scholarly journals Effects of Vertical Water Mass Segregation on Bacterial Community Structure in the Beaufort Sea

2019 ◽  
Vol 7 (10) ◽  
pp. 385
Author(s):  
Yunyun Fu ◽  
Richard B. Rivkin ◽  
Andrew S. Lang
Keyword(s):  
Bacterial Community ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Community Composition ◽  
Bacterial Communities ◽  
Water Mass ◽  
Beaufort Sea ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Mass Segregation

The Arctic Ocean is one of the least well-studied marine microbial ecosystems. Its low-temperature and low-salinity conditions are expected to result in distinct bacterial communities, in comparison to lower latitude oceans. However, this is an ocean currently in flux, with climate change exerting pronounced effects on sea-ice coverage and freshwater inputs. How such changes will affect this ecosystem are poorly constrained. In this study, we characterized the bacterial community compositions at different depths in both coastal, freshwater-influenced, and pelagic, sea-ice-covered locations in the Beaufort Sea in the western Canadian Arctic Ocean. The environmental factors controlling the bacterial community composition and diversity were investigated. Alphaproteobacteria dominated the bacterial communities in samples from all depths and stations. The Pelagibacterales and Rhodobacterales groups were the predominant taxonomic representatives within the Alphaproteobacteria. Bacterial communities in coastal and offshore samples differed significantly, and vertical water mass segregation was the controlling factor of community composition among the offshore samples, regardless of the taxonomic level considered. These data provide an important baseline view of the bacterial community in this ocean system that will be of value for future studies investigating possible changes in the Arctic Ocean in response to global change and/or anthropogenic disturbance.

Increasing Multiyear Sea Ice Loss in the Beaufort Sea: A New Export Pathway for the Diminishing Multiyear Ice Cover of the Arctic Ocean

2021 ◽  
Author(s):  
David Gareth Babb ◽  
Ryan J. Galley ◽  
Stephen E. L. Howell ◽  
Jack Christopher Landy ◽  
Julienne Christine Stroeve ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Beaufort Sea ◽  
Ice Cover ◽  
The Arctic ◽  
Export Pathway ◽  
The Arctic Ocean ◽  
Multiyear Ice

scholarly journals The effects of tides on the water mass mixing and sea ice in the Arctic Ocean

2015 ◽  
Vol 120 (10) ◽  
pp. 6669-6699 ◽  
Author(s):  
Maria V. Luneva ◽  
Yevgeny Aksenov ◽  
James D. Harle ◽  
Jason T. Holt
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Water Mass ◽  
The Arctic ◽  
The Arctic Ocean

Arctic summer sea-ice SAR signatures, melt-season characteristics, and melt-pond fractions

Polar Record ◽  
1997 ◽  
Vol 33 (185) ◽  
pp. 101-112 ◽  
Author(s):  
M. O. Jeffries ◽  
K. Schwartz ◽  
S. Li
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Late Summer ◽  
Beaufort Sea ◽  
Early Summer ◽  
The Arctic ◽  
Late Winter ◽  
Melt Pond ◽  
Melt Ponds ◽  
The Arctic Ocean

AbstractVariations in multiyear sea-ice backscatter from the synthetic aperture radar (SAR) aboard the ERS-1 satellite are interpreted in terms of melt-season characteristics (onset of melt in spring and of freeze-up in autumn, and the duration of the snow-decay period, the melt season, and the melt-pond season) from late winter to early autumn 1992 in two regions of the Arctic Ocean: the northeastern Beaufort Sea adjacent to the Queen Elizabeth Islands in the Canadian high Arctic and the western Beaufort Sea north of Alaska. In the northeastern Beaufort Sea, the onset of melt occurs later, and the periods of snow-cover decay and the occurrence of melt ponds are shorter than in the western Beaufort Sea. These melt-season characteristics of each area are consistent with previous observations that the northeastern Beaufort Sea has one of the most severe summer climates in the Arctic Ocean. A model, which assumes that the backscatter from multiyear floes is the sum of backscatter from bare ice and melt ponds, is used to derive the melt-pond fraction during the summer. The results show that melt-pond fractions decrease from an early-summer maximum of about 60% to a late-summer minimum around 10%. The magnitude of the melt-pond fractions and their decline during the summer is consistent with previous, more qualitative data. The SAR model, which gives melt-pond fractions with lower variability and less uncertainty than previous data, offers an improved approach to the reliable estimation of the areal extent of water on ice floes. Suggestions for further improvement of the model include accounting for the consequences of wind-speed variations, summer snowfall, and freeze/thaw cycles and their effects on melt-pond and ice-surface roughness.

scholarly journals Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

2013 ◽  
Vol 10 (6) ◽  
pp. 4273-4286 ◽  
Author(s):  
A. Monier ◽  
R. Terrado ◽  
M. Thaler ◽  
A. Comeau ◽  
E. Medrinal ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Water Column ◽  
Community Composition ◽  
Beaufort Sea ◽  
Water Masses ◽  
The Arctic ◽  
Heterotrophic Flagellates ◽  
Chlorophyll Maximum ◽  
Subsurface Chlorophyll Maximum ◽  
The Arctic Ocean

Abstract. The ubiquity of heterotrophic flagellates (HFL) in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8–20 μm cell diameter), mostly phagotrophic protists in the upper pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum layer, where light and nutrients are both available. This physically well-characterized system provided an opportunity to explore the community diversity of HFL from different water masses within the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada), targeting the surface, the subsurface chlorophyll maximum layer (SCM) and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1) to examine the possibility of niche differentiation within the stratified water column. Our results strongly suggested that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate-driven changes to the physical structure of the Arctic Ocean.

scholarly journals Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

2013 ◽  
Vol 10 (2) ◽  
pp. 3397-3430 ◽  
Author(s):  
A. Monier ◽  
R. Terrado ◽  
M. Thaler ◽  
A. M. Comeau ◽  
E. Medrinal ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Water Column ◽  
Community Composition ◽  
Beaufort Sea ◽  
Water Masses ◽  
Community Diversity ◽  
The Arctic ◽  
Heterotrophic Flagellates ◽  
Environmental Selection ◽  
The Arctic Ocean

Abstract. The ubiquity of heterotrophic flagellates (HFL) in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8–20 μm cell diameter), mostly phagotrophic protists in the pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum (SCM) layer. This physically well-characterized system provided an opportunity to explore the community diversity of HFL across a wide region, and down the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada), targeting the surface, the SCM and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1) to examine the possibility of niche differentiation within the stratified water column. Our results strongly implied that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate driven changes to the physical structure of the Arctic Ocean.

scholarly journals Use of organic exudates from two polar diatoms by bacterial isolates from the Arctic Ocean

2020 ◽  
Vol 378 (2181) ◽  
pp. 20190356 ◽  
Author(s):  
Lucas Tisserand ◽  
Laëtitia Dadaglio ◽  
Laurent Intertaglia ◽  
Philippe Catala ◽  
Christos Panagiotopoulos ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
Model Systems ◽  
The Arctic ◽  
Bacterial Strains ◽  
Biological Communities ◽  
Polar Diatoms

Global warming affects primary producers in the Arctic, with potential consequences for the bacterial community composition through the consumption of microalgae-derived dissolved organic matter (DOM). To determine the degree of specificity in the use of an exudate by bacterial taxa, we used simple microalgae–bacteria model systems. We isolated 92 bacterial strains from the sea ice bottom and the water column in spring–summer in the Baffin Bay (Arctic Ocean). The isolates were grouped into 42 species belonging to Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. Forty strains were tested for their capacity to grow on the exudate from two Arctic diatoms . Most of the strains tested (78%) were able to grow on the exudate from the pelagic diatom Chaetoceros neogracilis , and 33% were able to use the exudate from the sea ice diatom Fragilariopsis cylindrus . 17.5% of the strains were not able to grow with any exudate, while 27.5% of the strains were able to use both types of exudates. All strains belonging to Flavobacteriia ( n  = 10) were able to use the DOM provided by C. neogracilis , and this exudate sustained a growth capacity of up to 100 times higher than diluted Marine Broth medium, of two Pseudomonas sp. strains and one Sulfitobacter strain. The variable bioavailability of exudates to bacterial strains highlights the potential role of microalgae in shaping the bacterial community composition. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

Pliocene palaeoceanography of the Arctic Ocean and subarctic seas

2008 ◽  
Vol 367 (1886) ◽  
pp. 21-48 ◽  
Author(s):  
Jens Matthiessen ◽  
Jochen Knies ◽  
Christoph Vogt ◽  
Ruediger Stein
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Water Mass ◽  
Regional Scale ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Tectonic Activity ◽  
Major Influence ◽  
Overturning Circulation ◽  
The Arctic Ocean

The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local- to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4 Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage systems, and exerted a major influence on the formation of continental ice sheets, the distribution of river run-off, and the circulation and water mass characteristics in the Arctic Ocean. The effect of a water mass exchange restricted to the Bering and Fram Straits on the oceanography is unknown, but modelling experiments suggest that this must have influenced the Atlantic meridional overturning circulation. Cold conditions associated with perennial sea-ice cover might have prevailed in the central Arctic Ocean throughout the Pliocene, whereas colder periods alternated with warmer seasonally ice-free periods in the marginal areas. The most pronounced oceanographic change occurred in the Mid-Pliocene when the circulation through the Bering Strait reversed and low-salinity waters increasingly flowed from the North Pacific into the Arctic Ocean. The excess freshwater supply might have facilitated sea-ice formation and contributed to a decrease in the Atlantic overturning circulation.

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