High-resolution paleoproductivity fluctuations during the past 24 kyr as indicated by benthic foraminifera in the marginal Arctic Ocean
High-resolution paleoproductivity fluctuations during the past 24 kyr as indicated by benthic foraminifera in the marginal Arctic Ocean
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北冰洋边缘的底栖有孔虫表明过去 24 公里的高分辨率古生产力波动
DOI：
10.1016/s0031-0182(03)00726-0
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
A. Mackensen
中科院分区：
文献类型：
--
作者：
J. Wollenburg;J. Knies;A. Mackensen
在末次冰盛期冰盖边缘附近的耶尔马克高原和巴伦支海斜坡约1000m水深的沉积岩芯中，对海底有孔虫的分析表明，在冰川高峰期，古生产力下降到现在水平的三分之一左右。这些减少的数值仍然高于现代永久冰盖地区的数值，这表明即使在体育场馆期间，核心位置至少部分是无冰的。在最初的冰川消融和暖亚阶段，核心区的古生产力高于或等于今天。浮游有孔虫的氧同位素值表明，古生产力的峰值出现在低盐度表层水域的样品中，并略有增加，这表明来自大西洋的温暖海水的增强平流支持了最初的冰盖消退。在全新世期间，耶尔马克高原的气候最佳生产力比现在低得多，巴伦支海地区的生产力很高，这可能是因为大西洋水向巴伦支海地区平流的增加和前者更厚的冰覆盖。在这个最佳时期之后，两个地点的古生产力是相似的，在小冰期等寒冷时期略低一些。
Analyses of benthic foraminifera in sediment cores taken at about 1000 m water depth at the Yermak Plateau and the Barents Sea slope, adjacent to the position of the ice-sheet edge during the Last Glacial Maximum, show that paleoproductivity was reduced to about a third of its present level during peak glacial stadials. These reduced values are still higher than values for modern, permanently ice-covered regions, suggesting that the core locations were at least partially ice-free even during stadials. Paleoproductivity at the core locations was higher than or equal to that of today during initial deglaciations and warm substages. Peak paleoproductivity occurred in samples with low-salinity surface waters as indicated by oxygen isotope values of planktonic foraminifera, and slightly after increased abundance of ‘Atlantic species’, suggesting that enhanced advection of warmer waters from the Atlantic supported the initial ice-sheet retreat. During the Holocene Climatic Optimum productivity was much less than at present on the Yermak Plateau, high at the Barents Sea site, perhaps because of increased advection of Atlantic water to the latter site and heavier ice coverage at the former. After this optimum, paleoproductivity at both sites was similar, with slightly lower values during cold periods such as the Little Ice Age.