Methane (CH4) is a potent greenhouse gas contributing to the warming of Earth's atmosphere. Lakes are a natural source of CH4, where CH4 generally is produced in oxygen depleted sediments. Ebullitive CH4 is regulated naturally in the oxic-anoxic interface of lakes by methane oxidizing bacteria, methanotrophs uses CH4 as a substrate when O2 is present. Lakes in boreal regions are among the largest sources of CH4 emissions, CH4 oxidation can mitigate some of the CH4 emissions from lakes. Gaps in knowledge and data remain regarding net fluxes of CH4, indicating that there are processes unaccounted for. Previous research highlights the variability of CH4 emissions and oxidations rates in lakes, there is lacking knowledge on what drives the variability of oxidation rates and total emissions. It’s been suggested that availability of phosphorus (P) has a positive relationship with increased oxidation rates. Moreover, availability of trace elements has been suggested to affect aerobic CH4 oxidation, but there is a lack of knowledge on these factors in natural lake waters. In this study incubations with lake water from two different lakes, Gårasjön and Kisasjön, were prepared with different treatments of P and/or trace elements. We investigate how this can affect the rate of CH4 oxidation when incubated in specific conditions. Our results indicate that treatments with added P had a greater tendency to exhibit higher rates of methane oxidation in both lakes, while treatments with trace elements and P had varied oxidation rates depending on the lake. This suggests that when there are no limitations of the substrates CH4 and O2, the oxidations rates in lakes might be limited by the availability of P and the specific lake conditions can influence CH4 oxidation.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-204457 |
| Date | January 2024 |
| Creators | Lundqvist, Lexa, Unnerfelt, Saga |
| Publisher | Linköpings universitet, Tema Miljöförändring |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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