scholarly journals Metagenomic characterization of the viral community of the South Scotia Ridge

2018 ◽  
Author(s):  
Qingwei Yang ◽  
Chen Gao ◽  
Yong Jiang ◽  
Min Wang ◽  
Xinhao Zhou ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Antarctic Peninsula ◽  
Phylogenetic Analyses ◽  
Marker Genes ◽  
Scotia Ridge ◽  
The Pacific ◽  
Viral Communities ◽  
The Pacific Ocean ◽  
The Antarctic ◽  
South Scotia Ridge

AbstractViruses are the most abundant biological entities in aquatic ecosystems and harbor an enormous genetic diversity. While their great influence on the marine ecosystems is widely acknowledged, current information about their diversity remains scarce. Aviral metagenomic analysis of two surfaces and one bottom water sample was conducted from sites on the South Scotia Ridge (SSR) near the Antarctic Peninsula, during the austral summer 2016. The taxonomic composition and diversity of the viral communities were investigated and a functional assessment of the sequences was determined. Phylotypic analysis showed that most viruses belonging to the order Caudovirales, in particular, the family Podoviridae (41.92-48.7%), which is similar to the viral communities from the Pacific Ocean. Functional analysis revealed a relatively high frequency of phage-associated and metabolism genes. Phylogenetic analyses of phage TerL and Capsid_NCLDV (nucleocytoplasmic large DNA viruses) marker genes indicated that many of the sequences associated with Caudovirales and NCLDV were novel and distinct from known complete phage genomes. High Phaeocystis globosa virus virophage (Pgvv) signatures were found in SSR area and complete and partial Pgvv-like were obtained which may have an influence on host-virus interactions in the area during summer. Our study expands the existing knowledge of viral communities and their diversities from the Antarctic region and provides basic data for further exploring polar microbiomes.ImportanceIn this study, we used high-throughput sequencing and bioinformatics analysis to analyze the viral community structure and biodiversity of SSR in the open sea near the Antarctic Peninsula. The results showed that the SSR viromes are novel, oceanic-related viromes and a high proportion of sequence reads was classified as unknown. Among known virus counterparts, members of the order Caudovirales were most abundant which is consistent with viromes from the Pacific Ocean. In addition, phylogenetic analyses based on the viral marker genes (TerL and MCP) illustrate the high diversity among Caudovirales and NCLDV. Combining deep sequencing and a random subsampling assembly approach, a new Pgvv-like group was also found in this region, which may a signification factor regulating virus-host interactions.

scholarly journals Metagenomic Characterization of the Viral Community of the South Scotia Ridge

2018 ◽  
Author(s):  
Qingwei Yang ◽  
Chen Gao ◽  
Jiang Yong ◽  
Ming Wang ◽  
Xinhao Zhou ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Great Influence ◽  
Austral Summer ◽  
Taxonomic Composition ◽  
Marker Genes ◽  
The South ◽  
Scotia Ridge ◽  
Viral Communities ◽  
The Antarctic ◽  
South Scotia Ridge

Viruses are the most abundant biological entities in aquatic ecosystems and harbor an enormous genetic diversity. While their great influence on the marine ecosystems is widely acknowledged, current information about their diversity remains scarce. A viral metagenomic analysis of three water samples was conducted from sites on the South Scotia Ridge (SSR) near the Antarctic Peninsula, during the austral summer 2016. The taxonomic composition and diversity of the viral communities were investigated and a functional assessment of the sequences was determined. Phylotypic analysis showed that most viruses belonging to the order Caudovirales, especially the family Podoviridae (41.92-48.7%), similar to the viromes from the Pacific Ocean. Functional analysis revealed a relatively high frequency of phage-associated and metabolism genes. Phylogenetic analyses of phage TerL and Capsid_NCLDV (nucleocytoplasmic large DNA viruses) marker genes indicated that many sequences associated with Caudovirales and NCLDV were novel and distinct from known phage genomes. High Phaeocystis globosa virus virophage (Pgvv) signatures were found in SSR area and complete and partial Pgvv-like were obtained which may have an influence on host-virus interactions. Our study expands the existing knowledge of viral communities and their diversities from the Antarctic region and provides basic data for further exploring polar microbiomes.

scholarly journals Metagenomic Characterization of the Viral Community of the South Scotia Ridge

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 95 ◽  
Author(s):  
Qingwei Yang ◽  
Chen Gao ◽  
Yong Jiang ◽  
Min Wang ◽  
Xinhao Zhou ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Austral Summer ◽  
Taxonomic Composition ◽  
Marker Genes ◽  
The South ◽  
Scotia Ridge ◽  
Viral Communities ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
The Antarctic ◽  
South Scotia Ridge

Viruses are the most abundant biological entities in aquatic ecosystems and harbor an enormous amount of genetic diversity. Whereas their influence on marine ecosystems is widely acknowledged, current information about their diversity remains limited. We conducted a viral metagenomic analysis of water samples collected during the austral summer of 2016 from the South Scotia Ridge (SSR), near the Antarctic Peninsula. The taxonomic composition and diversity of the viral communities were investigated, and a functional assessment of the sequences was performed. Phylotypic analysis showed that most viruses belonged to the order Caudovirales, especially the family Podoviridae (41.92–48.7%), which is similar to the situation in the Pacific Ocean. Functional analysis revealed a relatively high frequency of phage-associated and metabolism genes. Phylogenetic analyses of phage TerL and Capsid_NCLDV (nucleocytoplasmic large DNA viruses) marker genes indicated that many sequences associated with Caudovirales and NCLDV were novel and distinct from known phage genomes. High Phaeocystis globosa virus virophage (Pgvv) signatures were found and complete and partial Pgvv-like were obtained, which influence host–virus interactions. Our study expands existing knowledge of viral communities and their diversities from the Antarctic region and provides basic data for further exploring polar microbiomes.

scholarly journals Dominant role of vertical air flows in the unprecedented warming on the Antarctic Peninsula in February 2020

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Min Xu ◽  
Lejiang Yu ◽  
Kaixin Liang ◽  
Timo Vihma ◽  
Deniz Bozkurt ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Antarctic Peninsula ◽  
Dominant Role ◽  
Austral Summer ◽  
Surface Air Temperature ◽  
Near Surface ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Air Flows ◽  
The Antarctic

AbstractNear-surface air temperature at the Argentinian research base Esperanza on the northern tip of the Antarctic Peninsula reached 18.3 °C on 6 February 2020, which is the highest temperature ever recorded on the entire Antarctic continent. Here we use weather observations since 1973 together with the ERA5 reanalysis to investigate the circulation that shaped the 2020 event, and its context over the past decades. We find that, during the 2020 event, a high-pressure ridge over the 40°-100°W sector and a blocking high on the Drake Passage led to an anticyclonic circulation that brought warm and moist air from the Pacific Ocean to the Antarctic Peninsula. Vertical air flows in a foehn warming event dominated by sensible heat and radiation made the largest contribution to the abrupt warming. A further analysis with 196 extreme warm events in austral summer between 1973 and 2020 suggests that the mechanisms behind the 2020 event form one of the two most common clusters of the events, exhibiting that most of the extreme warm events at Esperanza station are linked to air masses originating over the Pacific Ocean.

scholarly journals Antarctic ice-shelf calving triggered by the Honshu (Japan) earthquake and tsunami, March 2011

2011 ◽  
Vol 57 (205) ◽  
pp. 785-788 ◽  
Author(s):  
Kelly M. Brunt ◽  
Emile A. Okal ◽  
Douglas R. MacAyeal
Keyword(s):  
Pacific Ocean ◽  
Northern Hemisphere ◽  
European Space Agency ◽  
Observational Evidence ◽  
Ice Shelf ◽  
Wave Impact ◽  
Space Agency ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Antarctic

AbstractWe use European Space Agency Envisat data to present the first observational evidence that a Northern Hemisphere tsunami triggered Antarctic ice-shelf calving more than 13 000 km away. The Honshu tsunami of 11 March 2011 traversed the Pacific Ocean in <18 hours where it impinged on the Sulzberger Ice Shelf, resulting in the calving of 125 km2 of ice from a shelf front that had previously been stable for >46 years. This event further illustrates the growing evidence of ocean-wave impact on Antarctic calving and emphasizes the teleconnection between the Antarctic ice sheet and events as far away as the Northern Hemisphere.

scholarly journals Shewanella loihica sp. nov., isolated from iron-rich microbial mats in the Pacific Ocean

2006 ◽  
Vol 56 (8) ◽  
pp. 1911-1916 ◽  
Author(s):  
Haichun Gao ◽  
Anna Obraztova ◽  
Nathan Stewart ◽  
Radu Popa ◽  
James K. Fredrickson ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Mats ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Major Fatty Acid ◽  
Rrna Gene ◽  
The Pacific ◽  
The Pacific Ocean

A novel marine bacterial strain, PV-4T, isolated from a microbial mat located at a hydrothermal vent of Loihi Seamount in the Pacific Ocean, has been characterized. This micro-organism is orangey in colour, Gram-negative, polarly flagellated, facultatively anaerobic and psychrotolerant (temperature range, 0–42 °C). No growth was observed with nitrate, nitrite, DMSO or thiosulfate as the electron acceptor and lactate as the electron donor. The major fatty acid detected in strain PV-4T was iso-C15 : 0. Strain PV-4T had ubiquinones consisting mainly of Q-7 and Q-8, and possessed menaquinone MK-7. The DNA G+C content of the strain was 53.8 mol% and the genome size was about 4.5 Mbp. Phylogenetic analyses based on 16S rRNA gene sequences placed PV-4T within the genus Shewanella. PV-4T exhibited 16S rRNA gene sequence similarity levels of 99.6 and 97.5 %, respectively, with respect to the type strains of Shewanella aquimarina and Shewanella marisflavi. DNA from strain PV-4T showed low mean levels of relatedness to the DNAs of S. aquimarina (50.5 %) and S. marisflavi (8.5 %). On the basis of phylogenetic and phenotypic characteristics, the bacterium was classified in the genus Shewanella within a distinct novel species, for which the name Shewanella loihica sp. nov. is proposed. The type strain is PV-4T (=ATCC BAA-1088T=DSM 17748T).

scholarly journals Surface Circulation at the Tip of the Antarctic Peninsula from Drifters

2009 ◽  
Vol 39 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Andrew F. Thompson ◽  
Karen J. Heywood ◽  
Sally E. Thorpe ◽  
Angelika H. H. Renner ◽  
Armando Trasviña
Keyword(s):  
Antarctic Peninsula ◽  
Weddell Sea ◽  
Ecosystem Dynamics ◽  
Mean Flow ◽  
The South ◽  
Scotia Ridge ◽  
Surface Circulation ◽  
Dominant Feature ◽  
The Antarctic ◽  
South Scotia Ridge

Abstract An array of 40 surface drifters, drogued at 15-m depth, was deployed in February 2007 to the east of the tip of the Antarctic Peninsula as part of the Antarctic Drifter Experiment: Links to Isobaths and Ecosystems (ADELIE) project. Data obtained from these drifters and from a select number of local historical drifters provide the most detailed observations to date of the surface circulation in the northwestern Weddell Sea. The Antarctic Slope Front (ASF), characterized by a ∼20 cm s−1 current following the 1000-m isobath, is the dominant feature east of the peninsula. The slope front bifurcates when it encounters the South Scotia Ridge with the drifters following one of three paths. Drifters (i) are carried westward into Bransfield Strait; (ii) follow the 1000-m isobath to the east along the southern edge of the South Scotia Ridge; or (iii) become entrained in a large-standing eddy over the South Scotia Ridge. Drifters are strongly steered by contours of f /h (Coriolis frequency/depth) as shown by calculations of the first two moments of displacement in both geographic coordinates and coordinates locally aligned with contours of f /h. An eddy-mean decomposition of the drifter velocities indicates that shear in the mean flow makes the dominant contribution to dispersion in the along-f /h direction, but eddy processes are more important in dispersing particles across contours of f /h. The results of the ADELIE study suggest that the circulation near the tip of the Antarctic Peninsula may influence ecosystem dynamics in the Southern Ocean through Antarctic krill transport and the export of nutrients.

Kelvin Waves around Antarctica

2014 ◽  
Vol 44 (11) ◽  
pp. 2909-2920 ◽  
Author(s):  
Kazuya Kusahara ◽  
Kay I. Ohshima
Keyword(s):  
Pacific Ocean ◽  
Southern Ocean ◽  
Sea Level ◽  
Statistical Significance ◽  
Phase Speed ◽  
Drake Passage ◽  
Kelvin Waves ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Antarctic

Abstract The Southern Ocean allows circumpolar structure and the Antarctic coastline plays a role as a waveguide for oceanic Kelvin waves. Under the cyclic conditions, the horizontal wavenumbers and frequencies for circumpolarly propagating waves are quantized, with horizontal wavenumbers 1, 2, and 3, corresponding to periods of about 32, 16, and 11 h, respectively. At these frequencies, westward-propagating signals are detected in sea level variation observed at Antarctic coastal stations. The occurrence frequency of westward-propagating signals far exceeds the statistical significance, and the phase speed of the observed signal agrees well with the theoretical phase speed of external Kelvin waves. Therefore, this study concludes that the observed, westward-propagating sea level variability is a signal of the external Kelvin waves of wavenumbers 1, 2, and 3 around Antarctica. A series of numerical model experiments confirms that Kelvin waves around Antarctica are driven by surface air pressure and that these waves are excited not only by local forcing over the Southern Ocean, but also by remote forcing over the Pacific Ocean. Sea level variations generated over the Pacific Ocean can travel to the western side of the South American coast and cross over Drake Passage to the Antarctic continent, constituting a part of the Kelvin waves around Antarctica.

scholarly journals First record of Stylostomum ellipse (Dalyell, 1853) (Platyhelminthes, Polycladida) from the Pacific Ocean

Check List ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 773-779
Author(s):  
Aoi Tsuyuki ◽  
Yuki Oya ◽  
Hiroshi Kajihara
Keyword(s):  
Pacific Ocean ◽  
Mediterranean Sea ◽  
First Record ◽  
Antarctic Region ◽  
The Pacific ◽  
The Pacific Ocean ◽  
28S Rdna Sequence ◽  
The Antarctic ◽  
First Time ◽  
Northern Japan

The polyclad flatworm Stylostomum ellipse (Dalyell, 1853) has hitherto been recorded from the Antarctic region, Mediterranean Sea, Patagonian region, Scandinavia, South Africa, and South Georgia Island. In this study, we report S. ellipse for the first time from the Pacific Ocean based on specimens collected in Hokkaido, northern Japan. Our specimens are morphologically identifiable as S. ellipse, but may represent a biologically different species from a population of the Mediterranean Sea. This is because, based on the previous genetic data of other cotylean species, the observed uncorrected p-distance 0.02160 between the two distinct populations in terms of a partial 972 bp region of the 28S rDNA sequence may be great enough to separate the species biologically.

scholarly journals Changes in climatic tendencies in the Antarctic Peninsula region

2017 ◽  
pp. 29-37
Author(s):  
Volodymyr Kravchenko ◽  
Oleksandr Evtushevsky
Keyword(s):  
Antarctic Peninsula ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Winter Temperature ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Ocean Sector ◽  
The Stability ◽  
The Antarctic

Estimations of couplings of winter temperature in the Antarctic Peninsula region with tropical temperature anomalies indicate long term changes in the intensity of tropical influences. These changes are associated with the stability of the meridional wavetrain of stationary planetary waves, along which tropical disturbances in the Pacific Ocean sector propagate, affecting the climate of the Antarctic Peninsula. The period of the most significant tropical effects is the 1980s and the 1990s, and, at that time, the most rapid winter warming at Faraday/Vernadsky station was observed. One of the components of the winter temperature change on the peninsula is a 16year periodicity with amplitude of about 1oС that also contributes to regional climate change.

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