Above- and belowground linkages in Sphagnum peatland: climate warming affects plant-microbial interactions
Above- and belowground linkages in Sphagnum peatland: climate warming affects plant-microbial interactions
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DOI：
10.1111/gcb.12075
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发表时间：
2013-03-01
影响因子：
11.6
通讯作者：
Gilbert, Daniel
中科院分区：
文献类型：
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作者：
Jassey, Vincent E. J.;Chiapusio, Genevieve;Gilbert, Daniel
泥炭地含有大约三分之一的土壤有机碳(SOC)。气候变暖可以改变泥炭地调节土壤有机碳动态和碳平衡的地上和地下联系。在这里，我们用土壤化学研究了现场实验变暖对微生物食物网、植被及其反馈的多年影响。我们提供了气候变暖对特定微生物功能群产生积极和消极影响的证据，从而导致微生物食物网的不稳定。我们观察到，在变暖的地块中，顶端捕食者(变形虫)的生物量大幅减少(70%)。这样的损失导致微生物食物链缩短，进而刺激微生物活动，导致水中营养物质和不稳定碳水平略有增加。我们进一步表明，气候变暖改变了泥炭藓多酚对微生物群落结构的调节作用，对顶级捕食者有潜在的抑制作用。此外，气候变暖导致泥炭藓盖度减少，维管植物盖度增加。利用结构方程模型，我们发现微生物食物网的变化影响了植物、土壤水化学和微生物群落之间的关系。这些结果表明，气候变暖将通过改变地上和地下的连接来破坏泥炭地碳和养分循环的稳定，因此，与苔藓相关的微生物食物网将通过破坏碳循环对全球变暖做出积极的反馈。这项研究证实，微生物食物网因此构成了泥炭地生态系统功能的关键要素。他们的研究有助于理解，作为生态系统工程师，苔藓如何严格控制泥炭地的生物地球化学循环和气候反馈
Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top-predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum-polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above- and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands