Seasonal snowpack microbial ecology and biogeochemistry on a High Arctic ice cap reveals negligible autotrophic activity during spring and summer melt

Dayal, Archana; Hodson, Andrew J.; Šabacká, Marie; Smalley, Alan

doi:10.1002/essoar.10512386.1

Cited by 2 publications

(8 citation statements)

References 33 publications

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“…Foxfonna (78.14° N 16.11° E) is a 6 km 2 sized ice cap with a north‐facing outlet glacier (hereafter Lower Foxfonna ) in Central Spitsbergen, Svalbard. Previous studies on Foxfonna have addressed the molecular ecology (Gokul et al, 2016; Gokul et al, 2023), biogeochemistry (Dayal et al, 2023; Koziol et al, 2019) and supraglacial processes (Irvine‐Fynn et al, 2022). Predominantly cold glacier ice extends from ~380 to 810 m above sea level with a maximum thickness of ~60 m in the upper elevations, but extending to ~120 m in Lower Foxfonna (Christiansen et al, 2005; Rutter et al, 2011).…”

Section: Methodsmentioning

confidence: 99%

The distinctive weathering crust habitat of a High Arctic glacier comprises discrete microbial micro‐habitats

Rassner,

Cook,

Mitchell

et al. 2024

Environmental Microbiology

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Sunlight penetrates the ice surfaces of glaciers and ice sheets, forming a water‐bearing porous ice matrix known as the weathering crust. This crust is home to a significant microbial community. Despite the potential implications of microbial processes in the weathering crust for glacial melting, biogeochemical cycles, and downstream ecosystems, there have been few explorations of its microbial communities. In our study, we used 16S rRNA gene sequencing and shotgun metagenomics of a Svalbard glacier surface catchment to characterise the microbial communities within the weathering crust, their origins and destinies, and the functional potential of the weathering crust metagenome. Our findings reveal that the bacterial community in the weathering crust is distinct from those in upstream and downstream habitats. However, it comprises two separate micro‐habitats, each with different taxa and functional categories. The interstitial porewater is dominated by Polaromonas, influenced by the transfer of snowmelt, and exported via meltwater channels. In contrast, the ice matrix is dominated by Hymenobacter, and its metagenome exhibits a diverse range of functional adaptations. Given that the global weathering crust area and the subsequent release of microbes from it are strongly responsive to climate projections for the rest of the century, our results underscore the pressing need to integrate the microbiome of the weathering crust with other communities and processes in glacial ecosystems.

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Section: Methodsmentioning

confidence: 99%

The distinctive weathering crust habitat of a High Arctic glacier comprises discrete microbial micro‐habitats

Rassner,

Cook,

Mitchell

et al. 2024

Environmental Microbiology

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“…These stakes have reported sustained mass balance decline since 2008 (Hodson, Unpublished Data). The study described here was conducted during 2016, after a strong winter accumulation that was followed by a high ablation rate that resulted in almost complete snow cover removal from the entire ice cap by the end of the summer (Dayal et al, 2023).…”

Section: Study Sitementioning

confidence: 99%

“…Field sampling was undertaken to coincide with key periods in the seasonal evolution of the snow cover (Dayal et al, 2023). These periods are summarised in Table 1.…”

Section: Snow Pit Samplingmentioning

confidence: 99%

“…At each of the seven stakes, the following samples were collected monthly into sterile Whirl-pak (Nasco) bags using a sterile graduated cylinder: surface snow (0-20 cm depth), mid snow (from 20 cm depth to the base of the snowpack), refrozen snowmelt superimposed upon the glacier ice at the base of the snowpack. These samples are hereafter referred to as "TOP", "MID" and "SUP ICE" respectively, whilst "GL ICE" refers to the uppermost 25 cm of glacier ice extracted at each stake during the early and late July surveys only (refer to Dayal et al, 2023 for further sampling details). Snowpack was dry with no melt water production.…”

Section: Snow Pit Samplingmentioning

confidence: 99%

“…After June, snowmelt percolation and re-freezing formed ice lenses within the snow and superimposed ice at its interface with the underlying glacier. The latent heat release and other energy sources at this time of year bring the entire snowpack to the melting point, such that water becomes increasingly mobile and abundant within the snowpack (Dayal et al, 2023). Cell concentrations in early July snow cover (averaged at each stake) were therefore compared with those in superimposed ice and surface glacier ice.…”

Section: Vertical Differences In Cell Concentrations Within the Snowpackmentioning

confidence: 99%

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Seasonal changes in the viability of bacterial cells in the snowpack ecosystem of a High Arctic ice cap

Dayal,

Hodson,

Šabacká

et al. 2023

Preprint

Self Cite

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We present an in-depth analysis of the proportions of potentially “viable” and “non-viable” bacterial cell populations within the different layers of a melting snowpack on a High Arctic ice cap, Foxfonna in Svalbard. To do so, we employed the SYBR-PI dual cell stain to both flow cytometry and epifluorescence microscopy for enumeration. Non-viable cells soon dominated on Foxfonna (2.5 ± 0.36 x 107 cells m− 2) during the June to early July period, when biological production is expected to be greatest. Moreover, non-viable cells also dominated total cell abundance within superimposed ice (223 ± 242 cells mL− 1) and glacial ice (695 ± 717 cells mL− 1) beneath the snow. As a result, bacterial production on the ice cap caused the proliferation of ‘potentially non-viable cells’ as early as mid-July. We propose that the rapid, early loss of cell viability was caused by abiotic and biotic factors, with UV damage and viral lysis being most plausible. Dead cell residue (necromass) therefore contributes to organic matter export, although in late July we also found a far more significant input from other detrital sources, most likely dust. The export of organic matter from ice caps as their snow cover is transformed into meltwater runoff is therefore derived from both autochthonous and allochthonous sources, but with limited viable bacteria.

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Seasonal snowpack microbial ecology and biogeochemistry on a High Arctic ice cap reveals negligible autotrophic activity during spring and summer melt

Cited by 2 publications

References 33 publications

The distinctive weathering crust habitat of a High Arctic glacier comprises discrete microbial micro‐habitats

The distinctive weathering crust habitat of a High Arctic glacier comprises discrete microbial micro‐habitats

Seasonal changes in the viability of bacterial cells in the snowpack ecosystem of a High Arctic ice cap

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