Measuring Oceanic Carbon Dioxide

海洋二氧化碳系统对地球碳循环具有重要意义。据估计，海洋吸收了约30%的无源二氧化碳。然而，由于海洋中的二氧化碳含量是大气的50倍以上，因此海洋二氧化碳系统的变化很小，难以方便地检测。利用溶解二氧化碳逸度[FCCO_2]、总二氧化碳、pH、碱度、稳定碳同位素比值等在时间和空间上的变化来研究海洋二氧化碳系统，这些数据对于探测地球环境的变化具有很高的精确度和准确度。分析化学的最新发展使减少随机误差成为可能。然而，研究所或科学家之间的系统误差往往很严重，但并不广为人知。在这项研究中，我们讨论了在任何条件下最精确和最准确的海洋二氧化碳测量方法和标准…为了减少与世界上更多的材料的系统误差，并与加拿大海洋科学研究所(IOS)进行了分析工作的比对。海水的f(CO_2)值通常是通过使用喷淋式平衡器测定与样品海水平衡的空气并用ND=测定得到的。众所周知，为了获得高精度的f(CO_2)值，必须控制这种类型平衡器内的压力，因为f(CO_2)值受平衡器内压力的影响。标准物质是高精度测量总二氧化碳、pH、碱度和稳定碳同位素的比率。迪克森制定的pH和总二氧化碳标准是有用的，但碱度测量标准仍在讨论中。稳定碳同位素测量采用总碳分析标准进行比对。与IOS的比对结果如下：(1)北海道大学平衡仪测得的f(CO_2)值与iOS平衡仪测得的f(CO_2)值相同；(2)北海道大学测得的总二氧化碳含量与iOS测得的值相差约10mumole/L；(3)北海道大学测得的pH值与iOS测得的pH值之间存在系统误差；(4)瓶装海水样品和北海道大学制备的碳酸盐的稳定碳同位素比值约为0.7%。与内部监督办公室分析的结果不同。较少

Te ocean carbon dioxide system is important on the carbon cycle in the earth. It is estimated ocean uptakes about 30% of the anthoropogenic carbon dioxede. However, change of oceanic carbon dioxide system owing to the anthoropogenic carbon dioxede is too small to detect conveniently because the ocean contains more than 50 times as much carbon as the atmosphere. The ocean carbon dioxide system is investigated by the temporal and spatial variations of fugacity of dissolved carbon dioxede [fCCO_2)], total carbon dioxide, pH,alkalinity, ratio of stable carbon isotopes, etc. These data should be highly precise and accurate to detect the change in the earth's environment. Recent developments in analytical chemistry make it possible to reduce the random errors. However, the systematic errors between institutes or scientists are often serious, but not well known. In this study, we discussed most precise and accurate method of oceanic carbon dioxide measurements under any conditions and standar … More d materials to decrease of the systematic errors with the researchers in the world and conducted an intercomparison of analytical works with Institute of Ocean Sciences (IOS) in Canada.The f(CO_2) value of seawater is commonly obtained by the determination of the air equilibrated with sample seawater using the showering type equilibrator and detected with ND= It was known the pressure inside this type equilibrator has to be controlled in order to obtain high accurate f(CO_2) value because the f(CO_2) value is affected by the pressure inside the equilibrate.Standard materials are necessarily for the highly precise measurements of total carbon dioxide, pH,alkalinity and ratio of stable carbon isotopes. The standards for pH and total carbon dioxide developed by Dickson were useful, but standard for alkalinity measurement has been still under the discussion. Intercomparison of stable carbon isotope measurement using the standard for total carbon analysis was conducted by C.S.Wong. However, it was not enough to detect the small change induced anthoropogenic carbon dioxide.Results of the intercomparison with IOS are as follows : (1) the f(CO_2) value obtained by the equilibrator of Hokkaido University was same as that by IOS's equilibrator, (2) difference between amounts of total carbon dioxide measured by Hokkaido University and by IOS was about 10mumole/l, (3) there were systematic errors between pH values obtained by Hokkaido University and these by IOS doe to instrument's standardization and (4) ratios of stable carbon isotopes of bottled Seawater samples and carbonates prepared by Hokkaido University were about 0.7%。 deferent from these analyzed at IOS. Less