Influence of air pollution and site conditions on trends of carbon and oxygen isotope ratios in tree ring cellulose

Abstract

Oxygen and carbon isotopic compositions of tree ring cellulose (delta13Ccell and delta18Ocell) were measured for pines growing at four sites in east Germany. Three sites differed markedly in soil water availability within a short distance and the fourth site served as a reference. The choice of the sites was guided by the desire to detect effects of air pollution on the long-term trend of isotopic compositions and to examine the influence of soil water availability on the relationship between the carbon and oxygen isotope ratios. Locations in east Germany are particularly well suited for the study of pollution effects because there was a steady increase in environmental contamination until the German Reunification in 1990, followed by a sharp decline due to the implementation of stricter environmental standards. The long-term trend of delta13Ccell showed an extraordinary increase in the period 1945-1990 and a rapid decrease after 1990, whereas delta18Ocell remained nearly constant. The increase of delta13Ccell is explained by secondary fractionation caused by phytotoxicity of SO2. Two effects are mainly responsible for the secondary fractionation under SO2 exposure: increase of dark respiration, and changes in photosynthate allocation and partitioning. Both effects do not influence delta18Ocell. Furthermore, a significant positive correlation between the year-to-year variations of carbon and oxygen isotope ratios (delta13Cresid and delta18Oresid) has been found for all sites. The slopes of the relationship between delta13Cresid and delta18Oresid differ insignificantly. It is concluded that this relationship is not influenced by soil water availability but by climatic variables.

Climatic sensitivity of δ13C in tree rings of Quercus robur L., Populus tremula L. and Pinus sylvestris L. in Vilnius region (eastern Lithuania)

“…2). Such trends in trees from polluted sites were observed by the other authors (Rinne et al, 2010;Savard, 2010;Wagner & Wagner, 2006). Typical short-term variations of δ 13 C in trees from unpolluted sites are ~0.5‰, whereas at polluted sites, where the SO 2 concentration reaches the critical concentration limit of 20-25 μg/m 3 or near highways with increased NO x and NH 3 concentrations (Guerrieri et al, 2009), positive shifts in δ 13 C values can exceed +3‰ in comparison to mean stable isotope values of rings grown during the clean periods (Savard, 2010).…”

“…O than on delta δ 13 C values (Guerrieri et al, 2009;Rinne et al, 2010;Savard, 2010;Wagner & Wagner, 2006). This can be explained by the isotopic equilibration between the leaf sucrose and xylem water during cellulose and/or lignin synthesis (McCarroll & Loader, 2004;Rinne et al, 2010).…”

“…As the influence of anthropogenic pollution on the tree ring isotope ratio was observed in earlier works (Rinne et al, 2010;Savard, 2010;Wagner & Wagner, 2006), the rural-urban fringe sites for tree samples were selected to check the possibility of using trees growing under these conditions to observe significant correlations with climate parameters.…”

Growth and physiological responses to ozone and mild drought stress of tree species with different ecological requirements

“…Amongst these, the analysis of stable carbon isotope signatures (d 13 C) has proven to be useful in assessing plant responses to several environmental stress factors, including drought and air pollution (Martin and Sutherland 1990;Saurer et al 1995;Dawson et al 2002;Wagner and Wagner 2006). During photosynthesis, plants discriminate between 13 CO 2 and 12 CO 2 .…”

Reconstructing Atmospheric CO2Concentration Using Its Relationship with Carbon Isotope Variations in Annual Tree Ring of Red Pine

“…Increase of atmospheric CO2 concentration ([CO2]) due to fossil fuel combustion from the industrial period (since 1850) is believed to be a primary reason of global warming (IPCC, 2007 (Wagner and Wagner, 2006;Kwak et al, 2009a). Such information is important to prepare area-specific agricultural countermeasures against elevating [CO2].…”