Nitrogen isotope systematics

Kao, S. J., and Liu, K. K. (2000). Stable carbon and nitrogen isotope systematics in a human-disturbed watershed (Lanyang-Hsi) in Taiwan and the estimation of biogenic particulate organic carbon and nitrogen fluxes. Global Biogeochem. Cycles. 14(1), 189—198. 

Bulanova G. P., Pearson D. G., Hauri E. H., and Griffin William L. (2002) Carbon and nitrogen isotope systematics within a sector-growth diamond from the Mir kimberlite, Yakutia. Chem. Geol. 188, 105-123. 

Our results do not support the protein stress model. However, this model may apply in cases where stress is intermittent and results in tissue loss, as observed in the study of crows (Hobson and Clark 1992). Low protein levels throughout life after weaning may have produced overall slow and reduced rate of growth rather than tissue loss. Adult rats fed protein-deficient diets after maturation show systematic losses of nitrogen from most tissues that are in proportion to their turnover rates and masses (Uezu et al. 1983). Perhaps tissue nitrogen isotope enrichment may occur under these conditions. New experiments are needed to evaluate this hypothesis. 

Pearson D. G., Shirey S. B., Bulanova G. P., Carlson R. W., and Milledge H. J. (1999a) Re-Os isotope measurements of single sulfide inclusions in a Siberian diamond and its nitrogen aggregation systematics. Geochim. Cosmochim. Acta 63(5), 703 -711. 

Dr. Erickson For those interested in coordination chemistry, certain other transition metal atoms are suitable for Mossbauer spectroscopy. One in particular is ruthenium which is just below iron in the Periodic Table. It is a difficult isotope to work with since it requires helium temperatures almost exclusively. I don t know whether it is possible to work at nitrogen temperatures or not, but Kistner at Brookhaven has examined various ruthenium compounds from the 2-j- to the 8+ oxidation states with interesting results. These are not published yet, but at least his work offers the possibility of going down one element below the other in the Periodic Table to study chemical effects. Osmium, which is below ruthenium, can also be Mossbauered. Some sort of systematic study like this involving elements in the various transition series would be extremely interesting. 

Wolfe has presented an excellent description of the systematic application of stable and radioactive isotope tracers in determining the kinetics of urea production, urea recycling, and interorgan nitrogen transfer in living systems. 

Gas Chromatography Sano et al. first published a systematic approach to measuring the carbon isotope ratios of GC peaks in 1976 [34]. Further developments occurred over the years however, it was not until 1988 that gas chromatography-isotope ratio mass spectrometry (GC-IRMS) systems were commercially available. Since this time, the systems have been enhanced and extended to include the analysis of nitrogen, oxygen, and hydrogen isotope values [10 2]. Jasper et al. [35] describe the specificity of the GC-IRMS technique... 

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