微生物坏死块相对于土壤C迅速增加，这可能是由于微生物周转速度加快。这些模式表明，在再造林的早期和中期，较高的植物生产力（低凋落物C: N比）有利于微生物的有效生长和有机碳储量的坏死块积累。随着森林年龄的增长，微生物坏死团对有机碳库的贡献向背景水平下降。我们的研究结果表明，重新造林提供了一个积极的反馈解决方案，通过有效地将土壤C封存在地下来缓解气候变化。
Soils store more carbon (C) belowground than plants and the atmosphere combined, providing a critical ecosystem service. While previous research has shown that sustainable forest management practices can increase soil C storage by enhancing plant productivity, the role of soil microbes remains elusive. We analyzed changes in plant litter, soil C, and microbial parameters across a reforestation chronosequence—with average stand ages of ∼20, 80, 120, 200 and ≥ 300 years—to evaluate how microbial communities mediate soil C transformation and sequestration. We observed generally consistent increases in microbial biomass (lipid biomarkers), microbial necromass (amino sugar biomarkers), and soil organic C with forest age, highlighting microbial regulation of soil C accumulation. Specifically, increases in microbial biomass preceded gains in soil C, suggesting microbial lipids are an early and sensitive indicator of ecosystem restoration. We also observed a rapid increase in microbial necromass relative to bulk soil C in forests restored for 80–200 years, likely due to accelerated microbial turnover rates. These patterns suggest high plant productivity (low litter C: N ratios) during the early and middle stages of reforestation facilitates efficient microbial growth and necromass accrual in SOC stocks. As forests age, the contribution of microbial necromass to the SOC pool declines toward background levels. Our results suggest reforestation offers a positive feedback solution that mitigates climate change by efficiently sequestering soil C belowground.