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TitleTree-ring stable isotopes and historical perspectives on pollution - an overview
AuthorSavard, M M
SourceEnvironmental Pollution vol. 158, 2010 p. 2007-2013,
Alt SeriesEarth Sciences Sector, Contribution Series 20080631
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
Subjectsenvironmental geology; Science and Technology; environmental analysis; environmental studies; environmental impacts; pollution; pollutants; vegetation; stable isotope studies; isotopes; hydrogen isotopes; carbon isotopes; oxygen isotopes; dendrochronology; nitrogen isotopes; tree rings; cumulative effects
Illustrationsgraphs; tables
ProgramEnvironment and Health
ProgramMetals in the Environment (MITE)
AbstractHydrogen (d2H), carbon (d13C), oxygen (d18O) and nitrogen (d15N) isotopes of tree rings growing in field conditions can be indicative of past pollution effects. The characteristic d13C trend is a positive shift generally explained by invoking closure of stomata, but experimental studies suggest that increased rates of carboxylation could also generate such trends. In many cases the d18O and d2H values decrease in trees exposed to pollution and exhibit inverse coinciding long-term trends with d13C values. However, some trees exposed to diffuse pollution and experimental conditions can show an increase or no d18O change even if d13C values increase. These diverse responses depend on how stress conditions modify physiological functions such as stomatal conductance, carboxylation, respiration, and perhaps water assimilation by the root system. Recent studies suggest that d15N changes in trees can be caused by soil acidification and accumulation of anthropogenic emissions with isotopic signals deviating from natural N.