Nitrate addition has minimal short-term impacts on Greenland ice sheet supraglacial prokaryotes

Authors Organisations
Type Article
Original languageEnglish
Pages (from-to)144-150
Number of pages7
JournalEnvironmental Microbiology Reports
Volume9
Issue number2
Early online date10 Dec 2016
DOI
Publication statusPublished - 01 Apr 2017
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Abstract

Tropospheric nitrate levels are predicted to increase throughout the 21st century, with potential effects on terrestrial ecosystems, including the Greenland ice sheet (GrIS). This study considers the impacts of elevated nitrate concentrations on the abundance and composition of dominant bulk and active prokaryotic communities sampled from in situ nitrate fertilization plots on the GrIS surface. Nitrate concentrations were successfully elevated within sediment-filled meltwater pools, known as cryoconite holes; however, nitrate additions applied to surface ice did not persist. Estimated bulk and active cryoconite community cell abundance was unaltered by nitrate additions when compared to control holes using a quantitative PCR approach, and nitrate was found to have a minimal affect on the dominant 16S rRNA gene-based community composition. Together, these results indicate that sampled cryoconite communities were not nitrate limited at the time of sampling. Instead, temporal changes in biomass and community composition were more pronounced. As these in situ incubations were short (6 weeks), and the community composition across GrIS surface ice is highly variable, we suggest that further efforts should be considered to investigate the potential long-term impacts of increased nitrate across the GrIS.

Keywords

  • nitrate, fertilisation, cryoconite, ice surface, supraglacial, prokaryotes, microbial ecology, Greenland ice sheet