末次冰期南海南部暴露的巽他陆架是大气碳汇?

The Sunda Shelf—A carbon sink during the last glacial period?

在约10万年的冰期-间冰期旋回中,大气CO_2浓度与温度存在几乎同步的周期性变化:间冰期的CO_2浓度约为280×10^(-6),冰期逐渐下降,至盛冰期达到最低(约180×10^(-6)),冰消期又快速回升。关于冰期大气CO_2的去向,前人的许多研究表明,冰期的海洋是个巨大的碳汇,而陆地碳储量在冰期是下降的。从海洋和陆地碳库整体的变化来看,似乎冰期大气CO_2浓度的下降完全可以用海洋碳库的增加来解释,甚至陆地碳库还是大气的源。但通过分析各种地质证据与数值模拟结果,发现末次冰期南海南部暴露的巽他陆架上分布着广阔的热带森林,这意味着,末次冰期暴露的巽他陆架可能具有较强的储碳能力,与冰期陆地的碳源角色相反。因此,为更准确了解碳循环与气候变化,未来的研究需要对陆地碳库进行有效细分,定量描述各区域在碳循环中的角色。

So far,the ice cores from Antarctica have provided a high-resolution record of atmospheric CO_2concentration levels over the past 800000 years.A significant fact is that the atmospheric CO_2concentration variation with respect to change in temperature is almost synchronous throughout these eight glacial-interglacial cycles,ranging from about 180×10^（-6 ）to 280×10^（-6）.While the terrestrial carbon pool is the source of atmospheric CO_2,the deep ocean acts as the sink of the atmospheric CO_（2 ）which could explain the reduction of atmospheric CO_2concentration during the glacial period.However,lots of palynological and numerical simulated evidences reveal that tropical forest must have dominated the emerged Sunda Shelf in the South China Sea during the last glacial period（LGP）,suggesting that the Sunda shelf may have played a role as an atmospheric carbon sink in the LGP.In order to better understand the carbon cycle and climate change,future research needs to subdivide the terrestrial carbon pool effectively with quantitative calculation.