Warming of subarctic tundra increases emissions of all three important greenhouse gases – carbon dioxide, methane, and nitrous oxide
Warming of subarctic tundra increases emissions of all three important greenhouse gases – carbon dioxide, methane, and nitrous oxide
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亚北极苔原的变暖增加了三种重要温室气体的排放--二氧化碳、甲烷和一氧化二氮
DOI：
10.1111/gcb.13563
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发表时间：
2017-08
影响因子：
11.6
通讯作者：
C. Voigt;R. E. Lamprecht;M. Marushchak;S. Lind;A. Novakovskiy;M. Aurela;P. Martikainen;C. Biasi
中科院分区：
文献类型：
--
作者：
C. Voigt;R. E. Lamprecht;M. Marushchak;S. Lind;A. Novakovskiy;M. Aurela;P. Martikainen;C. Biasi
北极气温的迅速上升可能会导致更多的温室气体释放到大气中。为了研究气候变暖对温室气体动力学的影响，我们在俄罗斯东北部欧洲的亚北极苔原地区部署了开顶室。我们确定了二氧化碳（CO2），甲烷（CH 4），一氧化二氮（N2 O）通量以及这些气体的浓度，无机氮（N）和溶解有机碳（DOC）沿着土壤剖面。研究苔原表面的范围从矿物有机土壤和从植被到无植被的地区。由于空气变暖，苔原植被表面的季节性温室气体收支从-300至-198克CO2当量m−2的温室气体汇转变为105至144克CO2当量m−2的温室气体源。在裸露的泥炭表面，我们观察到所有三种温室气体的释放增加。虽然积极的变暖反应主要是由CO2，我们在这里提供的第一个原位证据增加N2 O排放量从冻土带土壤变暖。气候变暖促进了N2 O的释放，不仅从裸露的泥炭，以前确定为一个强大的N2 O源，但也从丰富的，植被泥炭表面，不排放N2 O在目前的气候。在这些表面上，温度升高对植物生长产生不利影响，导致植物氮素吸收降低，因此，土壤微生物的氮素可用性更好。虽然变暖仅限于土壤表面，并没有改变解冻深度，它增加了DOC，CO2和CH 4的浓度在土壤中的冻土表。这可以归因于向下的DOC淋溶，在深度处助长了微生物活动。总之，我们的研究结果强调了植物和土壤过程之间的紧密联系，以及不同的土壤层，这需要考虑到在预测北极的气候变化反馈。
Rapidly rising temperatures in the Arctic might cause a greater release of greenhouse gases (GHGs) to the atmosphere. To study the effect of warming on GHG dynamics, we deployed open‐top chambers in a subarctic tundra site in Northeast European Russia. We determined carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes as well as the concentration of those gases, inorganic nitrogen (N) and dissolved organic carbon (DOC) along the soil profile. Studied tundra surfaces ranged from mineral to organic soils and from vegetated to unvegetated areas. As a result of air warming, the seasonal GHG budget of the vegetated tundra surfaces shifted from a GHG sink of −300 to −198 g CO2–eq m−2 to a source of 105 to 144 g CO2–eq m−2. At bare peat surfaces, we observed increased release of all three GHGs. While the positive warming response was dominated by CO2, we provide here the first in situ evidence of increasing N2O emissions from tundra soils with warming. Warming promoted N2O release not only from bare peat, previously identified as a strong N2O source, but also from the abundant, vegetated peat surfaces that do not emit N2O under present climate. At these surfaces, elevated temperatures had an adverse effect on plant growth, resulting in lower plant N uptake and, consequently, better N availability for soil microbes. Although the warming was limited to the soil surface and did not alter thaw depth, it increased concentrations of DOC, CO2, and CH4 in the soil down to the permafrost table. This can be attributed to downward DOC leaching, fueling microbial activity at depth. Taken together, our results emphasize the tight linkages between plant and soil processes, and different soil layers, which need to be taken into account when predicting the climate change feedback of the Arctic.