Nitrogen-15 in the Natural Environment

Techniques isotopiques (15N 18O) appliquees a l etude des nappes des alterites et du socle fracture de l ouest africain

“…Par exemple, la teneur en 15 N change lorsque l'azote organique dissous se minéralisé (NO3") ou lorsque l'azote minéral retourne à l'atmosphère sous l'effet de la dénitrification [Letolle, 1980]. [Fontes, 1980;Mook, 1980].…”

“…Il est possible de déterminer la source des nitrates dans les eaux contaminées par l'étude de la composition isotopique de l'azote [Heaton, 1986;Hùbner, 1986;Letolle, 1980]. La méthode est simple, elle repose sur le postulat suivant: la composition isotopique de l'azote du contaminant reflète celle de la source.…”

Compilation of minimum and maximum isotope ratios of selected elements in naturally occurring terrestrial materials and reagents

“…Ranges in the stable isotopic composition of naturally occurring nitrogen-bearing materials are shown in table 14 and figure 5. Compilations of nitrogen isotope-abundance variations and isotope-fractionation mechanisms include Letolle (1980), Heaton (1986), Hiibner (1986, Owens (1987), and Kendall (1998).…”

Taux d'enfouissement et altérations diagénétiques de matière organique azotée dans le nord-ouest atlantique subarctique =

“…Compilation of various reported data by Létolle (1980) has indicated that the nitrogen stable isotopic compositions of marine planktonic OM range from 4%o to 10%o with an average of 6%o. Because of the differences in the isotopic compositions between land and marine plants, nitrogen stable isotopic compositions of OM have also been used separately or in combination to imply the influence of terrestrial OM in the marine environment (Peters et al, 1978;Macko, 1983;Muzuka etal., 1991).…”

“…1.10). With respect to aquatic environments, Létolle, 1980). phytoplankton mainly utilize dissolved inorganic nitrogen in the form of nitrate during the synthesis of OM, although other forms of nitrogen, such as dissolved molecular nitrogen, ammonium, and nitrite, are also used (Saino and Hattori, 1985).…”