Large inert carbon pool in the terrestrial biosphere during the Last Glacial Maximum
Large inert carbon pool in the terrestrial biosphere during the Last Glacial Maximum
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DOI：
10.1038/ngeo1324
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发表时间：
2012-01-01
影响因子：
18.3
通讯作者：
Piao, S. L.
中科院分区：
文献类型：
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作者：
Ciais, P.;Tagliabue, A.;Piao, S. L.
在每一次更新世晚期的冰期-间冰期转变期间，大气中二氧化碳的浓度都会上升近 100 ppm。这些碳的来源尚不清楚，而冰川条件下碳储量和通量的不确定性阻碍了识别碳的努力。在这里，我们使用冰芯中滞留空气的氧同位素测量和海洋碳循环模型来估计末次盛冰期期间陆地和海洋的总初级生产力。我们发现，末次盛冰期期间陆地初级生产力约为 40 +/- 10 Pg C yr(-1)，是工业化前全新世的一半。尽管光合作用水平较低，但我们估计晚冰期陆地生物圈的碳含量仅比工业化前水平少 330 Pg。我们推断，在末次盛冰期，富含碳但生产力低下的生物群落（例如苔原和寒冷草原）覆盖的面积明显更大，这与古生态学数据一致。我们的数据还表明存在 2,300 Pg C 的惰性碳库，比当今永久冻土中锁定的惰性碳多约 700 Pg。我们认为，末次盛冰期末期碳库的消失可能导致了冰消期大气中二氧化碳浓度的上升。
During each of the late Pleistocene glacial-interglacial transitions, atmospheric carbon dioxide concentrations rose by almost 100 ppm. The sources of this carbon are unclear, and efforts to identify them are hampered by uncertainties in the magnitude of carbon reservoirs and fluxes under glacial conditions. Here we use oxygen isotope measurements from air trapped in ice cores and ocean carbon-cycle modelling to estimate terrestrial and oceanic gross primary productivity during the Last Glacial Maximum. We find that the rate of gross terrestrial primary production during the Last Glacial Maximum was about 40 +/- 10 Pg C yr(-1), half that of the pre-industrial Holocene. Despite the low levels of photosynthesis, we estimate that the late glacial terrestrial biosphere contained only 330 Pg less carbon than pre-industrial levels. We infer that the area covered by carbon-rich but unproductive biomes such as tundra and cold steppes was significantly larger during the Last Glacial Maximum, consistent with palaeoecological data. Our data also indicate the presence of an inert carbon pool of 2,300 Pg C, about 700 Pg larger than the inert carbon locked in permafrost today. We suggest that the disappearance of this carbon pool at the end of the Last Glacial Maximum may have contributed to the deglacial rise in atmospheric carbon dioxide concentrations.