Orbital- and millennial-scale changes of radiolarian assemblages during the last 220 kyrs in the Japan Sea
Orbital- and millennial-scale changes of radiolarian assemblages during the last 220 kyrs in the Japan Sea
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DOI：
10.1016/j.palaeo.2006.11.025
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发表时间：
2007-04
期刊：
影响因子：
--
通讯作者：
T. Itaki;Nozomi Komatsu;I. Motoyama
中科院分区：
文献类型：
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作者：
T. Itaki;Nozomi Komatsu;I. Motoyama
本文报道了日本海三个沉积柱样中7种放射虫在过去220 kyr的显著丰度变化。在间冰期，温暖的水物种（Tetrapyle octacantha组）和温暖/高营养水物种（Lithomelissa setosa）普遍存在，这可能表明对马暖流的流入。另一方面，冷水物种，如Ceratospyris borealis和Stylochlamydium venustum占主导地位的组合在冰川时期，当日本海主要是从邻近的海域，由于较低的海平面。然而，在极盛冰期，S。venustum是强烈的限制，由于低盐度的表面沃茨。深水物种Cycladophora davisiana的丰度似乎发生了重大变化，可能与氧气和有机物质侵入更深的沃茨有关。在MIS-1、MIS-3和MIS-5c中，该物种丰度较高，这是由于深水环境通风良好和有机通量较高所致，而在极盛冰期和MIS-5e中，该物种丰度较低，这可能是由于深水环境缺氧所致。C. davisiana丰度在丹斯加德-厄施格尔旋回的冰阶间期到冰阶期的过渡期显示出高丰度。日本丽癌和刚毛双眉藻的消失事件分别发生在54 ka和85 ka。日本海的这两个事件都可以与北太平洋、白令海和鄂霍次克海的事件联系起来。
Significant abundance changes of seven radiolarian species during the last 220 kyrs in the Japan Sea are reported herein based on three sediment cores. During the interglacial periods, warm water species (the Tetrapyle octacantha group) and warmer/high nutrient water species (Lithomelissa setosa) occurred commonly, which may indicate inflows of the Tsushima Warm Current. On the other hand, cold-water species such as Ceratospyris borealis and Stylochlamydium venustum dominated the assemblage during the glacial periods, when the Japan Sea was mostly isolated from the adjacent seas due to lower eustatic sea level. However, at glacial maxima, the habitat of S. venustum was strongly limited due to low salinity surface waters. The abundance of the deep-water species Cycladophora davisiana seems to have changed significantly, possibly related to the intrusion of oxygen and organic materials into deeper waters. Higher abundances of this species in MIS (marine isotope stage)-1, MIS-3 and MIS-5c resulted from well-ventilated deep water and high organic flux, while its low abundance during the glacial maxima and MIS-5e was probably caused by oxygen-poor deep-water. Millennial-scale variations of C. davisiana abundance show high abundance at the transition intervals from interstadial to stadial periods of the Dansgaard-Oeschger Cycles. The disappearance events of Lychnocanoma nipponica sakaii and Amphimelissa setosa were recognized at 54 ka and 85 ka, respectively. Both of these events in the Japan Sea can be correlated with those in the North Pacific, Bering Sea and Sea of Okhotsk.