10:45 〜 11:00
[BCG05-05] Methanotrophy-mediated increase in methane emission under higher snowfall in the Arctic ecosystem
キーワード：Arctic, Methanotrophs, Nitrogen, Snow fence, Methane oxidation
The Arctic ecosystem contains vast carbon reservoirs in its soils and is undergoing rapid climate change. In addition to global warming, snowfall is projected to increase, yet its impact on methane emissions remains poorly understood. Methane, a potent greenhouse gas with a global warming potential 25 times that of carbon dioxide on a molar basis, is influenced by both biotic and abiotic factors. However, the effects of increased winter snowfall on summer methane dynamics are still elusive.
This study investigated the impact of increased snowfall using a snow fence manipulation experiment. Methane fluxes, microbial communities, and soil chemical properties were monitored to elucidate underlying mechanisms. First, a meta-analysis was conducted, synthesizing data from 42 observations across seven independent snow fence studies. Methane emissions significantly increased in studies with warming durations exceeding 10 years and temperature changes greater than 1 °C.
Second, our field experiment demonstrated significantly higher methane emissions under increased snow depth compared to control plots, despite only minor changes in soil temperature and moisture. Contrary to our initial hypothesis, no significant differences in methanogen abundance (assessed via mcrA gene quantification) were observed. However, a significant reduction in methanotroph abundance (indicated by pmoA gene quantification) was found under higher snow depth. This reduction coincided with elevated ammonium levels, which may inhibit methanotrophic activity.
Our findings reveal a previously unrecognized mechanism by which increased snowfall enhances methane emissions in Arctic ecosystems. These results have important implications for understanding biological feedbacks to global climate change.
This study investigated the impact of increased snowfall using a snow fence manipulation experiment. Methane fluxes, microbial communities, and soil chemical properties were monitored to elucidate underlying mechanisms. First, a meta-analysis was conducted, synthesizing data from 42 observations across seven independent snow fence studies. Methane emissions significantly increased in studies with warming durations exceeding 10 years and temperature changes greater than 1 °C.
Second, our field experiment demonstrated significantly higher methane emissions under increased snow depth compared to control plots, despite only minor changes in soil temperature and moisture. Contrary to our initial hypothesis, no significant differences in methanogen abundance (assessed via mcrA gene quantification) were observed. However, a significant reduction in methanotroph abundance (indicated by pmoA gene quantification) was found under higher snow depth. This reduction coincided with elevated ammonium levels, which may inhibit methanotrophic activity.
Our findings reveal a previously unrecognized mechanism by which increased snowfall enhances methane emissions in Arctic ecosystems. These results have important implications for understanding biological feedbacks to global climate change.