dc.contributor.author |
Waterhouse, JS
|
en_US |
dc.contributor.author |
Switsur, VR
|
en_US |
dc.contributor.author |
Barker, AC
|
en_US |
dc.contributor.author |
Carter, AHC
|
en_US |
dc.contributor.author |
Robertson, I
|
en_US |
dc.date.accessioned |
2007-02-08T07:32:12Z |
en_US |
dc.date.accessioned |
2007-06-07T10:04:59Z |
|
dc.date.available |
2007-02-08T07:32:12Z |
en_US |
dc.date.available |
2007-06-07T10:04:59Z |
|
dc.date.copyright |
|
en_US |
dc.date.issued |
2002-07-30 |
en_US |
dc.identifier.citation |
Waterhouse, JS, et al. 2002. Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?. Earth and Planetary Science Letters, vol 201(2), pp 421-430 |
en_US |
dc.identifier.issn |
0012-821X |
en_US |
dc.identifier.uri |
http://hdl.handle.net/10204/1641
|
en_US |
dc.identifier.uri |
http://hdl.handle.net/10204/1641
|
|
dc.description.abstract |
Annual oxygen and hydrogen isotope ratios in the alpha-cellulose of the latewood of oak (Quercus robur L.) growing on well-drained ground in Norfolk, UK have been measured. The authors have compared the observed values of isotope ratios with those calculated using equations that allow for isotopic fractionation during the transfer of oxygen and hydrogen from source water taken by the tree to cellulose laid down in the cambium. The equations constitute a model in which isotopic fractionation occurs during evaporative enrichment within the leaf and during isotopic change between carbohydrates and water in the trunk during cellulose synthesis. From the relationship between isotope ratios in precipitation and alpha-cellulose, it is presumed that the source water used by the tree comprises a constant mixture of groundwater and precipitation, chiefly from the months of May, June and July of the growth year. By selection of isotopic fractionation factors and the degree of isotope exchange within the trunk, it is proficient to model the observed annual values of oxygen isotope ratios of alpha-cellulose to a significant level (r = 0.77, P < 0.01). When the same model is applied to hydrogen isotope ratios, results are found, and predictions can be made about the average value over the time series, however the year-to-year variation can no longer be calculated. It is suggested that this loss of environmental signal in the hydrogen isotopes is caused by differences in the kinetic isotope effects of the biochemical reactions involved in the fixation of hydrogen in different positions of the glucose molecule. Owing to these effects, the hydrogen isotope ratios of cellulose can vary in a way not anticipated in current models and hence may induce non-climatic 'noise' in the hydrogen isotope time series. |
en_US |
dc.format.extent |
304349 bytes |
en_US |
dc.format.mimetype |
application/pdf |
en_US |
dc.language.iso |
en |
en_US |
dc.publisher |
Elsevier Science BV |
en_US |
dc.rights |
Copyright: 2002 Elsevier Science BV |
en_US |
dc.source |
|
en_US |
dc.subject |
Isotopic fractionation |
en_US |
dc.subject |
Oxygen isotopes |
en_US |
dc.subject |
Hydrogen isotopes |
en_US |
dc.subject |
Groundwater |
en_US |
dc.subject |
Alpha-cellulose |
en_US |
dc.subject |
Geochemistry |
en_US |
dc.subject |
Precipitation |
en_US |
dc.subject |
Sciences |
en_US |
dc.title |
Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values? |
en_US |
dc.type |
Article |
en_US |
dc.identifier.apacitation |
Waterhouse, J., Switsur, V., Barker, A., Carter, A., & Robertson, I. (2002). Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?. http://hdl.handle.net/10204/1641 |
en_ZA |
dc.identifier.chicagocitation |
Waterhouse, JS, VR Switsur, AC Barker, AHC Carter, and I Robertson "Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?." (2002) http://hdl.handle.net/10204/1641 |
en_ZA |
dc.identifier.vancouvercitation |
Waterhouse J, Switsur V, Barker A, Carter A, Robertson I. Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?. 2002; http://hdl.handle.net/10204/1641. |
en_ZA |
dc.identifier.ris |
TY - Article
AU - Waterhouse, JS
AU - Switsur, VR
AU - Barker, AC
AU - Carter, AHC
AU - Robertson, I
AB - Annual oxygen and hydrogen isotope ratios in the alpha-cellulose of the latewood of oak (Quercus robur L.) growing on well-drained ground in Norfolk, UK have been measured. The authors have compared the observed values of isotope ratios with those calculated using equations that allow for isotopic fractionation during the transfer of oxygen and hydrogen from source water taken by the tree to cellulose laid down in the cambium. The equations constitute a model in which isotopic fractionation occurs during evaporative enrichment within the leaf and during isotopic change between carbohydrates and water in the trunk during cellulose synthesis. From the relationship between isotope ratios in precipitation and alpha-cellulose, it is presumed that the source water used by the tree comprises a constant mixture of groundwater and precipitation, chiefly from the months of May, June and July of the growth year. By selection of isotopic fractionation factors and the degree of isotope exchange within the trunk, it is proficient to model the observed annual values of oxygen isotope ratios of alpha-cellulose to a significant level (r = 0.77, P < 0.01). When the same model is applied to hydrogen isotope ratios, results are found, and predictions can be made about the average value over the time series, however the year-to-year variation can no longer be calculated. It is suggested that this loss of environmental signal in the hydrogen isotopes is caused by differences in the kinetic isotope effects of the biochemical reactions involved in the fixation of hydrogen in different positions of the glucose molecule. Owing to these effects, the hydrogen isotope ratios of cellulose can vary in a way not anticipated in current models and hence may induce non-climatic 'noise' in the hydrogen isotope time series.
DA - 2002-07-30
DB - ResearchSpace
DP - CSIR
KW - Isotopic fractionation
KW - Oxygen isotopes
KW - Hydrogen isotopes
KW - Groundwater
KW - Alpha-cellulose
KW - Geochemistry
KW - Precipitation
KW - Sciences
LK - https://researchspace.csir.co.za
PY - 2002
SM - 0012-821X
T1 - Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?
TI - Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?
UR - http://hdl.handle.net/10204/1641
ER -
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en_ZA |