Peak glacial 14 C ventilation ages suggest major draw-down of carbon into the abyssal ocean
Peak glacial 14 C ventilation ages suggest major draw-down of carbon into the abyssal ocean
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DOI：
10.5194/cp-9-2595-2013
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发表时间：
2013-11
影响因子：
4.3
通讯作者：
M. Sarnthein;B. Schneider;P. Grootes
中科院分区：
文献类型：
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作者：
M. Sarnthein;B. Schneider;P. Grootes
抽象的。冰芯记录表明，冰川-间冰期大气CO2增加约100 ppm，而14 C校准工作记录了这一时期大气14 C浓度的大幅下降。计算出的~ 530 Gt的14 C-贫化碳的转移需要产生大气和陆地生物圈中碳的冰消期同期上升。这一数量通常归因于海洋碳释放，尽管实际机制仍然难以捉摸，因为似乎不太可能存在足够古老和富含碳的深海储层。在这里，我们提出了一个新的，虽然仍然零碎，海洋范围内的Δ 14 C数据集显示，在末次盛冰期（LGM）和海因里希Stadial 1（HS-1）之间的最大14 C年龄差异海洋深层沃茨和大气超过现代值高达1500 14 C年，在极端情况下达到5100 14 C年。现代海洋沃茨在2000 m深度以下的14 C通气年龄与溶解无机碳（DIC）的浓度直接相关。我们提出了一个工作假设，即DIC与Δ 14 C的现代回归也适用于LGM时间，这意味着LGM平均年龄约为600 14 C年，对应于深海中约85-115 μmol DIC kg−1的全球上升。因此，海洋深层沃茨停留时间的延长可能确实使其吸收了额外的约730-980 Gt DIC，其中三分之一可能来自中层沃茨。我们还推断，LGM深水O2下降到
Abstract. Ice core records demonstrate a glacial–interglacial atmospheric CO2 increase of ~ 100 ppm, while 14C calibration efforts document a strong decrease in atmospheric 14C concentration during this period. A calculated transfer of ~ 530 Gt of 14C-depleted carbon is required to produce the deglacial coeval rise of carbon in the atmosphere and terrestrial biosphere. This amount is usually ascribed to oceanic carbon release, although the actual mechanisms remained elusive, since an adequately old and carbon-enriched deep-ocean reservoir seemed unlikely. Here we present a new, though still fragmentary, ocean-wide Δ14C data set showing that during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS-1) the maximum 14C age difference between ocean deep waters and the atmosphere exceeded the modern values by up to 1500 14C yr, in the extreme reaching 5100 14C yr. Below 2000 m depth the 14C ventilation age of modern ocean waters is directly linked to the concentration of dissolved inorganic carbon (DIC). We propose as a working hypothesis that the modern regression of DIC vs. Δ14C also applies for LGM times, which implies that a mean LGM aging of ~ 600 14C yr corresponded to a global rise of ~ 85–115 μmol DIC kg−1 in the deep ocean. Thus, the prolonged residence time of ocean deep waters may indeed have made it possible to absorb an additional ~ 730–980 Gt DIC, one third of which possibly originated from intermediate waters. We also infer that LGM deep-water O2 dropped to suboxic values of