Permafrost thaw can lead to vegetation shifts and higher methane (CH₄) emissions in peatlands. However, plant belowground controls of these emissions are uncertain. We investigated how plant roots and rhizomes contribute to CH₄ emissions along a peatland permafrost thaw gradient. We found that low herbaceous plant root tissue density and high rhizome surface area were associated with higher CH₄ emissions. This indicated increased plant-mediated CH₄ transport with thaw.

This study provides the first evidence for biogeochemical cycling of supraglacial dissolved organic matter (DOM) in meltwater flowing through the porous crust of weathering ice that covers glacier ice surfaces during the melt season. Movement of water through the weathering crust is slow, allowing microbes and solar radiation to alter the DOM in glacial meltwaters. This is important as supraglacial meltwaters deliver DOM to downstream aquatic environments.

Outburst floods are sudden releases of water from glacial environments. As glaciers retreat, changes in glacier and basin geometry impact outburst flood characteristics. We combine a glacier flow model describing glacier retreat with an outburst flood model to explore how ice dam height, glacier length, and remnant ice in a basin influence outburst floods. We find storage capacity is the greatest indicator of flood magnitude, and the flood onset mechanism is a significant indicator of duration.