Coccolithus pelagicus, a productivity proxy related to moderate fronts off Western Iberia
Coccolithus pelagicus, a productivity proxy related to moderate fronts off Western Iberia
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DOI：
10.1016/s0377-8398(00)00018-9
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发表时间：
2000-06-01
影响因子：
1.9
通讯作者：
Moita, MT
中科院分区：
文献类型：
--
作者：
Cachao, M;Moita, MT
根据其在葡萄牙海岸外水柱中的分布模式(使用11个航次的数据)以及在同一地区全新世表层沉积物样品和第四纪岩心中的分布模式，对作为冷水替代物的传统解释进行了检验。在葡萄牙上升流系统中，椰子藻很常见，该地区的地表水主要来自亚热带。虽然显示出对低温上升水的亲和力，但这种物种在高达18摄氏度的水域中被发现，与河水羽流和陆架断裂锋面有关。在其他浮游藻类群之间，与中等湍流条件和营养物质的可用性有关的是，鹈鹕似乎一直占据着一个特定的生态位。根据这一行为，提出了短尾藻可以作为生产力增强区外围的示踪剂。短尾藻对中等温度和盐度梯度锋面的偏好被试探性地用来解释其沉积记录的特殊特征。在葡萄牙陆架三个河口附近的死海(表层沉积物组合)中不断增加的水华微囊藻被解释为对河流羽流发展的积极响应。另一方面，海面冷冰期和暖间冰期之间的相关性与晚第四纪在加利西亚浅滩两个活塞芯(北纬42度)中记录的鹈鹕的相对丰度模式之间的不一致，被初步解释为伊比利亚半岛外当地古生产力带外部界限的移动。(C)2000 Elsevier Science B.V.保留所有权利。
The traditional interpretation of Coccolithus pelagicus as a cold water proxy is examined based on its distribution patterns in the water column off the Portuguese coast (using data from eleven cruises) and in Holocene surface sediment samples and Quaternary cores from the same region.Coccolithus pelagicus is common in the Portuguese upwelling system, an area where surface waters are predominantly of subtropical origin. Although revealing an affinity for low temperature upwelled waters, the species was found in waters up to 18 degrees C associated with riverine plume and shelf-break fronts. C. pelagicus seemed to consistently occupy a particular ecological niche, between other phytoplankton groups, related to moderate turbulence conditions combined with nutrient availability. From this behaviour, it is proposed that C. pelagicus can be used as a tracer of the periphery of areas of enhanced productivity.Coccolithus pelagicus preferences for fronts of moderate temperature and salinity gradients are tentatively used to explain particular features of its sedimentary record. The repeated increase of C. pelagicus in thanatocoenoses (surface sediment assemblages) close to three river mouths, on the Portuguese shelf are interpreted as a positive response to the development of riverine plumes. On the other hand, inconsistencies in the correlation between sea surface cooler-glacial and warmer-interglacial isotope stages and the relative abundance pattern of C. pelagicus during the Late Quaternary, as registered in two Galicia Bank piston cores (42 degrees N), are tentatively explained in terms of shifts in the extent of the outer limit of the local palaeoproductivity belt off the Iberian Peninsula. (C) 2000 Elsevier Science B.V. All rights reserved.