Plant-microbial linkages underpin carbon sequestration in contrasting mountain tundra vegetation types
Plant-microbial linkages underpin carbon sequestration in contrasting mountain tundra vegetation types
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DOI：
10.1016/j.soilbio.2021.108530
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发表时间：
2022-02-01
影响因子：
9.7
通讯作者：
Dorrepaal, Ellen
中科院分区：
文献类型：
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作者：
Gavazov, Konstantin;Canarini, Alberto;Dorrepaal, Ellen
苔原生态系统拥有大量的土壤有机质（SOM），可能是由于低温限制的微生物SOM分解速率超过植物初级生产力和微生物necromass输入的SOM积累。在这里，我们测试的假设，不同的苔原植被类型和他们的碳供应特征根际微生物确定SOM循环独立的温度。在亚北极的斯堪的纳维亚，我们使用了三因素析因设计，在两个海拔高度的每一个高度上都有成对的石南和草甸植被，并且在一个生长季节期间，植被类型和海拔的每一种组合都受到环境光（即，环境植物生产力），或95%遮蔽（即，降低工厂生产率）。我们通过单变量和多变量方差分析以及结构方程模型评估了潜在的地上和地下生态系统联系。我们观察到苔原植被类型和微生物群落组成和功能之间的直接耦合，这支撑了生态系统的SOM存储的潜力。低海拔和环境光下更大的初级生产力支持更高的微生物生物量和氮固定化，同时具有更低的微生物量比酶活性和SOM腐殖化作用。相应地，较大的SOM在较低的海拔和健康持续的真菌为主的微生物群落，这是不太底物限制，并投资较少的酶SOM矿化，由于更大的碳利用效率（CUE）。我们的研究结果强调了苔原植物群落特征的重要性（即，生产力和植被类型），通过它们对土壤微生物群落的大小，结构和生理的影响，作为有机质周转的重要驱动力。这里记录的协调一致的模式在地上和地下生态系统功能是强烈支持使用植物群落特征作为替代评估冻原碳储存潜力及其在气候和植被变化下的演变。
Tundra ecosystems hold large stocks of soil organic matter (SOM), likely due to low temperatures limiting rates of microbial SOM decomposition more than those of SOM accumulation from plant primary productivity and microbial necromass inputs. Here we test the hypotheses that distinct tundra vegetation types and their carbon supply to characteristic rhizosphere microbes determine SOM cycling independent of temperature. In the subarctic Scandes, we used a three-way factorial design with paired heath and meadow vegetation at each of two elevations, and with each combination of vegetation type and elevation subjected during one growing season to either ambient light (i.e., ambient plant productivity), or 95% shading (i.e., reduced plant productivity). We assessed potential above-and belowground ecosystem linkages by uni-and multivariate analyses of variance, and structural equation modelling. We observed direct coupling between tundra vegetation type and microbial community composition and function, which underpinned the ecosystem's potential for SOM storage. Greater primary productivity at low elevation and ambient light supported higher microbial biomass and nitrogen immobilisation, with lower microbial mass-specific enzymatic activity and SOM humification. Congruently, larger SOM at lower elevation and in heath sustained fungal-dominated microbial communities, which were less substrate-limited, and invested less into enzymatic SOM mineralisation, owing to a greater carbon-use efficiency (CUE). Our results highlight the importance of tundra plant community characteristics (i.e., productivity and vegetation type), via their effects on soil microbial community size, structure and physiology, as essential drivers of SOM turnover. The here documented concerted patterns in above-and belowground ecosystem functioning is strongly supportive of using plant community characteristics as surrogates for assessing tundra carbon storage potential and its evolution under climate and vegetation changes.