The biogeochemistry of subglacial systems
Abstract
Subglacial environments can contain some of the highest concentrations of sediment, solutes, nutrients, and microbes found in glacier systems, and can play a fundamental role in defining the biogeochemistry of the meltwater discharged into downstream ecosystems and of the material released into glacier forefields. Subglacial environments are permanently dark and are in close proximity to the underlying substrate. They are characterized by spatial and temporal variability in rates of erosion and rock weathering, ice temperature, the availability of water and atmospheric gases and, ultimately, rates and pathways of microbial activity and nutrient cycling . Research efforts continue to resolve how geological, hydrological, and glaciological factors influence subglacial biogeochemistry, to constrain our understanding of the processes that occur, and to quantify the biogeochemical heterogeneity that exists within these systems. Recent observations of basal ice from polythermal and cold-based glaciers in the Canadian Arctic continue this effort and suggest that basal thermal regime exerts a primary control on the extent to which glaciers mobilize material from the underlying substrate and on the extent and type of biogeochemical activity that can occur within the subglacial system. Pooled water that resides in the subglacial system of polythermal glaciers over winter can show evidence of in situ biogeochemical activity that may selectively deplete its reservoir of labile dissolved nutrients. Findings from this research help constrain the mix of solutes, nutrients, and microbes that can be acquired from substrates beneath glaciers, produced within subglacial environments, and exported into downstream ecosystems under a changing climate.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB086...01D
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0465 Microbiology: ecology;
- physiology and genomics;
- BIOGEOSCIENCES;
- 0475 Permafrost;
- cryosphere;
- and high-latitude processes;
- BIOGEOSCIENCES