Simple additive simulation overestimates real influence: altered nitrogen and rainfall modulate the effect of warming on soil carbon fluxes
Simple additive simulation overestimates real influence: altered nitrogen and rainfall modulate the effect of warming on soil carbon fluxes
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DOI：
10.1111/gcb.13588
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发表时间：
2017-08
影响因子：
11.6
通讯作者：
X. Ni;Wanqin Yang;Zemin Qi;Shu Liao;Zhen-feng Xu;B. Tan;Bin Wang;Qinggui Wu;Changkun Fu
中科院分区：
文献类型：
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作者：
X. Ni;Wanqin Yang;Zemin Qi;Shu Liao;Zhen-feng Xu;B. Tan;Bin Wang;Qinggui Wu;Changkun Fu
实验和模型导致了一种共识，即碳(C)通量与气候变暖之间存在正反馈。然而，气候变暖的影响可能会被区域和全球氮(N)和降雨量的变化所改变，但目前的理解是有限的。通过综合模拟氮沉降、干旱和降水增加的土壤碳库、输入和损失的全球数据，我们量化了土壤碳通量和平衡对这三个单一因素的响应及其与气候变暖的相互作用。结果表明，增温使土壤碳输入和流失分别略微增加了5%和9%，但对土壤碳库没有显著影响。氮沉降单独增加了土壤碳输入(+20%)，但增温和氮沉降的交互作用使土壤碳输入增加了49%。干旱单独作用使土壤碳输入减少了17%，而气候变暖和干旱交互作用对土壤碳输入的影响更大(−为22%)。降水增加使土壤碳输入增加15%，但增温和降水增加的交互作用对土壤碳输入没有显著影响。然而，土壤碳的流失虽然受到干旱的限制(−为18%)，但并未受到任何交互作用的显著影响。这些结果表明，正C通量-气候变暖反馈受到N和降雨制度变化的调制。此外，我们还发现，[增温×N沉降]和[增温×干旱]对土壤C输入的加性效应和[增温×增雨]对土壤C流失的加性效应大于它们之间的交互作用，这表明简单的加性模拟可能高估了真实世界土壤C通量的影响。因此，我们建议在研究地球系统时应考虑更多的多因素实验。
Experiments and models have led to a consensus that there is positive feedback between carbon (C) fluxes and climate warming. However, the effect of warming may be altered by regional and global changes in nitrogen (N) and rainfall levels, but the current understanding is limited. Through synthesizing global data on soil C pool, input and loss from experiments simulating N deposition, drought and increased precipitation, we quantified the responses of soil C fluxes and equilibrium to the three single factors and their interactions with warming. We found that warming slightly increased the soil C input and loss by 5% and 9%, respectively, but had no significant effect on the soil C pool. Nitrogen deposition alone increased the soil C input (+20%), but the interaction of warming and N deposition greatly increased the soil C input by 49%. Drought alone decreased the soil C input by 17%, while the interaction of warming and drought decreased the soil C input to a greater extent (−22%). Increased precipitation stimulated the soil C input by 15%, but the interaction of warming and increased precipitation had no significant effect on the soil C input. However, the soil C loss was not significantly affected by any of the interactions, although it was constrained by drought (−18%). These results implied that the positive C fluxes–climate warming feedback was modulated by the changing N and rainfall regimes. Further, we found that the additive effects of [warming × N deposition] and [warming × drought] on the soil C input and of [warming × increased precipitation] on the soil C loss were greater than their interactions, suggesting that simple additive simulation using single‐factor manipulations may overestimate the effects on soil C fluxes in the real world. Therefore, we propose that more multifactorial experiments should be considered in studying Earth systems.