Temporal changes in tree-ring nitrogen of Pinus thunbergii trees exposed to Black-tailed Gull (Larus crassirostris) breeding colonies

Lopez C M Larry, Mizota Chitoshi, Yamanaka Toshiro, Nobori Yoshihiro

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Natural abundances of 15N/14N ratios (commonly designated by δ15N notation) of annual rings from Pinus thunbergii trees were determined after transplantation from a nursery to breeding colonies of Black-tailed Gull (Larus crassirostris) in Miyagi and Aomori and a control site in Yamagata, in northeastern Japan. Tree-rings were collected in July/August/September, 2009. Transplanting was conducted in the year 2000 in the Miyagi site, whereas there is no information about transplanting data in the Aomori and Yamagata sites. Soils associated with piscivorous (fish eating) avian colonies receive large seasonal input of organic N in the form of feces. The organic N is microbiologically transformed into inorganic N in soils, from which P. thunbergii derives its N. The resulting NH4- and NO3-N are characterized by distinctly heavy δ15N ratios, due to coupled processes of mineralization, volatilization, nitrification and denitrification of feces. In general, total N concentration along with δ15N values stored in the annual rings of P. thunbergii increased steadily after transplanting from the nursery to locations under continued avian N input. Tree-ring N content and isotopic ratios provided a reliable record of past annual available soil N caused by changes in the Black-tailed Gull population, and thus can serve as an environmental tool to estimate past avian population dynamics.

Original languageEnglish
Pages (from-to)1699-1702
Number of pages4
JournalApplied Geochemistry
Issue number11
Publication statusPublished - Nov 2010


ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Geochemistry and Petrology

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