Holocene palaeoceanographic changes in Barrow Strait, Canadian Arctic: foraminiferal evidence
Holocene palaeoceanographic changes in Barrow Strait, Canadian Arctic: foraminiferal evidence
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DOI：
10.1002/jqs.1367
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发表时间：
2010-09
影响因子：
2.3
通讯作者：
T. R. Gregory;C. Smart;M. Hart;G. Massé;Lindsay L. Vare;S. Belt
中科院分区：
文献类型：
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作者：
T. R. Gregory;C. Smart;M. Hart;G. Massé;Lindsay L. Vare;S. Belt
海洋沉积岩芯(ARC-3加拿大北极群岛，北纬74°16.050‘，西经91°06.380’，水深347m)底栖生物和浮游有孔虫的全新世变化表明，在过去的10ka期间，环境和古海洋发生了显著的变化。有孔虫组合局限于大约4.5-10ka的时间段，因为在大约4.5ka之后，由于碳酸盐的强烈溶解，年轻的样品大多没有有孔虫。在约4.5~10ka的有孔虫组合中，以底栖物种海岛藻和肾型有孔虫为主，占总数的57%，同时还常见棒状石首藻、小叶刺藻和冷角藻。这些物种的优势指示了季节性的海冰状况，这与海冰硅藻衍生的有机地球化学生物标志物IP25在整个岩芯中的出现是一致的。肾形藻类和棒形藻类的丰度在地心上部下降；这与巴罗海峡水柱在全新世早期更频繁的混合一致。这可能是富CO2的北极表层水团的影响导致了约8.5ka以后底层水的腐蚀性增加，而在约6ka之后，伴随着IP25通量的增加，与海冰相关的过程进一步增强了溶解作用。当IP25通量最高时，溶解作用最强，这表明海冰和底栖系统之间存在联系。版权所有©2010 John Wiley&Sons，Ltd.
Holocene changes in the benthic and planktic foraminiferal fauna (>63 µm) from a marine sediment core (ARC‐3 Canadian Arctic Archipelago, 74° 16.050′ N, 91° 06.380′ W, water depth 347 m) show that significant environmental and palaeoceanographic variations occurred during the last 10 ka. Foraminiferal assemblages are restricted to the ca. 4.5–10 ka interval as younger samples are mostly barren of foraminifera due to intense carbonate dissolution after ca. 4.5 ka. Foraminiferal assemblages in the ca. 4.5–10 ka interval are dominated by the benthic species Islandiella helenae and Cassidulina reniforme (57% of total), with Elphidium clavatum, Cibicides lobatulus and Buccella frigida also being common in this interval. The dominance of these species indicates a seasonal sea ice regime which is consistent with the occurrence of the sea ice diatom‐derived organic geochemical biomarker IP25 throughout the core. The abundances of C. reniforme and E. clavatum decline upcore; consistent with more frequent mixing of the Barrow Strait water column during the early Holocene. It is likely that the influence of CO2‐rich Arctic surface water masses have caused an increase in bottom water corrosivity after ca. 8.5 ka, and dissolution has been further enhanced by sea ice‐related processes after ca. 6 ka, concomitant with increased IP25 fluxes. Dissolution is strongest when IP25 fluxes are highest, suggesting a link between the sea ice and benthic systems. Copyright © 2010 John Wiley & Sons, Ltd.