| 碳酸酐酶对碳酸盐岩溶解的催化作用及其在大气CO2沉降中的意义 |
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| 引用本文：刘再华.2001.碳酸酐酶对碳酸盐岩溶解的催化作用及其在大气CO2沉降中的意义[J].地球学报,22(5):477-480. |
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| 基金项目:国家自然科学基金项目(编号:40073026);国土资源部“百人计划”项目(编号9806);广西自然科学基金项目(编号:9824021;德国不莱梅大学博士后研究基金项目;科技部社会公益研究专项资金项目(编号:164) |
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| 中文摘要:CO2向H^ 和HCO3^－的转换是一相对慢速过程。因此，其动力学可能决定碳酸盐岩的溶解速率。在灰岩和白云岩的溶解实验中，使用了自然界普遍存在的碳酸酐酶（CA）来催化这一CO2转换反应，结果发现，对灰岩而言，加入CA后，其溶解速率在高CO2分层时可增加10倍，而对白云岩，其溶解速率增加主要在低CO2分压时，可达3倍左右。这一发现表明，化学风化（包括碳酸盐岩溶解和硅酸盐风化）作用在大气CO2沉降和全球碳循环里的所谓丢失的汇中的重要性需要重新评价。毫无疑问，已往的研究由于未认识到CA在风化中的催化作用，因此低估了风化作用的速率，同时也低估了风化作用对大气CO2沉降的贡献。另一方面，也表明了研究自然界不同水体中CA分布及其活度和CA在自然界风化作用中的作用的必要性。 |
| 中文关键词:碳酸酐酶 CO2转换 碳酸盐岩溶解 化学风化 大气CO2沉降 |
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| The Role of Carbonic Anhydrase as an Activator in Carbonate Rock Dissolution and Its Significance in Atmospheric CO2 Precipitation |
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| Abstract:The conversion of CO 2 into H + and HCO - 3 is a relatively slow reaction. Hence, its kinetics may determine the rate of carbonate rock dissolution. Carbonic anhydrase (CA), which is widespread in nature, was used to catalyze the CO 2 conversion process in dissolution experiments of limestone and dolomite. It is found that the rates of dissolution increase remarkably after the addition of CA, by a factor of 10 or so at high CO 2 partial pressure (P CO 2) for limestone and about 3 at low P CO 2 for dolomite. It is thus held that the importance of chemical weathering (including the carbonate rock dissolution and silicate weathering) in atmospheric CO 2 precipitation and the mysterious missing precipitation in carbon cycling requires reappraisal. Due to the ignorance of CA as an activator in weathering, previous studies of weathering undoubtedly underestimated weathering rates, and hence the contribution of weathering to the atmospheric CO 2 precipitation was also underestimated. This finding also shows the need to examine in situ distribution and activity of CA in different water bodies and to investigate the role of CA in weathering. |
| keywords:carbonic anhydrase CO2 conversion carbonate rock dissolution chemical weathering atmospheric CO2 precipitation |
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