Biogeochemical cycling in the Bering Sea over the onset of major Northern Hemisphere Glaciation
Biogeochemical cycling in the Bering Sea over the onset of major Northern Hemisphere Glaciation
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DOI：
10.1002/2016pa002978
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
George E. A. Swann;A. Snelling;A. Snelling;J. Pike
中科院分区：
文献类型：
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作者：
George E. A. Swann;A. Snelling;A. Snelling;J. Pike
白令海是海洋系统中最具生物生产力的区域之一，在调节流向北冰洋和亚北极北太平洋的沃茨方面发挥着关键作用。从IODP远征323到白令海的岩心提供了第一次机会，以获得从该地区延伸到上新世的重建。先前在白令海南部鲍尔斯海岭的研究表明，在北方半球主要冰期（NHG）开始时，硅质生产力水平稳定（c。2.85-2.73 Ma）。然而，硅藻硅氧同位素记录（δ 18 Odiatom）和硅（δ 30 Sidiatom）在这里提出的证明，这段时间是与逐步增加的供应，在该地区的柠檬酸，叠加上转移到一个更动态的环境，其特征是更冷的温度和海冰增加。这一结论在2.58马与硅藻生产力的急剧增加，进一步增加透光区营养物质的可用性和永久转移到较冷的海面条件。这些过渡建议，以反映逐渐更强烈的营养物质从亚北极西北太平洋泄漏，增加生产力的进一步帮助增加海冰和风驱动的混合在白令海。在建议的联系，在南白令海和亚北极西北太平洋之间的地球化学循环，主要通过堪察加海峡，这项工作突出了需要考虑这两个系统的相互连接，当未来的重建在该地区进行。
The Bering Sea is one of the most biologically productive regions in the marine system and plays a key role in regulating the flow of waters to the Arctic Ocean and into the subarctic North Pacific Ocean. Cores from IODP Expedition 323 to the Bering Sea provide the first opportunity to obtain reconstructions from the region that extend back to the Pliocene. Previous research at Bowers Ridge, south Bering Sea, has revealed stable levels of siliceous productivity over the onset of major Northern Hemisphere Glaciation (NHG) (c. 2.85-2.73 Ma). However, diatom silica isotope records of oxygen (δ18Odiatom) and silicon (δ30Sidiatom) presented here demonstrate that this interval was associated with a progressive increase in the supply of silicic acid to the region, superimposed on shift to a more dynamic environment characterized by colder temperatures and increased sea ice. This concluded at 2.58 Ma with a sharp increase in diatom productivity, further increases in photic zone nutrient availability and a permanent shift to colder sea surface conditions. These transitions are suggested to reflect a gradually more intense nutrient leakage from the subarctic northwest Pacific Ocean, with increases in productivity further aided by increased sea-ice and wind-driven mixing in the Bering Sea. In suggesting a linkage in biogeochemical cycling between the south Bering Sea and subarctic Northwest Pacific Ocean, mainly via the Kamchatka Strait, this work highlights the need to consider the inter-connectivity of these two systems when future reconstructions are carried out in the region.