Greenhouse gases in Siberian ice cores
Greenhouse effect as global warming is becoming a hot topic in scientific world as well as in the society since the world sees plenty of changes in weather and environment. Thawing permafrost in Siberia covering 25% of Northern Hemisphere occurs gradually and releases potent greenhouse gases, such a...
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| Format: | Thesis |
| Language: | unknown |
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2018
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| Online Access: | https://epic.awi.de/id/eprint/47065/ https://hdl.handle.net/10013/epic.6d2aa37c-ddae-4688-af50-66c3b26d9c5c |
| Summary: | Greenhouse effect as global warming is becoming a hot topic in scientific world as well as in the society since the world sees plenty of changes in weather and environment. Thawing permafrost in Siberia covering 25% of Northern Hemisphere occurs gradually and releases potent greenhouse gases, such as methane and carbon dioxide. The role of ice in Siberian lakes and bays is an important but rather unknown aspect in the turnover cycles of these greenhouse gases. In spring 2017 during the Bykovski expedition to Lena Delta, Siberia, ice cores were drilled in the ice as well as water samples below the ice. These ice cores were used to investigate the concentration profiles of the greenhouse gases (CH4, CO2, N2O) and CO in different layers of the ice. In the laboratory, the method to determine these gases with a gas chromatograph had to be optimized. A flame ionization detector with methanizer was used to determine CH4, CO2 and CO. For N2O an electron capture detector was used. Also, different methods to extract the gases from the ice cores were compared. Highest methane concentrations were mostly found in the bottom ice layer, with even higher concentrations in the water column. In Lake Goltsovoye, CH4 seemed to accumulate in the middle of the lake. Methane concentrations in the lagoon were comparable with the freshwater lake. However, the “Polar fox lake” with its saltwater revealed highest concentrations of methane. The other gases (CO, CO2, and N2O) revealed no differences between the different water bodies and ice cores. We conclude that during winter methane accumulate below the ice and diffuses into the bottom ice layers. At sites with high methane concentrations, methane was also observed in high concentration in the top ice layers, and thus may also reach the atmosphere during winter. The methane trapped under the ice and within the bottom layers probably will be released during spring melt. |
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