31 巻 (2016) 1 号 p. 5-14
Abstract In this paper, recent advances in using stable isotopes of atmospheric nitrate to trace the origin and fate are reviewed. While nitrogen isotopes have been used as the indicators of NOx source contributions to the atmospheric nitrate, cautions must be taken for the isotopic fractionations during the photochemical reactions of NOX in atmosphere. On the other hand, the triple oxygen isotope composition (Δ17O) is a robust tracer for the photochemical reaction path of NOX in atmosphere. Besides, the triple oxygen isotope composition can be applied to trace the fate of atmospheric nitrate and to evaluate biological processing of nitrate within the earth surface ecosystems.