title: Isotopic evidence in tree rings for historical changes in atmospheric sulfur sources.
abstract: Little is understood about the usefulness of sulfur isotopic ratios (sigma 34S) in tree rings because the sulfur content in rings is generally insufficient for analysis using conventional methods. We present sigma 34S values of the water-soluble and the organically bound sulfur fractions in rings of coniferous trees grown in Japan, analyzed using a large-volume oxygen bomb. Comparing the sigma 34S values of the organically bound fraction in tree rings with past atmospheric sulfur concentrations and with those of their sources, we find clear evidence that the sigma 34S values of the organically bound fraction in the rings are dependent upon the values of the atmospheric sulfur sources. The evidence suggests that the sigma 34S values in tree rings are a useful chronological proxy for evaluating possible causes of past atmospheric sulfur pollution.
authors.affiliation: Department of Chemistry and Physics of Condensed Matter, Graduate School of Science, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-0053, Japan. kawamura@keea.or.jp
authors.forename: Hidehisa
authors.initials: H
authors.lastname: Kawamura
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Matsuoka
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Momoshima
authors.forename: Masami
authors.initials: M
authors.lastname: Koike
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takashima
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods; D007564:Japan; D013455:Sulfur / Q000032:analysis* / Q000378:metabolism; D013460:Sulfur Isotopes; D064028:Tracheophyta / Q000254:growth & development / Q000378:metabolism*; D014197:Trees / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000393:Air Pollutants; D013460:Sulfur Isotopes; D013455:Sulfur