青藏高原草甸土微生物活性对不同冻融循环次数的非线性响应
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黄伟(2000-),男,硕士研究生,主要从事土壤冻融研究。E-mail:huangwei221@mails.ucas.ac.cn

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S154.3

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国家自然科学基金项目(52279049,42477373)


Nonlinear Response of Microbial Activity in Meadow Soils on Qinghai-Xizang Plateau to Different Numbers of Freeze-Thaw Cycles
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    摘要:

    [目的] 青藏高原草甸土对气候变化引起的季节性冻融频次改变尤为敏感,亟须揭示草甸土微生物活性对不同冻融循环次数的响应规律。[方法] 选取青藏高原地区季节性冻融作用频繁的高寒草甸土为研究对象,通过非冻融与1、3、5、7、9次冻融循环模拟,对比分析典型土壤可溶性碳氮、微生物碳氮及气体碳氮的响应特征。[结果] 1)与未冻融土壤相比,9次冻融循环后土壤微生物生物量碳显著降低23.64%,可溶性有机碳质量分数显著提升7.37%,CO2和N2O累积释放量分别增加71.09%和321.40%。2)随着冻融循环次数增加,可溶性有机碳、β-葡萄糖苷酶和亮氨酸氨基肽酶等活性呈先减小后增大的非线性变化特征,均于第5次冻融循环后达到最低值;同时CO2释放速率在前2次冻融循环后最高(为非冻融土壤的1.83倍),而N2O释放速率则在第5次冻融循环后激增,达非冻融土壤的5.83~24.82倍。3)多次冻融循环后,土壤微生物生物量氮变化不显著,但NO3--N质量分数和乙酰氨基葡萄糖苷酶活性稳步增多,而NH4+-N则稳步下降。[结论] 多次冻融循环对土壤微生物的影响并非单次冻融作用的简单重复。高寒草甸土5次冻融循环后,土壤水冻胀作用带来的孔隙结构变化和微生物死亡已基本趋于稳定,而存活微生物群落则逐渐适应新的温度条件,在进一步的冻融循环中恢复活性,研究结果为深入理解高寒草甸土微生物越冬机理提供新理论和新数据。

    Abstract:

    [Objective] Meadow soils on the Qinghai-Xizang Plateau are highly sensitive to changes in the frequency of seasonal freeze-thaw cycles caused by climate change,and it is therefore urgent to understand how microbial activity in these soils responds to different numbers of freeze-thaw cycles. [Methods] Typical alpine meadow soil from a region of the Qinghai-Xizang Plateau with frequent seasonal freeze-thaw activity was selected as the study subject. Simulations with 1,3,5,7,and 9 freeze-thaw(FT)cycles(termed C1,C3,C5,C7,and C9)and a non-freeze-thaw control(N9)were conducted to compare the response characteristics of typical soil parameters:dissolved organic carbon(DOC),microbial biomass carbon and nitrogen,and gaseous carbon and nitrogen. [Results] 1)Compared with the non-FT treatment(N9),soil microbial biomass carbon(SMBC) decreased significantly by 23.64% after C9,while DOC increased significantly by 7.37%,and the cumulative emissions of CO2 and N2O increased by 71.09% and 321.40%,respectively. 2)With increasing FT cycles,DOC content and activities such as β -glucosidase and leucine aminopeptidase showed a nonlinear trend:they first declined and reached minimum levels at C5. The CO2 emissions rates peaked after the first two freeze-thaw cycles (1.83 times that of the non-FT soil),while N2O emission rates sharply increased after the fifth cycle,reaching 5.83 to 24.82 times that of the non-FT soil. 3) Soil microbial biomass nitrogen (SMBN) did not vary significantly,but the concentrations of NO3--N and the activity of N-acetylglucosaminidase(NAG)increased steadily,while NH4+-N decreased steadily,as the number of FT cycles increased. [Conclusion] The effects of multiple freeze-thaw cycles on soil microorganisms are not merely repetitions of a single freeze-thaw event. After five cycles,changes in pore structure and microbial mortality caused by soil water freezing and swelling have largely stabilized,and the surviving microbial communities gradually adapt to the new temperature conditions, restoring their activity during subsequent cycles. These findings could provide new theoretical insights and data for understanding the overwintering mechanisms of microorganisms in alpine meadow soils affected by seasonal freeze-thaw cycles.

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黄伟, 杨小艺, 李浩乐, 胡亚鲜.青藏高原草甸土微生物活性对不同冻融循环次数的非线性响应[J].水土保持学报,2025,39(5):256~263

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  • 收稿日期:2025-03-03
  • 最后修改日期:2025-04-02
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  • 在线发布日期: 2025-10-20
  • 出版日期: 2025-10-28
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