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Soil and Environmental Analysis: Modern Instrumental Techniques - Chapter 9

Các yếu tố ánh sáng sinh học quan trọng là hydro, carbon, nitơ, oxy và lưu huỳnh. Mỗi người có ít nhất hai đồng vị ổn định, và đồng vị có nhiều nhất trong một cặp là nhẹ hơn: 2H/1H (tức là, D / H), 13C/12C, 15 N/14N, 18O/16O, và 34S/32S. Các biến thể trong sự phong phú đồng vị có thể tiết lộ và định lượng các quá trình trong đó những yếu tố này có liên quan đến. Các quá trình này bao gồm quang hợp, hô hấp, bốc hơi, doanh thu các chất hữu cơ, và C,. | 9 Stable Isotope Analysis and Applications Charles M. Scrimgeour The Scottish Crop Research Institute Dundee Scotland David Robinson The University of Aberdeen Aberdeen Scotland 1. INTRODUCTION The biologically important light elements are hydrogen carbon nitrogen oxygen and sulfur. Each has at least two stable isotopes and the most abundant isotope in a pair is the lighter 2H 1H i.e. D H C C 15xT 14NT 18 16 A o Tl I 3 0 320 A 9 rì 9 fì Í9T9 c ỉn 9 I M T9 fl 9 T9 r PC PCITt rPUPCll N N O O and S S. Variations in isotope abundances can reveal and quantify processes in which these elements are involved. Such processes include photosynthesis respiration evaporation organic matter turnover and C N and S metabolism. Stable isotopes can also be used in activities as diverse as monitoring pollution events tracking animals food sources reconstructing past climates identifying plants water sources and untangling biochemical pathways. Valuable general references include Fritz and Fontes 1980 Vose 1980 O Leary 1981 1988 1993 Hoefs 1987 Raven 1987 Rundel et al. 1989 Coleman and Fry 1991 Griffiths 1991 1998 Krouse and Grinenko 1991 Robinson and Smith 1991 Handley and Raven 1992 O Leary et al. 1992 Ehleringer et al. 1993 Engel and Macko 1993 Knowles and Blackburn 1993 Lajtha and Michener 1994 Boutton and Yamasaki 1996 Handley and Scrimgeour 1997 Kendall and McDonnell 1998 Bingham et al. 2000 Mook 2001 Robinson 2001 and Dawson et al. 2002 . The Internet is being used increasingly as a source K K Copyright n 2004 by Marcel Dekker Inc. All Rights Reserved. of the latest stable isotope information. The ISOGEOCHEM website at http geology.uvm.edu isogeochem.html is a good place to start Kendall and Campbell 1998 list others. Many of the approaches described in these references rely on isotopes being used as tracers. An isotopically distinct but chemically indistinguishable material the tracer is introduced into an experimental system and isotope abundances are later measured in .