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首页> 外文期刊>Nature >Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles.
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Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles.

机译：过去八个冰川周期中，南大洋海冰的范围，生产力和铁通量。

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摘要

Sea ice and dust flux increased greatly in the Southern Ocean during the last glacial period. Palaeorecords provide contradictory evidence about marine productivity in this region, but beyond one glacial cycle, data were sparse. Here we present continuous chemical proxy data spanning the last eight glacial cycles (740,000 years) from the Dome C Antarctic ice core. These data constrain winter sea-ice extent in the Indian Ocean, Southern Ocean biogenic productivity and Patagonian climatic conditions. We found that maximum sea-ice extent is closely tied to Antarctic temperature on multi-millennial timescales, but less so on shorter timescales. Biological dimethylsulphide emissions south of the polar front seem to have changed little with climate, suggesting that sulphur compounds were not active in climate regulation. We observe large glacial-interglacial contrasts in iron deposition, which we infer reflects strongly changing Patagonian conditions. During glacial terminations, changes in Patagonia apparently preceded sea-ice reduction, indicating that multiple mechanisms may be responsible for different phases of CO2 increase during glacial terminations. We observe no changes in internal climatic feedbacks that could have caused the change in amplitude of Antarctic temperature variations observed 440,000 years ago.
机译：在最后一个冰川期，南大洋的海冰和尘埃通量大大增加。古记录为该地区的海洋生产力提供了相互矛盾的证据，但除了一个冰川周期外，数据稀疏。在这里，我们提供了来自Dome C南极冰芯的最近八个冰川周期（740,000年）的连续化学替代数据。这些数据限制了印度洋的冬季海冰范围，南大洋的生物生产力和巴塔哥尼亚的气候条件。我们发现，在几千年的时间尺度上，最大海冰范围与南极温度密切相关，而在较短的时间尺度上则不那么严重。极地锋以南的生物二甲基硫化物排放似乎没有随气候变化而变化，这表明硫化合物在气候调节中没有活性。我们在铁沉积中观察到较大的冰间差异，我们推断这反映了巴塔哥​​尼亚条件的强烈变化。在冰川终结期间，巴塔哥尼亚的变化显然是在海冰减少之前发生的，这表明在冰川终结期间，CO 2增加的不同阶段可能与多种机制有关。我们没有观察到内部气候反馈的变化会导致440,000年前观测到的南极温度变化幅度的变化。

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