Varying responses to Indian monsoons during the past 220 kyr recorded in deep-sea sediments in inner and outer regions of the Gulf of Aden
Varying responses to Indian monsoons during the past 220 kyr recorded in deep-sea sediments in inner and outer regions of the Gulf of Aden
复制标题
亚丁湾内外深海沉积物记录的过去220 kyr对印度季风的不同响应
DOI：
10.1002/2015jc010982
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Isaji;Y.;Kawahata;H.;Ohkouchi;N.;Ogawa;N. O.;Murayama;M.;Inoue;K.;and Tamaki;K.
虽然阿拉伯海的气候主要受西南季风控制，但西南季风对亚丁湾的影响很小。为了研究亚丁湾和海湾以外地区对季风的不同响应，从海湾内部和外部区域回收的深海沉积物岩心中获得了大量有机和无机地球化学、海面温度和表色素δ 15 N的综合数据集。结果表明，在过去的220 kyr，西南季风的影响是在海湾的外部区域比在内部区域更强，这意味着西南季风的轨迹并没有发生实质性的变化，在这段时间。此外，来自南大洋的贫氧水的流入和上升海水的横向平流也对内部区域产生了有限的影响。相反，浓度的成岩物质输送的西南季风在这两个地区是相似的。δ 15 N值表明，末次盛冰期西南季风较弱，东北季风较强。一个强大的西南季风在间冰期提高初级生产力，并可能造成缺氧条件下发展在阿拉伯海，在外部区域的氧化还原代理所示。在MIS 3期间也形成了缺氧条件，但没有显示初级生产力的增加;因此，另一种机制，例如来自南大洋的贫氧水的涌入，可能是原因。
Although the climate in the Arabian Sea is controlled primarily by the southwest monsoon, the southwest monsoon has little influence in the Gulf of Aden. To examine the different responses to monsoons between the Gulf of Aden and areas outside the gulf, a comprehensive data set of bulk organic and inorganic geochemistry, sea surface temperature, and δ15N of pheopigments was obtained from deep‐sea sediment cores recovered from inner and outer regions of the gulf. The results indicated that during the past 220 kyr, the influence of the southwest monsoon was stronger in the outer region of the gulf than in the inner region, which implies that the southwest monsoon trajectory has not changed substantially during that time period. Furthermore, influxes of O2‐depleted water from the Southern Ocean and the lateral advection of upwelled seawater also had limited influence in the inner region. In contrast, concentrations of lithogenic materials transported by the southwest monsoon were similar in the two regions. δ15N of pheopigments indicated that during the last glacial maximum, the southwest monsoon was weaker and the northeast monsoon was stronger than at present. A stronger southwest monsoon during interglacials enhanced primary productivity and may have caused anoxic conditions to develop in the Arabian Sea, as indicated by redox proxies in the outer region. Anoxic conditions also formed during MIS 3, but no increase in the primary productivity is indicated; therefore, another mechanism, such as an influx of O2‐depleted water from the Southern Ocean, may have been the cause.