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DOI | 10.1073/pnas.1703604114 |
Catalysis and chemical mechanisms of calcite dissolution in seawater | |
Subhas, Adam V.1; Adkins, Jess F.1; Rollins, Nick E.2; Naviaux, John1; Erez, Jonathan3; Berelson, William M.2 | |
2017-08-01 | |
发表期刊 | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA |
ISSN | 0027-8424 |
出版年 | 2017 |
卷号 | 114期号:31页码:8175-8180 |
文章类型 | Article |
语种 | 英语 |
国家 | USA; Israel |
英文摘要 | Near-equilibrium calcite dissolution in seawater contributes significantly to the regulation of atmospheric CO2 on 1,000-y timescales. Despite many studies on far-from-equilibrium dissolution, little is known about the detailed mechanisms responsible for calcite dissolution in seawater. In this paper, we dissolve C-13-labeled calcites in natural seawater. We show that the time-evolving enrichment of delta C-13 in solution is a direct measure of both dissolution and precipitation reactions across a large range of saturation states. Secondary Ion Mass Spectrometer profiles into the C-13-labeled solids confirm the presence of precipitated material even in undersaturated conditions. The close balance of precipitation and dissolution near equilibrium can alter the chemical composition of calcite deeper than one monolayer into the crystal. This balance of dissolution-precipitation shifts significantly toward a dissolution-dominated mechanism below about Omega = 0.7. Finally, we show that the enzyme carbonic anhydrase (CA) increases the dissolution rate across all saturation states, and the effect is most pronounced close to equilibrium. This finding suggests that the rate of hydration of CO2 is a rate-limiting step for calcite dissolution in seawater. We then interpret our dissolution data in a framework that incorporates both solution chemistry and geometric constraints on the calcite solid. Near equilibrium, this framework demonstrates a lowered free energy barrier at the solid-solution interface in the presence of CA. This framework also indicates a significant change in dissolution mechanism at Omega = 0.7, which we interpret as the onset of homogeneous etch pit nucleation. |
英文关键词 | mineral dissolution isotope geochemistry oceanography catalysis |
领域 | 地球科学 ; 气候变化 ; 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000406653300037 |
WOS关键词 | SATURATION STATE ; CARBONATE DISSOLUTION ; TOTAL PRESSURE ; FREE-ENERGY ; DEEP-OCEAN ; KINETICS ; RATES ; TEMPERATURE ; GROWTH ; SEA |
WOS类目 | Multidisciplinary Sciences |
WOS研究方向 | Science & Technology - Other Topics |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/204757 |
专题 | 地球科学 资源环境科学 气候变化 |
作者单位 | 1.CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA; 2.Univ Southern Calif Los Angeles, Dept Earth Sci, Los Angeles, CA 90089 USA; 3.Hebrew Univ Jerusalem, Inst Earth Sci, IL-9190401 Jerusalem, Israel |
推荐引用方式 GB/T 7714 | Subhas, Adam V.,Adkins, Jess F.,Rollins, Nick E.,et al. Catalysis and chemical mechanisms of calcite dissolution in seawater[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2017,114(31):8175-8180. |
APA | Subhas, Adam V.,Adkins, Jess F.,Rollins, Nick E.,Naviaux, John,Erez, Jonathan,&Berelson, William M..(2017).Catalysis and chemical mechanisms of calcite dissolution in seawater.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,114(31),8175-8180. |
MLA | Subhas, Adam V.,et al."Catalysis and chemical mechanisms of calcite dissolution in seawater".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 114.31(2017):8175-8180. |
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