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

Cameron, Karen A.; Stibal, Marek; Chrismas, Nathan; Box, Jason E.; Jacobsen, Carsten Suhr

doi:10.1111/1758-2229.12510

Cited by 7 publications

(6 citation statements)

References 53 publications

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“…In comparison, the surface layer is unlikely to be subjected to nitrogen limitation, and the nitrogen in the surface snow slightly increased. This is consistent with previous studies on the Greenland ice sheet, where nitrate additions to surface ice did not alter the cryoconite community cell abundance and 16S rRNA gene-based community composition (Cameron et al, 2017).…”

Section: Rapid Shifts Of Bacterial Community Structure Across a Short...supporting

confidence: 92%

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

Chen

Liu

et al. 2022

The Cryosphere

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Abstract. The Tibetan Plateau harbors the largest number of glaciers outside the polar regions, which are the source of several major rivers in Asia. These glaciers are also major sources of nutrients for downstream ecosystems, while there is a little amount of data available on the nutrient transformation processes on the glacier surface. Here, we monitored the carbon and nitrogen concentration changes in a snowpit following a snowfall in the Dunde Glacier of the Tibetan Plateau. The association of carbon and nitrogen changes with bacterial community dynamics was investigated in the surface and subsurface snow (depth at 0–15 and 15–30 cm, respectively) during a 9 d period. Our results revealed rapid temporal changes in nitrogen (including nitrate and ammonium) and bacterial communities in both surface and subsurface snow. Nitrate and ammonium concentrations increased from 0.44 to 1.15 mg L−1 and 0.18 to 0.24 mg L−1 in the surface snow and decreased from 3.81 to 1.04 and 0.53 to 0.25 mg L−1 in the subsurface snow over time. Therefore, we suggest that the surface snow is not nitrogen-limited, while the subsurface snow is associated with nitrogen consumption processes and is nitrogen-limited. The nitrate concentration co-varied with bacterial diversity, community structure, and the predicted nitrogen fixation and nitrogen assimilation/denitrification-related genes (narG), suggesting nitrogen could mediate bacterial community changes. The nitrogen limitation and enriched denitrification-related genes in subsurface snow suggested stronger environmental and biotic filtering than those in surface snow, which may explain the lower bacterial diversity, more pronounced community temporal changes, and stronger biotic interactions. Collectively, these findings advance our understanding of bacterial community variations and bacterial interactions after snow deposition and provide a possible biological explanation for nitrogen dynamics in snow.

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Section: Rapid Shifts Of Bacterial Community Structure Across a Short...supporting

confidence: 92%

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

Chen

Liu

et al. 2022

The Cryosphere

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“…Similar conclusions have been reported in subglacial pore waters and sediments (Ren et al, 2019). In comparison, the surface layer is not subjected to nitrogen-limitation, which is consistent with previous studies in supraglacial ecosystems (Cameron et al, 2017;Holland et al, 2020).…”

Section: Nitrogen Drives the Overall Bacterial Community Structure Changes In Snowsupporting

confidence: 92%

Temporal variation in glacier snowpack bacterial communities mediated by nitrogen

Chen

Liu

et al. 2021

Preprint

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Abstract. Global warming accelerates glacier melt, releasing stored carbon and nitrogen, which fertilize downstream ecosystems. Diverse and active microbial communities mediate biogeochemical cycles in snow and are vital to the glacial ecosystem. However, little is known about their temporal changing pattern and the environmental and biotic determinants in snowpacks. Here, we investigated the bacterial community in the surface and subsurface snow (depth at 0–15 and 15–30 cm, respectively) during a nine-day period in the Dunde Glacier of the Tibetan Plateau, based on Illumina MiSeq of 16S rRNA gene sequences. Our results revealed dynamic bacterial communities in both surface and surface snow, and nitrogen is the key determinant of bacterial diversity, composition, community structure, and biotic interactions. Nitrate and ammonium concentration increased and decreased in the surface and subsurface snow over time, therefore indicating accumulation and consumption processes, respectively. This is also evidenced by the dominance of organisms predicted to carry nitrogen fixation and denitrification genes in the surface and subsurface layers, respectively. The nitrogen limitation and the apparent dominance of the denitrification in the subsurface snow suggest stronger environmental and biotic filtering than those in the surface snow. This was associated with lower bacterial diversity, more pronounced community temporal changes, and stronger biotic interactions than in the surface snow. Collectively, these findings significantly advanced our understanding of microbial community variations and bacterial interactions after snow deposition, and revealed the dynamics of nitrogen metabolism in Tibetan snow.

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“…The comparison of bulk (rDNA) and potentially active (rRNA) bacterial communities in Greenland cryoconite revealed a higher abundance of potentially active bacteria ( Cyanobacteria , Proteobacteria ) in the interior than at the margin of the ice sheet (30-km distance), while diversity was higher in the margins (Stibal et al 2015 ). Elevated nitrate levels, simulated in line with the predicted tropospheric nitrate content for the year 2100 (a 181% increase), had no significant effect on abundance and little effect on the composition of bulk or potentially active microbial communities in a 6-week in situ study using N-isotopes (Cameron et al 2017 ).…”

Section: Microbial Diversity and Activitymentioning

confidence: 98%

Microbial ecology of the cryosphere (glacial and permafrost habitats): current knowledge

Margesin

Collins

2019

Appl Microbiol Biotechnol

132

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Microorganisms in cold ecosystems play a key ecological role in their natural habitats. Since these ecosystems are especially sensitive to climate changes, as indicated by the worldwide retreat of glaciers and ice sheets as well as permafrost thawing, an understanding of the role and potential of microbial life in these habitats has become crucial. Emerging technologies have added significantly to our knowledge of abundance, functional activity, and lifestyles of microbial communities in cold environments. The current knowledge of microbial ecology in glacial habitats and permafrost, the most studied habitats of the cryosphere, is reported in this review.

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

Cited by 7 publications

References 53 publications

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

Temporal variation in glacier snowpack bacterial communities mediated by nitrogen

Microbial ecology of the cryosphere (glacial and permafrost habitats): current knowledge

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