Schulze E, Lohmeyer S, Giese W
a Fachgebiet Medizinische Physik der Tierärztlichen Hochschule , Hannover , Deutschland.
Isotopes Environ Health Stud. 1997 Jul;33(1-2):75-9. doi: 10.1080/10256019708036334.
Abstract Naturally produced methane shows different δ(13)C-values with respect to its origin, e.g., geological or biological. Methane-production of ruminants is considered to be the dominant source from the animal kingdom. Isotopic values of rumen methane-given in literature-range between -80‰ and -50‰ and are related to feed composition and also sampling techniques. Keeping cows, camels and sheep under identical feed conditions and sampling rumen gases via implanted fistulae we compared δ(PDB) (13)C-values of methane and CO(2) between the species. Referring to mean values obtained from 4 or 5 samples at different times of 11 animals (n = 47) we calculated δ(PDB) (13)C-medians resulting in small but not significant differences within and significant differences between the species for CO(2) and methane. The δ(PDB) (13)C-differences between methane and CO(2) were statistically equal within and also between the species. Therefore a linear regression of methane values on CO(2) is appropriate and leads to: δ(PDB) (13)C(methane)‰ = 1,57 * δ(PDB) (13)C(CO(2))‰-47‰ with a correlation coefficient of r = 0,87.
摘要 天然产生的甲烷因其来源不同，例如地质来源或生物来源，而具有不同的δ(13)C值。反刍动物产生的甲烷被认为是动物界的主要来源。文献中给出的瘤胃甲烷的同位素值在-80‰至-50‰之间，并且与饲料组成以及采样技术有关。在相同的饲料条件下饲养奶牛、骆驼和绵羊，并通过植入的瘘管采集瘤胃气体，我们比较了不同物种之间甲烷和CO(2)的δ(PDB)(13)C值。参照从11只动物（n = 47）在不同时间采集的4或5个样本获得的平均值，我们计算了δ(PDB)(13)C中位数，结果显示不同物种内部CO(2)和甲烷的差异较小但不显著，而不同物种之间的差异显著。甲烷和CO(2)之间的δ(PDB)(13)C差异在物种内部以及物种之间在统计学上是相等的。因此，用CO(2)的值对甲烷值进行线性回归是合适的，结果为：δ(PDB)(13)C(甲烷)‰ = 1.57 * δ(PDB)(13)C(CO(2))‰ - 47‰，相关系数r = 0.87。
