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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.


Related in: MedlinePlus

(a) Spatial distribution of atmospheric CH4 (ppm). (b) Experimental sites for CH4 flux measurements at the short-term ice stations during CHINARE 2012. Base map is from Ocean Data View (v. 4.0, Reiner Schlitzer. Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany).
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f1: (a) Spatial distribution of atmospheric CH4 (ppm). (b) Experimental sites for CH4 flux measurements at the short-term ice stations during CHINARE 2012. Base map is from Ocean Data View (v. 4.0, Reiner Schlitzer. Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany).

Mentions: The spatial and latitudinal distributions of CH4 concentrations determined during CHINARE 2012 are shown in Figs 1a and 2a, respectively. The CH4 concentrations varied between 1.65 and 2.63 ppm. By the statistic analysis approximately 79% of the data ranged from 1.80ppm to 2.00ppm, with a median concentration of 1.88 ppm (mean: 1.88 ± 0.12 ppm), indicating that local episode influences were minimal (Fig. 2b). Based on evaluation using the Kolmogorov–Smirnov test, the CH4 concentrations were revealed to be distributed inhomogeneously along the cruise track (p < 0.05), even when the four highest values were excluded. The distribution of CH4 concentrations showed no obvious relationship with latitude outside the Arctic Ocean, which was consistent with observations from the South Atlantic13. However, the CH4 concentrations in the Arctic Ocean (>66.5°N) fluctuated in a more consistent manner, especially in the central Arctic Ocean (>80°N), where concentrations increased with latitude (r = 0.44, p < 0.01).


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) Spatial distribution of atmospheric CH4 (ppm). (b) Experimental sites for CH4 flux measurements at the short-term ice stations during CHINARE 2012. Base map is from Ocean Data View (v. 4.0, Reiner Schlitzer. Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: (a) Spatial distribution of atmospheric CH4 (ppm). (b) Experimental sites for CH4 flux measurements at the short-term ice stations during CHINARE 2012. Base map is from Ocean Data View (v. 4.0, Reiner Schlitzer. Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany).
Mentions: The spatial and latitudinal distributions of CH4 concentrations determined during CHINARE 2012 are shown in Figs 1a and 2a, respectively. The CH4 concentrations varied between 1.65 and 2.63 ppm. By the statistic analysis approximately 79% of the data ranged from 1.80ppm to 2.00ppm, with a median concentration of 1.88 ppm (mean: 1.88 ± 0.12 ppm), indicating that local episode influences were minimal (Fig. 2b). Based on evaluation using the Kolmogorov–Smirnov test, the CH4 concentrations were revealed to be distributed inhomogeneously along the cruise track (p < 0.05), even when the four highest values were excluded. The distribution of CH4 concentrations showed no obvious relationship with latitude outside the Arctic Ocean, which was consistent with observations from the South Atlantic13. However, the CH4 concentrations in the Arctic Ocean (>66.5°N) fluctuated in a more consistent manner, especially in the central Arctic Ocean (>80°N), where concentrations increased with latitude (r = 0.44, p < 0.01).

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.


Related in: MedlinePlus