| Titre | Impact of increasing CO2, and air pollutants (NOx, SO2, O3) on the stable isotope ratios in tree rings |
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| Auteur | Siegwolf, R T W; Savard, M M ; Grams, T E E; Voelker, S L |
| Source | Stable isotopes in tree rings; 2022 p. 675-710  Accès
ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200471 |
| Éditeur | Springer |
| Document | livre |
| Lang. | anglais |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Sujets | gaz carbonique; pollution; substances polluantes; isotopes; études des isotopes stables; Arbre; géologie de l'environnement; Nature et environnement |
| Illustrations | diagrammes schématiques |
| Programme | Géosciences environnementales Études et évaluations environnementales |
| Diffusé | 2022 06 07 |
| Résumé | (disponible en anglais seulement)
Anthropogenic activities such as industrialization, land use change and intensification of agriculture strongly contribute to changes in the concentrations of
atmospheric trace gases. Carbon dioxide (CO2), oxidized N compounds (NOx), sulfur dioxide (SO2) and ozone (O3) have particularly significant impacts on plant physiology. CO2, the substrate for plant photosynthesis, is in the focus of interest as the
ambiguous effect of its increasing concentration is controversially discussed. Is its increase beneficial for plants or are plants non-responsive? NOx, a product of combustion and lightning, can have either fertilizing or toxic effects depending on
the concentration and form. This is also the case for reduced forms of nitrogen (NHy), which are mostly emitted from agricultural and industrial activities. In combination CO2 and N compounds can have a fertilizing effect. SO2 and ground-level O3 are
mostly phytotoxic, depending on their concentrations, daily and seasonal exposure dynamics, and tree health condition. Elevated concentrations of both substances arise from industrial combustion processes and car emissions. All of the above-mentioned
gaseous compounds affect plant metabolism in their specific ways and to different degrees. This impacts the isotope fractionation leaving specific fingerprints in the C, O, (H) and N isotope ratios of organic matter. In this chapter we will show how
the impact of increasing CO2 and air pollutants are reflected in the isotopic ratios of tree rings. Increasing CO2 shows a considerable variation in responses of d13C and to a minor degree in d18O. Ozone and SO2 exposure cause an overall increase of
the d13C values in tree rings and a slight decrease in d18O, mimicking an increase in net photosynthesis (AN) and to a minor degree in stomatal conductance (gs). However, directly measured AN and gs values show the opposite, which does not always
correspond with the isotope derived gas exchange data. NO2 concentration as it is found near highly frequented freeways or industrial plants causes an increase of d13C while d18O decreases. This indicates an increase in both AN and gs, which
corresponds well with directly measured gas exchange data. Thus the air quality situation must be taken in consideration for the interpretation of isotope values in tree rings. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Les activités humaines telles que l'industrialisation, le changement d'affectation des terres et l'agriculture contribuent à augmenter les
quantités atmosphériques de dioxyde de carbone (CO2), des composés de N oxydés (NOx), de dioxyde de soufre (SO2) et d'ozone (O3). Tous ces composés influencent le métabolisme des plantes de manière spécifique et à différents degrés, laissant leurs
empreintes dans les rapports isotopiques C, O (H) et N de la matière organique. Dans ce chapitre, nous montrons comment les impacts de l'augmentation du CO2 et des polluants atmosphériques se reflètent dans les rapports isotopiques des cernes des
arbres, des indicateurs potentiels de changements environnementaux. |
| GEOSCAN ID | 327309 |
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