Effects of salt water immersion caused by a tsunami on δ13C and δ18O values of Pinus thunbergii tree‐ring cellulose

Abstract

AbstractPinus thunbergii trees growing on Pacific coastal sand dunes in Japan were immersed by the tsunami that followed the Great East Japan Earthquake on 11 March 2011. Even trees that survived direct physical damage began to die during the following summer, probably because of the physiological stress of salt water immersion. The objectives of this study were to analyze the relationship between the carbon and oxygen isotope values (δ13C and δ18O, respectively) of P. thunbergii tree‐ring cellulose and the effects of salt water immersion caused by the tsunami. Pinus thunbergii trees were sampled in Yamamoto, Miyagi Prefecture, and in Misawa, Aomori Prefecture. Each tree‐ring that formed between 2008 and 2012 was sliced into four to eight equal subdivisions, and the isotope values were analyzed at a high time‐scale resolution. Tree rings that were immersed in seawater from the tsunami had higher δ13C values in the earlywood that formed in the spring following the tsunami than those formed prior to the disaster. This increase in δ13C values was likely caused by osmotic stress from root immersion in salt water. We did not observe a clear change in tree‐ring δ18O values after the tsunami. This lack of variance might have resulted from the post‐photosynthetic exchange of carbonyl oxygens with non‐18O‐enriched xylem water.