Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and ocean in Taiwan and its vicinity
Molecules containing two rare isotopes (e.g., <sup>13</sup>C<sup>18</sup>O<sup>16</sup>O in CO<sub>2</sub>), called clumped isotopes, in atmospheric CO<sub>2</sub> are powerful tools to provide an alternative way to independently constrain...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/5297/2016/bg-13-5297-2016.pdf |
| _version_ | 1818955231859310592 |
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| author | A. H. Laskar M.-C. Liang |
| author_facet | A. H. Laskar M.-C. Liang |
| author_sort | A. H. Laskar |
| collection | DOAJ |
| description | Molecules containing two rare isotopes (e.g., <sup>13</sup>C<sup>18</sup>O<sup>16</sup>O in
CO<sub>2</sub>), called clumped isotopes, in atmospheric CO<sub>2</sub> are powerful
tools to provide an alternative way to independently constrain the sources of
CO<sub>2</sub> in the atmosphere because of their unique physical and chemical
properties. We presented clumped isotope data (Δ<sub>47</sub>) in near-surface
atmospheric CO<sub>2</sub> from urban, suburban, ocean, coast, high mountain
( ∼ 3.2 km a.s.l.) and forest in Taiwan and its vicinity. The primary
goal of the study was to use the unique Δ<sub>47</sub> signature in
atmospheric CO<sub>2</sub> to show the extents of its
deviations from thermodynamic equilibrium due to different processes such as
photosynthesis, respiration and local anthropogenic emissions, which the
commonly used tracers such as δ<sup>13</sup>C and δ<sup>18</sup>O cannot provide. We also explored the potential of Δ<sub>47</sub> to identify/quantify the contribution of CO<sub>2</sub> from various sources. Atmospheric CO<sub>2</sub> over ocean was found to be in thermodynamic equilibrium with the surrounding surface sea water. Respired CO<sub>2</sub> was also in close thermodynamic
equilibrium at ambient air temperature. In contrast, photosynthetic activity
result in significant deviation in Δ<sub>47</sub> values from that expected
thermodynamically. The disequilibrium could be a consequence of kinetic
effects associated with the diffusion of CO<sub>2</sub> in and out of the leaf
stomata. We observed that δ<sup>18</sup>O and Δ<sub>47</sub> do not vary
similarly when photosynthesis was involved unlike simple water–CO<sub>2</sub>
exchange. Additionally we obtained Δ<sub>47</sub> values of car exhaust
CO<sub>2</sub> that were significantly lower than the atmospheric CO<sub>2</sub> but
higher than that expected at the combustion temperature. In urban and
suburban regions, the Δ<sub>47</sub> values were found to be lower than the
thermodynamic equilibrium values at the ambient temperature, suggesting
contributions from local combustion emission. |
| first_indexed | 2024-12-20T10:34:47Z |
| format | Article |
| id | doaj.art-e631b34f20bc419980d4c7bcaf05dbcc |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-20T10:34:47Z |
| publishDate | 2016-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-e631b34f20bc419980d4c7bcaf05dbcc2022-12-21T19:43:38ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-09-0113185297531410.5194/bg-13-5297-2016Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and ocean in Taiwan and its vicinityA. H. Laskar0M.-C. Liang1Research Center for Environmental Changes, Academia Sinica, Taipei, TaiwanResearch Center for Environmental Changes, Academia Sinica, Taipei, TaiwanMolecules containing two rare isotopes (e.g., <sup>13</sup>C<sup>18</sup>O<sup>16</sup>O in CO<sub>2</sub>), called clumped isotopes, in atmospheric CO<sub>2</sub> are powerful tools to provide an alternative way to independently constrain the sources of CO<sub>2</sub> in the atmosphere because of their unique physical and chemical properties. We presented clumped isotope data (Δ<sub>47</sub>) in near-surface atmospheric CO<sub>2</sub> from urban, suburban, ocean, coast, high mountain ( ∼ 3.2 km a.s.l.) and forest in Taiwan and its vicinity. The primary goal of the study was to use the unique Δ<sub>47</sub> signature in atmospheric CO<sub>2</sub> to show the extents of its deviations from thermodynamic equilibrium due to different processes such as photosynthesis, respiration and local anthropogenic emissions, which the commonly used tracers such as δ<sup>13</sup>C and δ<sup>18</sup>O cannot provide. We also explored the potential of Δ<sub>47</sub> to identify/quantify the contribution of CO<sub>2</sub> from various sources. Atmospheric CO<sub>2</sub> over ocean was found to be in thermodynamic equilibrium with the surrounding surface sea water. Respired CO<sub>2</sub> was also in close thermodynamic equilibrium at ambient air temperature. In contrast, photosynthetic activity result in significant deviation in Δ<sub>47</sub> values from that expected thermodynamically. The disequilibrium could be a consequence of kinetic effects associated with the diffusion of CO<sub>2</sub> in and out of the leaf stomata. We observed that δ<sup>18</sup>O and Δ<sub>47</sub> do not vary similarly when photosynthesis was involved unlike simple water–CO<sub>2</sub> exchange. Additionally we obtained Δ<sub>47</sub> values of car exhaust CO<sub>2</sub> that were significantly lower than the atmospheric CO<sub>2</sub> but higher than that expected at the combustion temperature. In urban and suburban regions, the Δ<sub>47</sub> values were found to be lower than the thermodynamic equilibrium values at the ambient temperature, suggesting contributions from local combustion emission.http://www.biogeosciences.net/13/5297/2016/bg-13-5297-2016.pdf |
| spellingShingle | A. H. Laskar M.-C. Liang Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and ocean in Taiwan and its vicinity Biogeosciences |
| title | Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and
ocean in Taiwan and its vicinity |
| title_full | Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and
ocean in Taiwan and its vicinity |
| title_fullStr | Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and
ocean in Taiwan and its vicinity |
| title_full_unstemmed | Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and
ocean in Taiwan and its vicinity |
| title_short | Clumped isotopes in near-surface atmospheric CO<sub>2</sub> over land, coast and
ocean in Taiwan and its vicinity |
| title_sort | clumped isotopes in near surface atmospheric co sub 2 sub over land coast and ocean in taiwan and its vicinity |
| url | http://www.biogeosciences.net/13/5297/2016/bg-13-5297-2016.pdf |
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