Distribution of large Emiliania huxleyi in the Central and Northeast Atlantic as a tracer of surface ocean dynamics during the last 25,000 years
Distribution of large Emiliania huxleyi in the Central and Northeast Atlantic as a tracer of surface ocean dynamics during the last 25,000 years
复制标题
DOI：
10.1016/j.marmicro.2010.05.001
复制
发表时间：
2010-09-01
影响因子：
1.9
通讯作者：
Rodrigues, Teresa
中科院分区：
文献类型：
--
作者：
Flores, Jose-Abel;Colmenero-Hidalgo, Elena;Rodrigues, Teresa
颗石藻物种 Emiliania huxleyi 的特点是尺寸范围广泛。在光学显微镜下很容易区分。在这项研究中，我们对过去 25 年前来自大西洋东北部和地中海西部 11 个岩心和钻探点的沉积记录中大型（最大长度 >4 微米的颗石石）E. huxleyi 标本的丰度进行了量化，以证明其在重建水体动力学和生物地层潜力方面的有用性。 指标，在大西洋东北部和地中海很常见，其丰度的区域变化表明气候带向南移动，与这一时期北半球冰盖和海冰的发展一致。另一方面，副热带环流南北表面水团之间的梯度似乎比现在更加明显，而葡萄牙洋流和加那利洋流则更加强烈。西地中海盆地的温度比邻近的大西洋要低，导致这些标本在海因里希事件1结束之前成为准特有现象。这可能是由于大西洋和地中海之间通过直布罗陀海峡的交通受到限制、寒冷的地表水的到来以及北部冰盖发展后冷却的放大所致。 半球。在冰消期期间，中低纬度地区的大型赫胥黎石斑鱼标本数量减少，但在全新世期间靠近亚北极地区的数量仍然很多。在过渡水域中，这种丰度下降到现在的丰度是在 lb 终止之后发生的。 这种大型赫胥黎 E. huxleyi 形式丰度的突然变化被认为是一个新的生物地层事件，以表征北大西洋中低纬度水团的全新世特征，尽管这一地平线似乎从热带到亚北极地区穿时了 5 kyr，这与温暖条件的逐渐开始一致。 (C) 2010 Elsevier B.V. 保留所有权利。
The coccolithophore species Emiliania huxleyi is characterized by a wide range of sizes. which can be easily distinguished in the light microscope. In this study we have quantified the abundance of large (coccoliths >4 mu m in maximum length) E. huxleyi specimens during the last 25 kyr in sedimentary records from eleven cores and drill sites in the NE Atlantic and W Mediterranean Sea, to prove its usefulness in the reconstruction of water mass dynamics and biostratigraphic potential.During the Last Glacial Maximum this large form, a cold-water indicator, was common in the NE Atlantic and Mediterranean, and its regional variation in abundance indicates a displacement of the climatic zones southwards in agreement with the development of ice sheets and sea ice in the Northern Hemisphere during this period. On the other hand, the gradient between northern and southern surface water masses in the Subtropical Gyre appears to have been more pronounced than at present, while the Portugal and Canary Currents were more intense. In the western Mediterranean basin temperatures were cooler than in the adjacent Atlantic, provoking a quasi-endemism of these specimens until the end of Heinrich Event 1. This may have been due to a restriction in the communication between the Atlantic and Mediterranean through the Strait of Gibraltar, the arrival of cold surface water and the amplification of cooling after the development of ice sheets in the Northern Hemisphere.During the deglaciation, large E. huxleyi specimens decreased in abundance at medium and low latitudes, but were still numerous close to the Subarctic region during the Holocene. In transitional waters this decrease to present day abundances occurred after Termination lb.The abrupt change in abundance of this large E. huxleyi form is proposed as a new biostratigraphic event to characterize the Holocene in mid- to low-latitude water masses in the North Atlantic, although this horizon seems to be diachronous by 5 kyr from tropical to subarctic regions, in agreement with the gradual onset of warm conditions. (C) 2010 Elsevier B.V. All rights reserved.