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- Keuschnig, Christoph, et al.
(author)
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Selection processes of Arctic seasonal glacier snowpack bacterial communities
- 2023
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In: Microbiome. - : BioMed Central (BMC). - 2049-2618. ; 11:1
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Journal article (peer-reviewed)abstract
- BackgroundArctic snowpack microbial communities are continually subject to dynamic chemical and microbial input from the atmosphere. As such, the factors that contribute to structuring their microbial communities are complex and have yet to be completely resolved. These snowpack communities can be used to evaluate whether they fit niche-based or neutral assembly theories.MethodsWe sampled snow from 22 glacier sites on 7 glaciers across Svalbard in April during the maximum snow accumulation period and prior to the melt period to evaluate the factors that drive snowpack metataxonomy. These snowpacks were seasonal, accumulating in early winter on bare ice and firn and completely melting out in autumn. Using a Bayesian fitting strategy to evaluate Hubbell’s Unified Neutral Theory of Biodiversity at multiple sites, we tested for neutrality and defined immigration rates at different taxonomic levels. Bacterial abundance and diversity were measured and the amount of potential ice-nucleating bacteria was calculated. The chemical composition (anions, cations, organic acids) and particulate impurity load (elemental and organic carbon) of the winter and spring snowpack were also characterized. We used these data in addition to geographical information to assess possible niche-based effects on snow microbial communities using multivariate and variable partitioning analysis.ResultsWhile certain taxonomic signals were found to fit the neutral assembly model, clear evidence of niche-based selection was observed at most sites. Inorganic chemistry was not linked directly to diversity, but helped to identify predominant colonization sources and predict microbial abundance, which was tightly linked to sea spray. Organic acids were the most significant predictors of microbial diversity. At low organic acid concentrations, the snow microbial structure represented the seeding community closely, and evolved away from it at higher organic acid concentrations, with concomitant increases in bacterial numbers.ConclusionsThese results indicate that environmental selection plays a significant role in structuring snow microbial communities and that future studies should focus on activity and growth.
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| 2. |
- Petäjä, Tuukka, et al.
(author)
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Overview : Integrative and Comprehensive Understanding on Polar Environments (iCUPE) - concept and initial results
- 2020
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In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:14, s. 8551-8592
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Journal article (peer-reviewed)abstract
- The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project iCUPE - integrative and Comprehensive Understanding on Polar Environments to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining in situ observations, satellite remote sensing Earth observations (EOs), and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns, and satellites to deliver data products, metrics, and indicators to stakeholders concerning the environmental status, availability, and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and the provision of novel data in atmospheric pollution, local sources and transboundary transport, the characterization of arctic surfaces and their changes, an assessment of the concentrations and impacts of heavy metals and persistent organic pollutants and their cycling, the quantification of emissions from natural resource extraction, and the validation and optimization of satellite Earth observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of the integration of comprehensive in situ observations, satellite remote sensing, and multi-scale modeling in the Arctic context.
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| 3. |
- Spolaor, Andrea, et al.
(author)
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Climate change is rapidly deteriorating the climatic signal in Svalbard glaciers
- 2024
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In: CRYOSPHERE. - 1994-0416 .- 1994-0424. ; 18:1, s. 307-320
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Journal article (peer-reviewed)abstract
- The Svalbard archipelago is particularly sensitive to climate change due to the relatively low altitude of its main ice fields and its geographical location in the higher North Atlantic, where the effect of Arctic amplification is more significant. The largest temperature increases have been observed during winter, but increasing summer temperatures, above the melting point, have led to increased glacier melt. Here, we evaluate the impact of this increased melt on the preservation of the oxygen isotope ( delta 18 O) signal in firn records. delta 18 O is commonly used as a proxy for past atmospheric temperature reconstructions, and, when preserved, it is a crucial parameter to date and align ice cores. By comparing four different firn cores collected in 2012, 2015, 2017 and 2019 at the top of the Holtedahlfonna ice field (1100 m a.s.l.), we show a progressive deterioration of the isotope signal, and we link its degradation to the increased occurrence and intensity of melt events. Our findings indicate that, starting from 2015, there has been an escalation in melting and percolation resulting from changes in the overall atmospheric conditions. This has led to the deterioration of the climate signal preserved within the firn or ice. Our observations correspond with the model's calculations, demonstrating an increase in water percolation since 2014, potentially reaching deeper layers of the firn. Although the delta 18 O signal still reflects the interannual temperature trend, more frequent melting events may in the future affect the interpretation of the isotopic signal, compromising the use of Svalbard ice cores. Our findings highlight the impact and the speed at which Arctic amplification is affecting Svalbard's cryosphere.
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| 5. |
- Zdanowicz, Christian, 1966-, et al.
(author)
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Strategies and Best Practices for Monitoring Seasonal Snow Cover Composition
- 2019
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Conference paper (other academic/artistic)abstract
- Seasonal snow covers up to 45 million km^2 every winter. As such, it represents a major interface between the Earth's surface and atmosphere. It also offers a convenient sampling medium to monitor water isotopes in solid precipitation and the net deposition of a wide variety of atmospheric species, including nutrients, organic compounds (OCs), trace metals, dust, black carbon (BC), and many others. Impurities such as dust and BC are light-absorbing and as such can modify the radiative properties of snow, while other atmospheric species such as OCs or certain metals can adversely affect the aquatic environment and drinking water quality in meltwater-fed basins. Systematic monitoring of seasonal snowpack composition may therefore offer a way of supplementing direct observations of air and precipitation chemistry. It may also lend itself well to certain "citizen science" activities, provided a set of standardized protocols can be adopted, and an adequate platform for data collection and sharing be established. In recent years, some recommendations to this effect were made by the snow science community through the IASC Cryosphere Working Group, the WMO Global Cryosphere Watch and EU Harmosnow initiative. The purpose of this presentation is to stimulate a continued discussion of the merits, challenges and caveats of establishing a network of coordinated snowpack composition observations. Examples of existing or recently-developed monitoring protocols for snowpacks in Arctic and montane regions will be presented and discussed.
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