Vascular plants promote ancient peatland carbon loss with climate warming.
Vascular plants promote ancient peatland carbon loss with climate warming.
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随着气候变暖，维管束植物会促进泥炭地的碳流失。
DOI：
10.1111/gcb.13213
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发表时间：
2016-05
影响因子：
11.6
通讯作者：
Ostle NJ
中科院分区：
文献类型：
--
作者：
Walker TN;Garnett MH;Ward SE;Oakley S;Bardgett RD;Ostle NJ
北方泥炭地自上一次冰河时代以来积累了地球土壤碳储量的三分之一。北方生物群落的快速变暖有可能加速泥炭地生态系统呼吸的速率。尽管净初级生产力的补偿性增加，但更大的生态系统呼吸可能标志着泥炭地有机质存量中古老的、世纪至千年的碳的释放。气候变暖已经被证明会促进古代泥炭地的碳释放，但是，尽管植被在碳动力学中起着关键作用，但人们对植物如何影响泥炭地生态系统呼吸的来源知之甚少。在这里，我们解决这个问题，使用原位14C测量生态系统呼吸的一个既定的泥炭地变暖和植被操作实验。结果表明，当矮灌木或禾本科植物存在时，约1 °C的变暖促进了古老泥炭地碳（长达2100年）的呼吸，当只有britectes存在时没有观察到这种效果。我们表明，变暖可能会促进古代泥炭地碳释放，通过其控制有机输入维管植物。我们的研究结果表明，矮灌木和禾本科植物促使微生物分解先前“锁定”的有机物，这些有机物可能来自泥炭剖面的深处，促进了古老的碳以二氧化碳的形式释放。此外，这种植物诱导的泥炭呼吸可能占生态系统二氧化碳排放量的40%。如果在其他亚北极和北极生态系统中保持一致，这代表了目前全球碳循环模型尚未承认的生态系统呼吸的相当一部分。最终，古代碳对生态系统呼吸的更大贡献可能标志着以前稳定的泥炭地碳库的丧失，从而对未来的气候变化产生潜在的反馈。
Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century‐ to millennia‐old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ 14C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf‐shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf‐shrubs and graminoids prime microbial decomposition of previously ‘locked‐up’ organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO2. Furthermore, such plant‐induced peat respiration could contribute up to 40% of ecosystem CO2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change.