Article

Biogeochemistry

, Volume 78, Issue 2, pp 173-193

First online:

Chemical and Isotopic Switching within the Subglacial Environment of a High Arctic Glacier

  • Peter M. WynnAffiliated withDepartment of Geography, University Of SheffieldSchool of Geography, Earth and Environmental Sciences, University of Birmingham Email author 
  • , Andrew HodsonAffiliated withDepartment of Geography, University Of Sheffield
  • , Tim HeatonAffiliated withDepartment of Geography, University Of Sheffield

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Abstract

Natural environmental isotopes of nitrate, sulphate and inorganic carbon are discussed in conjunction with major ion chemistry of subglacial runoff from a High Arctic glacier, Midre Lovénbreen, Svalbard. The chemical composition of meltwaters is observed to switch in accordance with subglacial hydrological evolution and redox status. Changing rapidly from reducing to oxidizing conditions, subglacial waters also depict that 15N/14N values show microbial denitrification is an active component of nutrient cycling beneath the glacier. 18O/16O ratios of sulphate are used to elucidate mechanisms of biological and abiological sulphide oxidation. Concentrations of bicarbonate appear to be governed largely by the degree of rock: water contact encountered in the subglacial system, rather than the switch in redox status, although the potential for microbiological activity to influence ambient bicarbonate concentrations is recognised. Glaciers are therefore highlighted as cryospheric ecosystems supporting microbial life which directly impacts upon the release of solute through biogeochemically mediated processes.

Keywords

Isotopes Major ion chemistry Microbial Redox status Subglacial