Real-time measurements of CH4 and CO2 flux and del13C from a proglacial wetland in southwestern Greenland.

Abstract:

Arctic permafrost environments represent a large repository of stored carbon that may be mobilized as global temperatures increase, providing a substrate for microbial CH₄ production. Proglacial wetlands and lakes are important targets of study to better understand how rapidly changing landscapes affected by climate warming adapt their carbon cycling. Recent advances in portable laser spectrometry have enabled rapid in situ measurements of not only greenhouse gas fluxes, but also del¹³C compositions of these gases. Here we use a Picarro CH₄ and CO₂ isotope analyzer to continuously measure CH₄ and CO₂ flux in situ for comparison to static closed chamber measurements where samples are collected at discrete time intervals and returned to the laboratory for analysis. Real-time, in situ analysis also allowed simple light/dark experiments to be performed on chambers containing different vegetation. In addition, this instrument can be used to measure concentration and del¹³C of both dissolved CH₄ and CO­­₂ in lake waters when appropriate gas stripped methods are used. We present data for CH₄ and CO₂ flux and del¹³C of emitted and dissolved gases from permafrost-affected wetlands and lakes associated with proglacial landscapes in southwestern Greenland near the Russell Glacier.