Sources of methane to an Arctic lake in Alaska: An isotopic investigation
| Autor: | Alanna L Lecher, Pei-Chuan Chuang, Michael J. Singleton, Adina Paytan |
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| Rok vydání: | 2017 |
| Předmět: |
Hydrology
Atmospheric Science 010504 meteorology & atmospheric sciences Ecology Paleontology Soil Science Sediment Forestry 010501 environmental sciences Aquatic Science 01 natural sciences Isotopes of oxygen Methane chemistry.chemical_compound Oceanography chemistry Isotopes of carbon Dissolved organic carbon Groundwater discharge Thaw depth Groundwater Geology 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Journal of Geophysical Research: Biogeosciences. 122:753-766 |
| ISSN: | 2169-8953 |
| DOI: | 10.1002/2016jg003491 |
| Popis: | Sources of dissolved methane (CH4) at Toolik Lake, Alaska, include both diffusion from lake sediments and groundwater entering the lake from its perimeter. Here we use hydrogen and oxygen isotopes in water (H2O), carbon and hydrogen isotopes in CH4, and carbon isotopes in dissolved inorganic carbon (DIC) to calculate the relative importance of lake sediment and groundwater discharge as sources of dissolved CH4 to Toolik Lake. We also resolve the relative importance of the source contribution spatially within the lake and determine the processes controlling CH4 concentrations in groundwater surrounding the lake. Our findings, from a mixing model based on isotopes in CH4, suggest that groundwater is a more important source of CH4 at the perimeter of the lake where the water-to-air flux is high. Additionally, we find on the local scale that high groundwater methane concentrations may be better linked to areas around the lake where rain is the dominant source of water to the active layer, indicating that changes in precipitation and active layer thaw depth will impact methane concentrations in the active layer and, ultimately, the groundwater associated flux to Toolik Lake. |
| Databáze: | OpenAIRE |
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