The Isotopic Composition of Sea Water
The Isotopic Composition of Sea Water
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海水的同位素组成
DOI：
10.1021/ja01317a037
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发表时间：
1934
影响因子：
15
通讯作者：
E. Gilfillan
中科院分区：
文献类型：
--
作者：
E. Gilfillan
在WD Urry博士的建议下，在Lat.北纬36 27”久了西经68 38”由伍兹霍尔海洋学研究所测定的4500米深处的海水深度。根据玻尔兹曼分布定理，可以证明，如果在海洋的较深部分达到统计平衡，那么来自4500米深处的纯水的重量最多应比水重百万分之七。由于重力场中各种同位素物质的分离，深海水与实验室蒸馏水的差别为百万分之2.3，但令人惊奇的是，表层海水也有同样的差别。这表明，海洋还没有达到统计平衡，而观测到的海水和陆地水之间的差异可能是由于蒸馏。根据Washburn、Smith和Frandsen的实验，可以计算出预期对蒸馏的影响的大小。他们发现，比重为1.001376的水（推测是由于重氢）比普通水的沸点高0.02。假定拉乌尔定律和已知的水的蒸气压随温度的变化，人们发现水蒸气比与之相等的液态水少含2.8%的20。使用Bleakney和Gould 3发现的H1和H2的比例值（1/5000），人们发现从大量水中蒸馏出的第一种液体由于H2单独的原因应该轻0.3ppm。如果现在假设在水的蒸气压中用O 18代替O 16的影响与用H 2代替H 1的影响相同，并使用Mecke和Childs 4（1/630）对O 18丰度的估计，则得到的影响为百万分之5.0。该计算表明，观察到的效应可能是由于O 18所致。
At the suggestion of Dr. WD Urry, the specific gravity of a sample of deep-sea water takenin Lat. 36 27" N. Long. 68 38" W. at a depth of 4500 meters by the Woods Hole Oceanographic Institution has been determined. On the basis of the Boltzmann distribution theorem it can be shown that if in the deeper parts of the ocean statistical equilibrium has been reached, pure water from a depth of 4500 meters should be heavier by a maximum of 7 parts per million than wa. ter from the surface, due to separation of the various isotopic species in the gravitational field. A difference of 2.3 parts per million be-tween deep-sea water and the laboratory dis-tilled water was found, but we were greatly as-tonished to discover that surface sea water shows the same difference. This indicates that the sea has not reached statistical equilibrium, and that theobserved difference between sea and land water is perhaps due to distillation. From the experiments of Washburn, Smith and Frandsen2 the magnitude of the effect to be expected on distillation can be calculated. They found that water of specific gravity 1.001376 (supposedly due to heavy hydrogen) boiled 0.02 higherthan ordinary water. Assuming Raoult’s law and the known variation of the vapor pressure of water with temperature, one finds that water vapor contains 2.8% less 20 than the liquid water with which it is in equi-librium. Using the value for the ratio of the amounts of H1 and H2 found by Bleakney and Gould3 (1 in 5000) one finds that the firstliquid distilling from a large amount of water should be lighter by 0.3 part per million due to H2 alone. If one now assumes that the effect of the sub-stitution of O18 for O16 in the vapor pressure of water is the same as the substitution of H2 for H1 and uses the estimate of Mecke and Childs4 (1 in 630) for the abundance of O18 one obtains an effect of 5.0 parts per million. This calculation indicates that the observed effect may be as-sumed due to O18.