Investigating Carbon, Nutrient and Methane Dynamics in Proglacial Lakes: Study Design and Objectives for the Southwestern Greenland Campaign

Abstract

Methane, a potent greenhouse gas, is increasingly recognized to be emitted from newly deglaciated environments, particularly in the Arctic, yet due to data scarcity these sources remain underrepresented in global methane budgets. Deglaciation leads to the expansion of proglacial terrains, driving the formation of an increasing number of proglacial lakes worldwide, especially in Greenland. Small to medium sized glacial lakes, formed through (post-) glacial processes, typically contain organic-poor minerogenic sediments and exhibit relatively low diffusive and ebullitive methane emissions compared to other types of Arctic lakes. However, recent evidence from Southwest (SW) Greenland suggests that glacier-fed lakes may produce disproportionally high methane ebullition fluxes compared to glacial lakes that are hydrologically disconnected from glacial meltwaters. It is hypothesized that glacially derived sediments and meltwaters influence the biogeochemistry of glacier-fed lakes, altering methane production dynamics. From March 31st to April 22nd, 2025, field sampling will be conducted in the ice-marginal terrain near Kangerlussuaq, SW Greenland. The study will involve lake sediment coring, geo- and hydrochemical analysis and gas measurements to investigate carbon sources, microbial communities and nutrient cycling in relation to methane production in proglacial lake environments. As the number of glacier-fed lakes continue to increase, there is a growing need to understand methane emissions from these systems. The findings of this research are expected to identify key drivers of methane production, reduce uncertainties in global methane budgets, and improve predictions of the potential significance of methane emissions from proglacial lakes as deglaciation continues.