scholarly journals Microbial genomes retrieved from High Arctic lake sediments encode for adaptation to cold and oligotrophic environments

2019 ◽  
Author(s):  
Matti O. Ruuskanen ◽  
Graham Colby ◽  
Kyra A. St.Pierre ◽  
Vincent L. St.Louis ◽  
Stéphane Aris-Brosou ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Environmental Changes ◽  
High Arctic ◽  
Trophic Levels ◽  
The Arctic ◽  
Metagenomic Sequencing ◽  
Microbial Genomes ◽  
High Prevalence ◽  
Low Prevalence ◽  
Candidate Phyla Radiation

AbstractThe Arctic is currently warming at an unprecedented rate, which may affect environmental constraints on the freshwater microbial communities found there. Yet, our knowledge of the community structure and functional potential of High Arctic freshwater microbes remains poor, even though they play key roles in nutrient cycling and other ecosystem services. Here, using high-throughput metagenomic sequencing and genome assembly, we show that sediment microbial communities in the High Arctic’s largest lake by volume, Lake Hazen, are phylogenetically diverse, ranging from Proteobacteria, Verrucomicrobia, Planctomycetes, to members of the newly discovered Candidate Phyla Radiation (CPR) groups. These genomes displayed a high prevalence of pathways involved in lipid chemistry, and a low prevalence of nutrient uptake pathways, which might represent adaptations to the specific, cold (~3.5°C) and extremely oligotrophic conditions in Lake Hazen. Despite these potential adaptations, it is unclear how ongoing environmental changes will affect microbial communities, the makeup of their genomic idiosyncrasies, as well as the possible implications at higher trophic levels.

Comparative metagenome analysis of an Alaskan glacier

2014 ◽  
Vol 12 (02) ◽  
pp. 1441003 ◽  
Author(s):  
Sulbha Choudhari ◽  
Ruchi Lohia ◽  
Andrey Grigoriev
Keyword(s):  
Principal Component ◽  
Arctic Region ◽  
High Arctic ◽  
The Arctic ◽  
Metagenomic Sequencing ◽  
Alpine Glacier ◽  
Metagenome Analysis ◽  
Subglacial Lake ◽  
Distinct Sequence ◽  
Taxonomic Groups

The temperature in the Arctic region has been increasing in the recent past accompanied by melting of its glaciers. We took a snapshot of the current microbial inhabitation of an Alaskan glacier (which can be considered as one of the simplest possible ecosystems) by using metagenomic sequencing of 16S rRNA recovered from ice/snow samples. Somewhat contrary to our expectations and earlier estimates, a rich and diverse microbial population of more than 2,500 species was revealed including several species of Archaea that has been identified for the first time in the glaciers of the Northern hemisphere. The most prominent bacterial groups found were Proteobacteria, Bacteroidetes, and Firmicutes. Firmicutes were not reported in large numbers in a previously studied Alpine glacier but were dominant in an Antarctic subglacial lake. Representatives of Cyanobacteria, Actinobacteria and Planctomycetes were among the most numerous, likely reflecting the dependence of the ecosystem on the energy obtained through photosynthesis and close links with the microbial community of the soil. Principal component analysis (PCA) of nucleotide word frequency revealed distinct sequence clusters for different taxonomic groups in the Alaskan glacier community and separate clusters for the glacial communities from other regions of the world. Comparative analysis of the community composition and bacterial diversity present in the Byron glacier in Alaska with other environments showed larger overlap with an Arctic soil than with a high Arctic lake, indicating patterns of community exchange and suggesting that these bacteria may play an important role in soil development during glacial retreat.

scholarly journals Climate change negatively impacts dominant microbes in the sediments of a High Arctic lake

2019 ◽  
Author(s):  
Graham A. Colby ◽  
Matti O. Ruuskanen ◽  
Kyra A. St. Pierre ◽  
Vincent L. St. Louis ◽  
Alexandre J. Poulain ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Environmental Changes ◽  
High Arctic ◽  
The Arctic ◽  
Large Lake ◽  
Spatial Gradients ◽  
Functional Potential ◽  
High Runoff ◽  
Sediment Microbes

AbstractTemperatures in the Arctic are expected to increase dramatically over the next century, yet little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large lake at these latitudes to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude / high altitudes ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.

scholarly journals 40 years High Arctic climatological dataset of the Polish Polar Station Hornsund (SW Spitsbergen, Svalbard)

2019 ◽  
Author(s):  
Tomasz Wawrzyniak ◽  
Marzena Osuch
Keyword(s):  
Environmental Changes ◽  
High Arctic ◽  
The Arctic ◽  
Data Series ◽  
Annual Data ◽  
Climate Data ◽  
Atlantic Sector ◽  
Svalbard Archipelago

Abstract. The article presents the climatological dataset from the Polish Polar Station Hornsund located in the SW part of Spitsbergen - the biggest island of the Svalbard Archipelago. Due to a general lack of long-term in situ measurements and observations, the high Arctic remains one of the largest climate‐data deficient regions on the Earth, so described series is of unique value. To draw conclusions on the climatic changes in the Arctic, it is necessary to analyse the long-term series of continuous, systematic, in situ observations from different locations and comparing the corresponding data, rather than rely on the climatic simulations only. In recent decades, rapid environmental changes occurring in the Atlantic sector of the Arctic are reflected in the data series collected by the operational monitoring conducted at the Hornsund Station. We demonstrate the results of the 40 years-long series of observations. Climatological mean values or totals are given, and we also examined the variability of meteorological variables at monthly and annual scale using the modified Mann-Kendall test for trend and Sen’s method. The relevant daily, monthly, and annual data are provided on the PANGAEA repository (https://doi.org/10.1594/PANGAEA.909042, Wawrzyniak and Osuch, 2019).

scholarly journals Daily transcriptomes of the copepod Calanus finmarchicus during the summer solstice at high Arctic latitudes

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Laura Payton ◽  
Céline Noirot ◽  
Claire Hoede ◽  
Lukas Hüppe ◽  
Kim Last ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sea Ice ◽  
Marine Ecosystem ◽  
High Arctic ◽  
Trophic Levels ◽  
Calanus Finmarchicus ◽  
The Arctic ◽  
Summer Solstice ◽  
Important Species ◽  
Ice Coverage

AbstractThe zooplankter Calanus finmarchicus is a member of the so-called “Calanus Complex”, a group of copepods that constitutes a key element of the Arctic polar marine ecosystem, providing a crucial link between primary production and higher trophic levels. Climate change induces the shift of C. finmarchicus to higher latitudes with currently unknown impacts on its endogenous timing. Here we generated a daily transcriptome of C. finmarchicus at two high Arctic stations, during the more extreme time of Midnight Sun, the summer solstice. While the southern station (74.5 °N) was sea ice-free, the northern one (82.5 °N) was sea ice-covered. The mRNAs of the 42 samples have been sequenced with an average of 126 ± 5 million reads (mean ± SE) per sample, and aligned to the reference transcriptome. We detail the quality assessment of the datasets and the complete annotation procedure, providing the possibility to investigate daily gene expression of this ecologically important species at high Arctic latitudes, and to compare gene expression according to latitude and sea ice-coverage.

Freshwater microbial community diversity in a rapidly changing High Arctic watershed

2019 ◽  
Vol 95 (11) ◽  
Author(s):  
Maria Antonia Cavaco ◽  
Vincent Lawrence St. Louis ◽  
Katja Engel ◽  
Kyra Alexandra St. Pierre ◽  
Sherry Lin Schiff ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Microbial Community ◽  
Microbial Communities ◽  
Active Layer ◽  
Hydrological Cycle ◽  
High Arctic ◽  
The Arctic ◽  
Future Climate Change ◽  
Freshwater Ecosystem ◽  
Rrna Gene

ABSTRACT Current models predict increases in High Arctic temperatures and precipitation that will have profound impacts on the Arctic hydrological cycle, including enhanced glacial melt and thawing of active layer soils. However, it remains uncertain how these changes will impact the structure of downstream resident freshwater microbial communities and ensuing microbially driven freshwater ecosystem services. Using the Lake Hazen watershed (Nunavut, Canada; 82°N, 71°W) as a sentinel system, we related microbial community composition (16S rRNA gene sequencing) to physicochemical parameters (e.g. dissolved oxygen and nutrients) over an annual hydrological cycle in three freshwater compartments within the watershed: (i) glacial rivers; (ii) active layer thaw-fed streams and waterbodies and (iii) Lake Hazen, into which (i) and (ii) drain. Microbial communities throughout these freshwater compartments were strongly interconnected, hydrologically, and often correlated with the presence of melt-sourced chemicals (e.g. dissolved inorganic carbon) as the melt season progressed. Within Lake Hazen itself, water column microbial communities were generally stable over spring and summer, despite fluctuating lake physicochemistry, indicating that these communities and the potential ecosystem services they provide therein may be resilient to environmental change. This work helps to establish a baseline understanding of how microbial communities and the ecosystem services they provide in Arctic watersheds might respond to future climate change.

scholarly journals Spatial Patterns of Macromolecular Composition of Phytoplankton in the Arctic Ocean

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2495
Author(s):  
Keyseok Choe ◽  
Misun Yun ◽  
Sanghoon Park ◽  
Eunjin Yang ◽  
Jinyoung Jung ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Environmental Changes ◽  
Trophic Levels ◽  
Canada Basin ◽  
The Arctic ◽  
Food Material ◽  
The Arctic Ocean ◽  
Biochemical Compositions ◽  
Chukchi Shelf ◽  
Macromolecular Composition

The macromolecular concentrations and compositions of phytoplankton are crucial for the growth or nutritional structure of higher trophic levels through the food web in the ecosystem. To understand variations in macromolecular contents of phytoplankton, we investigated the macromolecular components of phytoplankton and analyzed their spatial pattern on the Chukchi Shelf and the Canada Basin. The carbohydrate (CHO) concentrations on the Chukchi Shelf and the Canada Basin were 50.4–480.8 μg L−1 and 35.2–90.1 μg L−1, whereas the lipids (LIP) concentrations were 23.7–330.5 μg L−1 and 11.7–65.6 μg L−1, respectively. The protein (PRT) concentrations were 25.3–258.5 μg L−1 on the Chukchi Shelf and 2.4–35.1 μg L−1 in the Canada Basin. CHO were the predominant macromolecules, accounting for 42.6% on the Chukchi Shelf and 60.5% in the Canada Basin. LIP and PRT contributed to 29.7% and 27.7% of total macromolecular composition on the Chukchi Shelf and 30.8% and 8.7% in the Canada Basin, respectively. Low PRT concentration and composition in the Canada Basin might be a result from the severe nutrient-deficient conditions during phytoplankton growth. The calculated food material concentrations were 307.8 and 98.9 μg L−1, and the average calorie contents of phytoplankton were 1.9 and 0.6 kcal m−3 for the Chukchi Shelf and the Canada Basin, respectively, which indicates the phytoplankton on the Chukchi Shelf could provide the large quantity of food material and high calories to the higher trophic levels. Overall, our results highlight that the biochemical compositions of phytoplankton are considerably different in the regions of the Arctic Ocean. More studies on the changes in the biochemical compositions of phytoplankton are still required under future environmental changes.

scholarly journals Methane-derived carbon flows into host–virus networks at different trophic levels in soil

2021 ◽  
Vol 118 (32) ◽  
pp. e2105124118
Author(s):  
Sungeun Lee ◽  
Ella T. Sieradzki ◽  
Alexa M. Nicolas ◽  
Robin L. Walker ◽  
Mary K. Firestone ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Stable Isotope Probing ◽  
Trophic Levels ◽  
Methylotrophic Bacteria ◽  
Metagenomic Sequencing ◽  
Atmospheric Methane ◽  
Diverse Range ◽  
Soil Microbial ◽  
Predatory Bacteria

The concentration of atmospheric methane (CH4) continues to increase with microbial communities controlling soil–atmosphere fluxes. While there is substantial knowledge of the diversity and function of prokaryotes regulating CH4 production and consumption, their active interactions with viruses in soil have not been identified. Metagenomic sequencing of soil microbial communities enables identification of linkages between viruses and hosts. However, this does not determine if these represent current or historical interactions nor whether a virus or host are active. In this study, we identified active interactions between individual host and virus populations in situ by following the transfer of assimilated carbon. Using DNA stable-isotope probing combined with metagenomic analyses, we characterized CH4-fueled microbial networks in acidic and neutral pH soils, specifically primary and secondary utilizers, together with the recent transfer of CH4-derived carbon to viruses. A total of 63% of viral contigs from replicated soil incubations contained homologs of genes present in known methylotrophic bacteria. Genomic sequences of 13C-enriched viruses were represented in over one-third of spacers in CRISPR arrays of multiple closely related Methylocystis populations and revealed differences in their history of viral interaction. Viruses infecting nonmethanotrophic methylotrophs and heterotrophic predatory bacteria were also identified through the analysis of shared homologous genes, demonstrating that carbon is transferred to a diverse range of viruses associated with CH4-fueled microbial food networks.

scholarly journals Sea ice phenology and primary productivity pulses shape breeding success in Arctic seabirds

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Francisco Ramírez ◽  
Arnaud Tarroux ◽  
Johanna Hovinen ◽  
Joan Navarro ◽  
Isabel Afán ◽  
...  
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Regional Scale ◽  
High Arctic ◽  
Trophic Levels ◽  
The Arctic ◽  
Ice Melt ◽  
Circumpolar Arctic ◽  
Suitable Framework ◽  
Ice Phenology

Abstract Spring sea ice phenology regulates the timing of the two consecutive pulses of marine autotrophs that form the base of the Arctic marine food webs. This timing has been suggested to be the single most essential driver of secondary production and the efficiency with which biomass and energy are transferred to higher trophic levels. We investigated the chronological sequence of productivity pulses and its potential cascading impacts on the reproductive performance of the High Arctic seabird community from Svalbard, Norway. We provide evidence that interannual changes in the seasonal patterns of marine productivity may impact the breeding performance of little auks and Brünnich’s guillemots. These results may be of particular interest given that current global warming trends in the Barents Sea region predict one of the highest rates of sea ice loss within the circumpolar Arctic. However, local- to regional-scale heterogeneity in sea ice melting phenology may add uncertainty to predictions of climate-driven environmental impacts on seabirds. Indeed, our fine-scale analysis reveals that the inshore Brünnich’s guillemots are facing a slower advancement in the timing of ice melt compared to the offshore-foraging little auks. We provide a suitable framework for analyzing the effects of climate-driven sea ice disappearance on seabird fitness.

scholarly journals Terrestrial Inputs Shape Coastal Bacterial and Archaeal Communities in a High Arctic Fjord (Isfjorden, Svalbard)

2021 ◽  
Vol 12 ◽  
Author(s):  
Lisa-Marie Delpech ◽  
Tobias R. Vonnahme ◽  
Maeve McGovern ◽  
Rolf Gradinger ◽  
Kim Præbel ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Coastal Waters ◽  
Environmental Gradients ◽  
Late Summer ◽  
High Arctic ◽  
Atlantic Water ◽  
The Arctic ◽  
Rrna Gene ◽  
Terrestrial Runoff ◽  
Terrestrial Inputs

The Arctic is experiencing dramatic changes including increases in precipitation, glacial melt, and permafrost thaw, resulting in increasing freshwater runoff to coastal waters. During the melt season, terrestrial runoff delivers carbon- and nutrient-rich freshwater to Arctic coastal waters, with unknown consequences for the microbial communities that play a key role in determining the cycling and fate of terrestrial matter at the land-ocean interface. To determine the impacts of runoff on coastal microbial (bacteria and archaea) communities, we investigated changes in pelagic microbial community structure between the early (June) and late (August) melt season in 2018 in the Isfjorden system (Svalbard). Amplicon sequences of the 16S rRNA gene were generated from water column, river and sediment samples collected in Isfjorden along fjord transects from shallow river estuaries and glacier fronts to the outer fjord. Community shifts were investigated in relation to environmental gradients, and compared to river and marine sediment microbial communities. We identified strong temporal and spatial reorganizations in the structure and composition of microbial communities during the summer months in relation to environmental conditions. Microbial diversity patterns highlighted a reorganization from rich communities in June toward more even and less rich communities in August. In June, waters enriched in dissolved organic carbon (DOC) provided a niche for copiotrophic taxa including Sulfitobacter and Octadecabacter. In August, lower DOC concentrations and Atlantic water inflow coincided with a shift toward more cosmopolitan taxa usually associated with summer stratified periods (e.g., SAR11 Clade Ia), and prevalent oligotrophic marine clades (OM60, SAR92). Higher riverine inputs of dissolved inorganic nutrients and suspended particulate matter also contributed to spatial reorganizations of communities in August. Sentinel taxa of this late summer fjord environment included taxa from the class Verrucomicrobiae (Roseibacillus, Luteolibacter), potentially indicative of a higher fraction of particle-attached bacteria. This study highlights the ecological relevance of terrestrial runoff for Arctic coastal microbial communities and how its impacts on biogeochemical conditions may make these communities susceptible to climate change.

scholarly journals A 40-year High Arctic climatological dataset of the Polish Polar Station Hornsund (SW Spitsbergen, Svalbard)

2020 ◽  
Vol 12 (2) ◽  
pp. 805-815 ◽  
Author(s):  
Tomasz Wawrzyniak ◽  
Marzena Osuch
Keyword(s):  
Environmental Changes ◽  
High Arctic ◽  
The Arctic ◽  
Data Series ◽  
Annual Data ◽  
Climate Data ◽  
Atlantic Sector ◽  
Svalbard Archipelago

Abstract. The article presents the climatological dataset from the Polish Polar Station Hornsund located in the southwest part of Spitsbergen – the biggest island of the Svalbard archipelago. Due to a general lack of long-term in situ measurements and observations, the High Arctic remains one of the largest climate-data-deficient regions on the Earth. Therefore, the described time series of observations in this paper are of unique value. To draw conclusions on the climatic changes in the Arctic, it is necessary to analyse and compare the long-term series of continuous, in situ observations from different locations, rather than relying on the climatic simulations only. In recent decades, rapid environmental changes occurring in the Atlantic sector of the Arctic are reflected in the data series collected by the operational monitoring conducted at the Hornsund station. We demonstrate the results of the 40-year-long series of observations. Climatological mean values or totals are given, and we also examined the variability of meteorological variables at monthly and annual scale using the modified Mann–Kendall test for trend and Sen's method. The relevant daily, monthly, and annual data are provided on the PANGAEA repository (https://doi.org/10.1594/PANGAEA.909042, Wawrzyniak and Osuch, 2019).

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