Glaciology
Plant colonisation following glacial surge resulting in rapid ice loss.
The retreat of glaciers in response to climate warming in the Arctic, documented well by MOSJ (2018), exposed land surfaces for colonization by plant life and microorganisms. This process, involving environmental change and organic matter accumulation, prompted the investigation of organic carbon accumulation in freshly exposed substrates. The Bockfjorden area, with visibly retreating glaciers, provided an opportunity to assess vegetation colonization, organic matter accumulation, and greenhouse gas fluxes.
Before departure from the UK, a stratified random sampling strategy identified sample locations in and around the forefield of Adolfbreen. Spatial coordinates were determined in the field using a handheld GPS unit, and photographic records were made. Quantitative and qualitative vegetation assessments were conducted, and composite surface soil samples in the UK were analysed for gravimetric water content.
In situ gas flux measurements were made using a duplicate static chamber method in the field. Gas samples were analyzed for CO2 and CH4 using gas chromatography. The results indicated varying characteristics of moraine, tundra, and bog sites, with distinct differences in soil moisture content. CO2 fluxes did not significantly differ between tundra, moraine, and bog, but the moraine exhibited higher median CO2 fluxes. CH4 fluxes showed positive and negative values, indicating both production and consumption. Bog sites produced positive CH4 fluxes, while drier tundra sites consumed CH4.
The study concluded that freshly exposed moraine materials from glacier retreat have the capacity to exchange major greenhouse gases, with unexpected complexity in the balances of these fluxes. Moraine acted as both a sink and a source for CH4, reflecting the complexity of niches available for plant colonization, organic matter, and moisture accumulation. The microbial colonization of surface materials during glacier retreat was highlighted as particularly significant for understanding greenhouse gas balances in the high Arctic.
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