Carbonate ion concentration in glacial‐age deep waters of the Caribbean Sea
Carbonate ion concentration in glacial‐age deep waters of the Caribbean Sea
复制标题
加勒比海冰期深水中的碳酸根离子浓度
DOI：
10.1029/2001gc000231
复制
发表时间：
2002
期刊：
影响因子：
3.7
通讯作者：
E. Clark
中科院分区：
文献类型：
--
作者：
W. Broecker;E. Clark
根据来自加勒比海核心的 G. sacculifer 和 N. dutertrei 的整个有孔虫壳重量，看来在开放大西洋 1800 m 深度（即加勒比海床的深度）的水中碳酸根离子浓度在冰期期间比全新世期间高约 14 μmol/kg。这种差异的感觉与冰期大西洋上层深水中底栖有孔虫的 13C/12C 比值高于全新世同类的观察结果一致。它也与片段到整个有孔虫结果一致。然而，由于有关将贝壳重量转换为古碳酸盐离子浓度的假设的几个问题仍未得到解答，因此这种重建必须被认为是暂时的。在这方面至关重要的假设是，冰期期间任何给定地点的贝壳壁厚度与今天相同，并且贝壳重量与碳酸根离子浓度之间的 0.3 μg/μmol/kg 关系适用于整个深水柱。这里报告的记录没有显示任何全新世早期保存事件的证据。然而，岩心 V28-122 记录了接近 MIS 5-4 边界的溶解事件。
On the basis of the whole foraminifera shell weights for G. sacculifer and N. dutertrei from Caribbean cores, it appears that the carbonate ion concentration of water at 1800 m depth in the open Atlantic (i.e., the depth of the Caribbean sill) was ∼14 μmol/kg greater during glacial time than during the Holocene. The sense of this difference is consistent with the observation that the 13C/12C ratio for benthic foraminifera from glacial‐age Atlantic upper deep water was higher than that for their Holocene equivalents. It is also consistent with fragment to whole foraminifera results. However, as several questions regarding the assumptions involved in converting shell weights to paleocarbonate ion concentrations remain unanswered, this reconstruction must be considered tentative. Critical in this regard are the assumptions that shell‐wall thicknesses were the same as today's at any given site during glacial time and that the 0.3 μg per μmol/kg relationship between shell weight and carbonate ion concentration is applicable over the entire deep water column. The records reported here reveal no evidence for an early Holocene preservation event. However, that for core V28‐122 documents a dissolution event close to the MIS 5‐4 boundary.