Multiyear measurements of ebullitive methane flux from three subarctic lakes

Ebullition (bubbling) from small lakes and ponds at high latitudes is an important yet unconstrained source of atmospheric methane (CH4). Small water bodies are most abundant in permanently frozen peatlands, and it is speculated that their emissions will increase as the permafrost thaws. We made 6806 measurements of CH4 ebullition during four consecutive summers using a total of 40 bubble traps that were systematically distributed across the depth zones of three lakes in a sporadic permafrost landscape in northernmost Sweden. We identified significant spatial and temporal variations in ebullition and observed a large spread in the bubbles\u27 CH4 concentration, ranging from 0.04% to 98.6%. Ebullition followed lake temperatures, and releases were significantly larger during periods with decreasing atmospheric pressure. Although shallow zone ebullition dominated the seasonal bubble CH4 flux, we found a shift in the depth dependency towards higher fluxes from intermediate and deep zones in early fall. The average daily flux of 13.4 mg CH4 m−2 was lower than those measured in most other high‐latitude lakes. Locally, however, our study lakes are a substantial CH4 source; we estimate that 350 kg of CH4 is released via ebullition during summer (June–September), which is approximately 40% of total whole year emissions from the nearby peatland. In order to capture the large variability and to accurately scale lake CH4 ebullition temporally and spatially, frequent measurements over long time periods are critical

Editorial Introduction: Interesting Edges on Educational Thinking

In educational spheres we find ourselves in a ‘more of the same old’ but with some new contexts for that. Taboo remains committed to finding the edges that push beyond more of the same old and embrace intersecting edges of educational thoughts and thinking that provoke thought, give fuel to our own question-making abilities, and help readers make progress in their own critically engaged journey. In 2020 we suggested that we ought to engage harder, more directly, and without fear of perspectives difficult to engage. And we continue that work in this summer 2022 issue. As we have been doing, we let the authors’ own words explain what is happening in this issue. We will list here the name and authors of each of the pieces along with their abstract. The abstracts of course appear at the start of each article, but we like having them here in the introduction to help you as a reader have agency in the decision-making you engage in when deciding how to read this issue