对2011年《中国岩溶》第4期文章《中国岩溶作用产生的大气CO2碳汇的分区计算》及其引用和认可的两个重要碳汇数据,就碳汇测定方法原理、参数取值、计算公式和计算结果做了一些讨论.认为,①由于参数取值不妥等原因,北方区计算结果可能偏大3倍以上；因运算有误以及径流模数评估不当,埋藏区岩溶碳汇计算结果可能偏大200多倍；②由于方法原理的固有缺欠,该文所引用的、用定点磨片溶蚀法取得的全球岩溶碳汇通量(6.08×108 tC/a)可能偏大4倍；③所引用数据的原始计算中新提出的主要水循环碳汇项,由于考虑其地球化学产生机制过于简单,各项评估结果都可能偏大20倍以上；结果使给出的全球水循环碳汇净通量(0.6433 GtC/a)偏大2倍多,实际上,比用化学通量法测定的全球碳酸盐风化碳汇值(0.2433±0.05 GtC/a)大不了很多；水生光合碳汇截留量可能不会很大；④使用的化学径流碳汇计算公式,虽是当前国内外通用公式,但因属于只考虑大气/土壤CO2溶蚀的简化公式,需要对非大气/土壤CO2溶蚀做进一步校正；校正后全球岩溶碳汇通量将再减少35％左右；⑤综合分析现有测定结果显示,在有世界大河化学径流记录以来的100多年里,全球岩溶碳汇通量平均大概不会超过0.1士0.02 GtC/a太多；由于其基数太低,即使进行人为干预,也只能是一个局部或附属的大气CO2汇(如附属于局部地区森林生长量的成倍增长)；如果再考虑被碳酸盐风化作用临时吸收的大气CO2,绝大部分最终要因碳酸盐矿物再沉淀而重返大气,全球岩溶碳汇净通量可能比0.1士0.02 GtC/a还要小1个数量级,即使在现今大气碳循环被严重扰动的条件下,似也不会成为一种重要的遗漏碳汇.%A few calculated results and two important karst carbon sink data quoted in the article are being questioned. It is argued for: (1)A few basic parameters being used in the article are inaccurate. The calculated results are perhaps over-estimated in 3~4 times, and possibly 200 times larger for north China karst region and the buried karst region, respectively. (2)Because of intrinsic shortage of standard tablet method as a karst carbon sink determining tool, the "global karst carbon sink" (6. 08×108 tC/a)obtained earlier is possibly overestimated by a factor of 4 or so. (3) Estimated values for newly proposed items of the global water circulation model for carbon sink are thought to be significantly overestimated. The net global water circulation carbon sink is probably only a little larger than that owing to carbonate weathering of rocks. (4)Simplified formula for carbon sink calculation used in the article has accounted for only the DIC originated from atmosphere/soil CO2 corrosion but not for all of their origins. Therefore it should be corrected for non-atmosphere/soil CO2 corrosion further. At a global scale the correction factor is believed to be about 0. 65. Consequently all results at this scale obtained earlier should be reduced by about 35 %. (5) Actual global karst carbon sink flux eventually is probably of the order of 0. 1+0. 02 GtC/a, which is about 6 times smaller than what is believed by authors of this article. Taking long term carbon cycle into account, given atmospheric carbon cycle nowadays is even in a strongly disturbed state, the net global karst carbon sink is probably much less than the order of 0. 01 GtC/a . It should not be considered as an important atmospheric carbon sink, especially comparing to the figure of photosynthesis (60 GtC/a).
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