The dissolution kinetics of biogenic calcium carbonates in seawater
The dissolution kinetics of biogenic calcium carbonates in seawater
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DOI：
10.1016/0016-7037(80)90135-0
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发表时间：
1980-02
影响因子：
5
通讯作者：
R. Keir
中科院分区：
文献类型：
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作者：
R. Keir
测定了不同种类的球岩壳和有孔虫壳、安东-爪哇高原和里约热内卢大隆升（一组大型翼足类）沉积物的不同粒度组分以及合成方解石和文石粉的溶蚀速率与欠饱和程度的关系。研究结果表明，所有生物源碳酸钙和合成碳酸钙均遵循速率规律R%= k%（1−Ω） n，其中Ω[ca2 +][co32−]/ k 'sp, k 'sp是方解石或文石海水的表观溶解度产物。对于所有方解石样品，nc = 4.5，而对于文石样品，na = 4.2。“速率常数”k%在不同样品之间变化很大，在许多情况下与晶粒尺寸呈负相关。然而，在实验室中培养的个别种的球粒石，赫胥黎和新helis似乎不遵循这一规律，其溶解速度比预期低一个数量级。
Dissolution rate as a function of degree of undersaturation was measured on shells of individual species of coccoliths and foraminifera, various size fractions of sediment from the Ontong-Java Plateau and the Rio Grande Rise, a collection of large pteropods, and on synthetic calcite and aragonite powder. Results of the study indicate that all biogenic and synthetic calcium carbonate follows the rate law R%= k%(1− Ω) n where Ω[Ca 2+][CO 3 2−]/K'sp and K'sp is the apparent solubility product of calcite or aragonitic seawater. In the case of all calcite samples, n c= 4.5, while for aragonitic samples n a= 4.2. The ‘rate constant’, k%, varies widely between samples and in many cases is inversely correlated with grain size. However, the individual species of coccoliths, E. huxleyi and C. neohelis, which were cultured in the laboratory appear not to follow this rule, with dissolution rates an order to magnitude lower than expected.