Variations in Phototroph Communities on the Ablating Bare-Ice Surface of Glaciers on Brøggerhalvøya, Svalbard

Nozomu Takeuchi,Tristram D L Irvine-Fynn,Yudai Konno,Sara M E Rassner,Sota Tanaka,Arwyn Edwards

doi:10.3389/feart.2019.00004

Nozomu Takeuchi, Tristram D L Irvine-Fynn + Show 4 more

Open Access

https://doi.org/10.3389/feart.2019.00004

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Abstract

During the summer ablation season, Arctic glacier surfaces host a wealth of microbial life. Here, the phototroph communities on the ablating bare-ice surface of three valley glaciers on Broggerhalvoya, Svalbard were investigated. The communities mainly comprised seven taxa of green algae and cyanobacteria, which have been commonly reported on Arctic glaciers. Although the geographical and glaciological settings of the three studied glaciers are similar, there were differences in total phototroph biomass. The community structure was also distinctive among the glaciers: high dominance of a single taxon of green algae (Ancylonema nordenskioldii) for Midtre Lovenbreen, abundant cyanobacteria for Austre Broggerbreen, and diverse green algae for Pedersenbreen. The major soluble ions in the surface ice showed that there was no significant difference in meltwater nutrient conditions between the glaciers, but there were lower concentrations of mineral-derived ions on Midtre Lovenbreen. Consequently, the glacier-specific mineral loading and surface hydrology are inferred to explain the contrast in bare ice algal communities between the glaciers. We hypothesise that local, glacier-specific conditions affect algal communities and the associated influences on carbon cycling and ice-surface albedo.

Highlights

Within the Earth system, glaciers and ice sheets are an important microbe-dominated ecosystem (Hodson et al, 2008), harboring an estimated 1029 microbes (Irvine-Fynn and Edwards, 2014)
In response to its geometry and recent thinning, Austre Brøggerbreen has a drainage system that is more interrupted by moulins and crevasse traces (Jennings et al, 2016), while in contrast, Midtre Lovénbreen is characterized by a number of deeply incised parallel supraglacial channels fed by dendritic rill networks that extend over the majority of the glacier’s ablation area (Rippin et al, 2015; Figure 7b) and Pedersenbreen exhibits a more dense drainage pattern associated with ice structure oriented downglacier but oblique to the centerline (Figure 7c)
The community was characterized by the greater total biomass and high dominance of single green algae A. nordenskiöldii for Midtre Lovénbreen, by dominance of cyanobacteria for Austre Brøggerbreen, and by composition of diverse green algae for Pedersenbreen

Summary

Introduction

Within the Earth system, glaciers and ice sheets are an important microbe-dominated ecosystem (Hodson et al, 2008), harboring an estimated 1029 microbes (Irvine-Fynn and Edwards, 2014). The total cell volume biomass significantly varied among the study sites

Results

Conclusion