scholarly journals Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

2016 ◽  
Vol 82 (6) ◽  
pp. 1868-1880 ◽  
Author(s):  
Miriam Marquardt ◽  
Anna Vader ◽  
Eike I. Stübner ◽  
Marit Reigstad ◽  
Tove M. Gabrielsen
Keyword(s):  
454 Sequencing ◽  
High Arctic ◽  
Early Spring ◽  
Small Cells ◽  
The Arctic ◽  
Content Type ◽  
Dna And Rna ◽  
Microbial Eukaryotes ◽  
West Spitsbergen ◽  
Extreme Seasonality

ABSTRACTThe Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 μm) from a depth of 25 m was determined using 454 sequencing of the 18S V4 region amplified from both DNA and RNA. The compositional changes throughout the year were assessed in relation toin situfjord environmental conditions. Size fractionation analyses of chlorophyllashowed that the photosynthetic biomass was dominated by small cells (<10 μm) most of the year but that larger cells dominated during the spring and summer. The winter and early-spring communities were more diverse than the spring and summer/autumn communities. Dinophyceae were predominant throughout the year. The ArcticMicromonasecotype was abundant mostly in the early-bloom and fall periods, whereas heterotrophs, such as marine stramenopiles (MASTs), Picozoa, and the parasitoid marine alveolates (MALVs), displayed higher relative abundance in the winter than in other seasons. Our results emphasize the extreme seasonality of Arctic microbial eukaryotic communities driven by the light regime and nutrient availability but point to the necessity of a thorough knowledge of hydrography for full understanding of their succession and variability.

scholarly journals Metagenomic Analysis of Stress Genes in Microbial Mat Communities from Antarctica and the High Arctic

2011 ◽  
Vol 78 (2) ◽  
pp. 549-559 ◽  
Author(s):  
Thibault Varin ◽  
Connie Lovejoy ◽  
Anne D. Jungblut ◽  
Warwick F. Vincent ◽  
Jacques Corbeil
Keyword(s):  
High Arctic ◽  
Environmental Stresses ◽  
The Arctic ◽  
Functional Responses ◽  
Protein Coding ◽  
Content Type ◽  
Stress Genes ◽  
Cyanobacterial Genes ◽  
Shock Proteins ◽  
The Antarctic

ABSTRACTPolar and alpine microbial communities experience a variety of environmental stresses, including perennial cold and freezing; however, knowledge of genomic responses to such conditions is still rudimentary. We analyzed the metagenomes of cyanobacterial mats from Arctic and Antarctic ice shelves, using high-throughput pyrosequencing to test the hypotheses that consortia from these extreme polar habitats were similar in terms of major phyla and subphyla and consequently in their potential responses to environmental stresses. Statistical comparisons of the protein-coding genes showed similarities between the mats from the two poles, with the majority of genes derived fromProteobacteriaandCyanobacteria; however, the relative proportions differed, with cyanobacterial genes more prevalent in the Antarctic mat metagenome. Other differences included a higher representation ofActinobacteriaandAlphaproteobacteriain the Arctic metagenomes, which may reflect the greater access to diasporas from both adjacent ice-free lands and the open ocean. Genes coding for functional responses to environmental stress (exopolysaccharides, cold shock proteins, and membrane modifications) were found in all of the metagenomes. However, in keeping with the greater exposure of the Arctic to long-range pollutants, sequences assigned to copper homeostasis genes were statistically (30%) more abundant in the Arctic samples. In contrast, more reads matching the sigma B genes were identified in the Antarctic mat, likely reflecting the more severe osmotic stress during freeze-up of the Antarctic ponds. This study underscores the presence of diverse mechanisms of adaptation to cold and other stresses in polar mats, consistent with the proportional representation of major bacterial groups.

The Importance of Mineral Dust and Proteinaceous Ice Nucleating Particles in the Canadian High Artic During the Fall of 2018 

2021 ◽  
Author(s):  
Jingwei Yun ◽  
Erin Evoy ◽  
Soleil Worthy ◽  
Melody Fraser ◽  
Daniel Veber ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Mineral Dust ◽  
Dispersion Model ◽  
High Arctic ◽  
Particle Dispersion ◽  
Early Spring ◽  
The Arctic ◽  
Ice Formation ◽  
Back Trajectory ◽  
Early Fall

&lt;p&gt;Ice nucleating particles (INPs) can initiate ice formation in clouds, which has a large impact on the hydrological cycle and radiative budget of the Earth. Constraints on the concentration and composition of INPs are needed to predict ice formation in clouds and hence the climate. Despite previous INP measurements in the Arctic, our understanding of the concentrations, composition, and sources of Arctic INPs is insufficient. Here we report daily concentrations of INPs at Alert, a ground site in the Canadian High Arctic, during October and November of 2018. The contributions of mineral dust and proteinaceous particles to the total INP population were evaluated by testing the responses of the samples to heat and ammonium treatments. Possible source locations of the most effective INPs were investigated using back-trajectory simulations with a Lagrangian particle dispersion model. The results show that the INP concentrations in October were higher than that in November. Combining our results with previous INP measurements at Alert, a seasonal trend was observed for the INP concentrations at -18 &amp;#176;C and -22 &amp;#176;C, with a higher concentration in the late spring, summer and early fall, and a lower concentration in the early spring, late fall, and winter. For the October samples, proteinaceous INPs were detected at T &gt; -21 &amp;#176;C with a fraction of 60% to 100% and mineral dust INPs were detected at T &lt; -21 &amp;#176;C. For the November samples, proteinaceous INPs were only detected at T &gt; -16 &amp;#176;C with a fraction of 88% to 100% and mineral dust INPs were detected at T &lt; -20 &amp;#176;C. The most effective INPs were possibly from South China and California based on 20-day backward simulations using the FLEXible PARTicle dispersion model and the correlations between INP concentrations and Al, , Na&lt;sup&gt;+&lt;/sup&gt;, and Cl&lt;sup&gt;-&lt;/sup&gt; measured at the site.&amp;#160;&amp;#160;&lt;/p&gt;

scholarly journals Sources of anions in aerosols in northeast Greenland during late winter

2012 ◽  
Vol 12 (6) ◽  
pp. 14813-14836 ◽  
Author(s):  
M. Fenger ◽  
L. L. Sørensen ◽  
K. Kristensen ◽  
B. Jensen ◽  
Q. T. Nquyen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Long Range ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Chemical Properties ◽  
High Arctic ◽  
Early Spring ◽  
Water Soluble ◽  
The Arctic ◽  
Late Winter

Abstract. The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes affecting the composition of the aerosols in the high Arctic. Therefore size-segregated aerosols were sampled at a high Arctic site, Station Nord (Northeast Greenland), in March 2009 using a Micro Orifice Uniform Deposit Impactor. The aerosol samples were extracted in order to analyze the three water-soluble anions: chloride, nitrate and sulphate. The results are discussed based on possible chemical and physical transformations as well as transport patterns. The total concentrations of the ions at Station Nord were 53–507 ng m−3, 2–298 ng m−3 and 535–1087 ng m−3 for chloride (Cl−), nitrate (NO3-) and sulphate (SO42−), respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO42−, Cl− and NO3−, are hypothesized to originate from long-range transport, where SO42− is by far the dominating anion accounting for 50–85% of the analyzed mass. The analysis suggests that Cl− and NO3− in coarser particles (>1.5 μm) originate from local/regional sources. Under conditions where the air mass is transported over sea-ice at high wind speeds, very coarse particles (>18 μm) are observed and it is hypothesized that frost flowers on the sea ice is a source of very coarse chloride particles in the Arctic.

scholarly journals Microbes in High Arctic Snow and Implications for the Cold Biosphere

2011 ◽  
Vol 77 (10) ◽  
pp. 3234-3243 ◽  
Author(s):  
Tommy Harding ◽  
Anne D. Jungblut ◽  
Connie Lovejoy ◽  
Warwick F. Vincent
Keyword(s):  
Microbial Mats ◽  
High Arctic ◽  
Small Subunit ◽  
Transport Processes ◽  
The Arctic ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Content Type ◽  
Ssu Rrna Gene ◽  
Aerial Transport

ABSTRACTWe applied molecular, microscopic, and culture techniques to characterize the microbial communities in snow and air at remote sites in the Canadian High Arctic (Ward Hunt Island, Ellesmere Island, and Cornwallis Island, latitudes 74 to 83oN). Members of theBacteriaandEukaryawere prevalent in the snow, and their small subunit (SSU) rRNA gene signatures indicated strong local aerial transport within the region over the preceding 8 months of winter snowpack accumulation. Many of the operational taxonomic units (OTUs) were similar to previously reported SSU rRNA gene sequences from the Arctic Ocean, suggesting the importance of local aerial transport processes for marine microbiota. More than 47% of the cyanobacterial OTUs in the snow have been previously found in microbial mats in the region, indicating that this group was also substantially derived from local sources. Viable cyanobacteria isolated from the snow indicated free exchange between the snow and adjacent mat communities. Other sequences were most similar to those found outside the Canadian Arctic but were from snow, lake and sea ice, glaciers and permafrost, alpine regions, Antarctica, and other regions of the Arctic, supporting the concept of global distribution of microbial ecotypes throughout the cold biosphere.

scholarly journals Thermo-hydrological Responses to an Exceptionally Warm, Dry Summer in a High Arctic Environment

2003 ◽  
Vol 34 (1-2) ◽  
pp. 51-70 ◽  
Author(s):  
Kathy L. Young ◽  
Ming-ko Woo
Keyword(s):  
High Arctic ◽  
Early Spring ◽  
The Arctic ◽  
Degree Days ◽  
Short Term ◽  
Hydrological Responses ◽  
Hydrologic Systems ◽  
Top Soil ◽  
Warm Summer ◽  
Cornwallis Island

1998 was a very warm year for Canada and the High Arctic was no exception. A typical area was Resolute, Cornwallis Island, Nunavut, where the thaw season was extended and the thawing degree-days were larger than normal. The warm summer was accompanied by early spring melt and low rainfall. This study documents the thermo-hydrological responses including warming of the top soil, deepening of the active layer, alteration of the evaporation pattern, adjustment of the water table positions and runoff. The presence of semi-permanent snowbanks and patchy wetlands buffer some local sites from the warm and dry summer conditions. This and other studies show that the cryospheric and hydrologic systems may or may not recover quickly from the year to year variations in the climate, depending on how readily the storages (snow, ice and basin moisture) can be replenished. In view of the cumulative effects of storage depletion under climatic warming, short-term studies on thermo-hydrological behaviour in the Arctic provide a useful but insufficient analogue to capture the climatic change impacts.

scholarly journals Genome Sequence of the Arctic Methanotroph Methylobacter tundripaludum SV96

2011 ◽  
Vol 193 (22) ◽  
pp. 6418-6419 ◽  
Author(s):  
Mette M. Svenning ◽  
Anne Grethe Hestnes ◽  
Ingvild Wartiainen ◽  
Lisa Y. Stein ◽  
Martin G. Klotz ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Oxides ◽  
Novel Species ◽  
High Arctic ◽  
Nitrite Reduction ◽  
The Arctic ◽  
Wetland Soil ◽  
Content Type ◽  
Genome Data ◽  
Major Player

Methylobacter tundripaludum SV96 T (ATCC BAA-1195) is a psychrotolerant aerobic methane-oxidizing gammaproteobacterium ( Methylococcales , Methylococcaceae ) living in High Arctic wetland soil. The strain was isolated from soil harvested in July 1996 close to the settlement Ny-Ålesund, Svalbard, Norway (78°56′N, 11°53′E), and described as a novel species in 2006. The genome includes pmo and pxm operons encoding copper membrane monooxygenases (Cu-MMOs), genes required for nitrogen fixation, and the nirS gene implicated in dissimilatory nitrite reduction to NO but no identifiable inventory for further processing of nitrogen oxides. These genome data provide the basis to investigate M. tundripaludum SV96, identified as a major player in the biogeochemistry of Arctic environments.

scholarly journals Sources of anions in aerosols in northeast Greenland during late winter

2013 ◽  
Vol 13 (3) ◽  
pp. 1569-1578 ◽  
Author(s):  
M. Fenger ◽  
L. L. Sørensen ◽  
K. Kristensen ◽  
B. Jensen ◽  
Q. T. Nguyen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Long Range ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Chemical Properties ◽  
High Arctic ◽  
Early Spring ◽  
Water Soluble ◽  
The Arctic ◽  
Late Winter

Abstract. The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes affecting the composition of aerosols in the high Arctic. Therefore size-segregated aerosols were sampled at a high Arctic site, Station Nord (Northeast Greenland), in March 2009 using a Micro Orifice Uniform Deposit Impactor. The aerosol samples were extracted in order to analyse three water-soluble anions: chloride, nitrate and sulphate. The results are discussed based on possible chemical and physical transformations as well as transport patterns. The total concentrations of the ions at Station Nord were 53–507 ng m−3, 2–298 ng m−3 and 535–1087 ng m−3 for chloride (Cl−), nitrate (NO3−) and sulphate (SO42−), respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO42−, Cl− and NO3−, are hypothesized to originate from long-range transport, where SO42− is by far the dominating anion accounting for 50–85% of the analyzed mass. The analysis suggests that Cl− and NO3− in coarser particles (> 1.5 μm) originate from local/regional sources. Under conditions where the air mass is transported over sea ice at high wind speeds, very coarse particles (> 18 μm) are observed, and it is hypothesized that frost flowers on the sea ice are a source of the very coarse nitrate particles.

scholarly journals Linking extreme seasonality and gene expression in arctic marine protists

2021 ◽  
Author(s):  
Magdalena Wutkowska ◽  
Anna Vader ◽  
Ramiro Logares ◽  
Eric Pelletier ◽  
Tove M. Gabrielsen
Keyword(s):  
Gene Expression ◽  
Light Availability ◽  
High Arctic ◽  
Polar Night ◽  
Microbial Eukaryotes ◽  
Seasonal Impact ◽  
Polar Day ◽  
Arctic Fjord ◽  
Marine Protists ◽  
Extreme Seasonality

At high latitudes, strong seasonal differences in light availability affect marine organisms and restrict the timing of ecosystem processes. Marine protists are key players in Arctic aquatic ecosystems, yet little is known about their ecological roles over yearly cycles. This is especially true for the dark polar night period, which up until recently was assumed to be devoid of biological activity. A 12 million transcripts catalogue was built from 0.45-10 μm protist assemblages sampled over 13 months in a time series station in an arctic fjord in Svalbard. Community gene expression was correlated with seasonality, with light as the main driving factor. Transcript diversity and evenness were higher during polar night compared to polar day. Light-dependent functions had higher relative expression during polar day, except phototransduction. 64% of the most expressed genes could not be functionally annotated, yet up to 78% were identified in arctic samples from Tara Oceans, suggesting that arctic marine assemblages are distinct from those from other oceans. Our study increases understanding of the links between extreme seasonality and biological processes in pico- and nanoplanktonic protists. Our results set the ground for future monitoring studies investigating the seasonal impact of climate change on the communities of microbial eukaryotes in the High Arctic.

scholarly journals Relationship of cyanobacterial and algal assemblages with vegetation in the high Arctic tundra (West Spitsbergen, Svalbard Archipelago)

2015 ◽  
Vol 36 (3) ◽  
pp. 239-260 ◽  
Author(s):  
Dorota Richter ◽  
Mirosława Pietryka ◽  
Jan Matuła
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
High Arctic ◽  
Research Area ◽  
The Arctic ◽  
Svalbard Archipelago ◽  
The North ◽  
Algal Assemblages ◽  
West Spitsbergen ◽  
Relationship Of

AbstractThe paper presents the results of a study of cyanobacteria and green algae assemblages occurring in various tundra types determined on the basis of mosses and vascular plants and habitat conditions. The research was carried out during summer in the years 2009-2013 on the north sea-coast of Hornsund fjord (West Spitsbergen, Svalbard Archipelago). 58 sites were studied in various tundra types differing in composition of vascular plants, mosses and in trophy and humidity. 141 cyanobacteria and green algae were noted in the research area in total. Cyanobacteria and green algae flora is a significant element of many tundra types and sometimes even dominate there. Despite its importance, it has not been hitherto taken into account in the description and classification of tundra. The aim of the present study was to demonstrate the legitimacy of using phycoflora in supplementing the descriptions of hitherto described tundra and distinguishing new tundra types. Numeric hierarchical-accumulative classification (MVSP 3.1 software) methods were used to analyze the cyanobacterial and algal assemblages and their co-relations with particular tundra types. The analysis determined dominant and distinctive species in the communities in concordance with ecologically diverse types of tundra. The results show the importance of these organisms in the composition of the vegetation of tundra types and their role in the ecosystems of this part of the Arctic.

Summer phytoplankton of the northern Barents Sea (75–80º N)

2019 ◽  
pp. 8-19
Author(s):  
Larisa A. Pautova ◽  
Vladimir A. Silkin ◽  
Marina D. Kravchishina ◽  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Weighted Average ◽  
Arctic Basin ◽  
High Arctic ◽  
Alexandrium Tamarense ◽  
Warm Water ◽  
The Arctic ◽  
Absolute Maximum ◽  
Deep Trench ◽  
Maximum Biomass

The structure of the summer planktonic communities of the Northern part of the Barents sea in the first half of August 2017 were studied. In the sea-ice melting area, the average phytoplankton biomass producing upper 50-meter layer of water reached values levels of eutrophic waters (up to 2.1 g/m3). Phytoplankton was presented by diatoms of the genera Thalassiosira and Eucampia. Maximum biomass recorded at depths of 22–52 m, the absolute maximum biomass community (5,0 g/m3) marked on the horizon of 45 m (station 5558), located at the outlet of the deep trench Franz Victoria near the West coast of the archipelago Franz Josef Land. In ice-free waters, phytoplankton abundance was low, and the weighted average biomass (8.0 mg/m3 – 123.1 mg/m3) corresponded to oligotrophic waters and lower mesotrophic waters. In the upper layers of the water population abundance was dominated by small flagellates and picoplankton from, biomass – Arctic dinoflagellates (Gymnodinium spp.) and cold Atlantic complexes (Gyrodinium lachryma, Alexandrium tamarense, Dinophysis norvegica). The proportion of Atlantic species in phytoplankton reached 75%. The representatives of warm-water Atlantic complex (Emiliania huxleyi, Rhizosolenia hebetata f. semispina, Ceratium horridum) were recorded up to 80º N, as indicators of the penetration of warm Atlantic waters into the Arctic basin. The presence of oceanic Atlantic species as warm-water and cold systems in the high Arctic indicates the strengthening of processes of “atlantificacion” in the region.

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