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δ(13)C-CH4 reveals CH4 variations over oceans from mid-latitudes to the Arctic.

Yu J, Xie Z, Sun L, Kang H, He P, Xing G - Sci Rep (2015)

Bottom Line: There were complex mixing sources outside and inside the Arctic Ocean.A keeling plot showed the dominant influence by hydrate gas in the Nordic Sea region, while the long range transport of wetland emissions were one of potentially important sources in the central Arctic Ocean.Experiments comparing sunlight and darkness indicate that microbes may also play an important role in regional variations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026.

ABSTRACT
The biogeochemical cycles of CH4 over oceans are poorly understood, especially over the Arctic Ocean. Here we report atmospheric CH4 levels together with δ(13)C-CH4 from offshore China (31°N) to the central Arctic Ocean (up to 87°N) from July to September 2012. CH4 concentrations and δ(13)C-CH4 displayed temporal and spatial variation ranging from 1.65 to 2.63 ppm, and from -50.34% to -44.94% (mean value: -48.55 ± 0.84%), respectively. Changes in CH4 with latitude were linked to the decreasing input of enriched δ(13)C and chemical oxidation by both OH and Cl radicals as indicated by variation of δ(13)C. There were complex mixing sources outside and inside the Arctic Ocean. A keeling plot showed the dominant influence by hydrate gas in the Nordic Sea region, while the long range transport of wetland emissions were one of potentially important sources in the central Arctic Ocean. Experiments comparing sunlight and darkness indicate that microbes may also play an important role in regional variations.

No MeSH data available.


(a) Box plots of atmospheric CH4 and (b) δ13C-CH4 at day (marked by red colour) and night (marked by black colour) over the OC, JS, NPO, BS, and CS regions. The lower and upper boundaries of the boxes represent the 25th and 75th percentiles, respectively. The lines and squares within or outside of the boxes mark the median and average values, respectively. The upper and lower asterisks signify the maximum and minimum values.
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f4: (a) Box plots of atmospheric CH4 and (b) δ13C-CH4 at day (marked by red colour) and night (marked by black colour) over the OC, JS, NPO, BS, and CS regions. The lower and upper boundaries of the boxes represent the 25th and 75th percentiles, respectively. The lines and squares within or outside of the boxes mark the median and average values, respectively. The upper and lower asterisks signify the maximum and minimum values.

Mentions: The diurnal and nocturnal CH4 concentrations and δ13C-CH4 measurements for the same sampling regions are shown in Fig. 4. Non-parametric tests revealed no significant differences between day and hight CH4 concentrations and δ13C-CH4 measurements.


δ(13)C-CH4 reveals CH4 variations over oceans from mid-latitudes to the Arctic.

Yu J, Xie Z, Sun L, Kang H, He P, Xing G - Sci Rep (2015)

(a) Box plots of atmospheric CH4 and (b) δ13C-CH4 at day (marked by red colour) and night (marked by black colour) over the OC, JS, NPO, BS, and CS regions. The lower and upper boundaries of the boxes represent the 25th and 75th percentiles, respectively. The lines and squares within or outside of the boxes mark the median and average values, respectively. The upper and lower asterisks signify the maximum and minimum values.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555175&req=5

f4: (a) Box plots of atmospheric CH4 and (b) δ13C-CH4 at day (marked by red colour) and night (marked by black colour) over the OC, JS, NPO, BS, and CS regions. The lower and upper boundaries of the boxes represent the 25th and 75th percentiles, respectively. The lines and squares within or outside of the boxes mark the median and average values, respectively. The upper and lower asterisks signify the maximum and minimum values.
Mentions: The diurnal and nocturnal CH4 concentrations and δ13C-CH4 measurements for the same sampling regions are shown in Fig. 4. Non-parametric tests revealed no significant differences between day and hight CH4 concentrations and δ13C-CH4 measurements.

Bottom Line: There were complex mixing sources outside and inside the Arctic Ocean.A keeling plot showed the dominant influence by hydrate gas in the Nordic Sea region, while the long range transport of wetland emissions were one of potentially important sources in the central Arctic Ocean.Experiments comparing sunlight and darkness indicate that microbes may also play an important role in regional variations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026.

ABSTRACT
The biogeochemical cycles of CH4 over oceans are poorly understood, especially over the Arctic Ocean. Here we report atmospheric CH4 levels together with δ(13)C-CH4 from offshore China (31°N) to the central Arctic Ocean (up to 87°N) from July to September 2012. CH4 concentrations and δ(13)C-CH4 displayed temporal and spatial variation ranging from 1.65 to 2.63 ppm, and from -50.34% to -44.94% (mean value: -48.55 ± 0.84%), respectively. Changes in CH4 with latitude were linked to the decreasing input of enriched δ(13)C and chemical oxidation by both OH and Cl radicals as indicated by variation of δ(13)C. There were complex mixing sources outside and inside the Arctic Ocean. A keeling plot showed the dominant influence by hydrate gas in the Nordic Sea region, while the long range transport of wetland emissions were one of potentially important sources in the central Arctic Ocean. Experiments comparing sunlight and darkness indicate that microbes may also play an important role in regional variations.

No MeSH data available.