Bell Robin E, Studinger Michael, Tikku Anahita A, Clarke Garry K C, Gutner Michael M, Meertens Chuck
Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA.
Nature. 2002 Mar 21;416(6878):307-10. doi: 10.1038/416307a.
The subglacial Lake Vostok may be a unique reservoir of genetic material and it may contain organisms with distinct adaptations, but it has yet to be explored directly. The lake and the overlying ice sheet are closely linked, as the ice-sheet thickness drives the lake circulation, while melting and freezing at the ice-sheet base will control the flux of water, biota and sediment through the lake. Here we present a reconstruction of the ice flow trajectories for the Vostok core site, using ice-penetrating radar data and Global Positioning System (GPS) measurements of surface ice velocity. We find that the ice sheet has a significant along-lake flow component, persistent since the Last Glacial Maximum. The rates at which ice is frozen (accreted) to the base of the ice sheet are greatest at the shorelines, and the accreted ice layer is subsequently transported out of the lake. Using these new flow field and velocity measurements, we estimate the time for ice to traverse Lake Vostok to be 16,000-20,000 years. We infer that most Vostok ice analysed to date was accreted to the ice sheet close to the western shoreline, and is therefore not representative of open lake conditions. From the amount of accreted lake water we estimate to be exported along the southern shoreline, the lake water residence time is about 13,300 years.
沃斯托克冰下湖可能是一个独特的基因物质储存库，可能包含具有独特适应性的生物，但尚未得到直接探索。该湖与上覆冰盖紧密相连，因为冰盖厚度驱动湖水循环，而冰盖底部的融化和冻结将控制水、生物群和沉积物通过湖泊的通量。在这里，我们利用探地雷达数据和全球定位系统（GPS）对地表冰速的测量，重建了沃斯托克冰芯站点的冰流轨迹。我们发现，自末次盛冰期以来，冰盖一直存在显著的沿湖流动分量。在海岸线处，冰冻结（堆积）到冰盖底部的速率最大，随后堆积的冰层被带出湖泊。利用这些新的流场和速度测量数据，我们估计冰穿过沃斯托克湖的时间为16000 - 20000年。我们推断，迄今为止分析的大多数沃斯托克冰是在靠近西岸线的地方堆积到冰盖上的，因此不能代表开阔湖的情况。根据我们估计沿南岸线输出的堆积湖水数量，湖水停留时间约为13300年。
