Taxon-specific epibenthic foraminiferal δ18O in the Arctic Ocean: Relationship to water masses, deep circulation, and brine release

2014 ◽  
Vol 113 ◽  
pp. 34-43 ◽  
Author(s):  
Andreas Mackensen ◽  
Seung-Il Nam
2017 ◽  
Vol 51 (14) ◽  
pp. 7913-7919 ◽  
Author(s):  
Daniel Carrizo ◽  
Anna Sobek ◽  
Joan A. Salvadó ◽  
Örjan Gustafsson

2013 ◽  
Vol 10 (6) ◽  
pp. 4273-4286 ◽  
Author(s):  
A. Monier ◽  
R. Terrado ◽  
M. Thaler ◽  
A. Comeau ◽  
E. Medrinal ◽  
...  

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.


2017 ◽  
Author(s):  
Kristian Kjellerup Kjeldsen ◽  
Wilhelm Weinrebe ◽  
Jørgen Bendtsen ◽  
Anders Anker Bjørk ◽  
Kurt Henrik Kjær

Abstract. We present bathymetry and hydrological observations collected in the summer of 2014 from two fjord systems in Southeast Greenland, using SS Activ with a multibeam system temporally installed over the side of the ship. Our results provide a detailed bathymetric map of the fjord complex around Skjoldungen Island and the outer part of Timmiarmiut Fjord and show far greater depths compared to the International Bathymetric Chart of the Arctic Ocean. The hydrography collected show different properties in the fjords with the bottom water masses below 240 m in Timmiarmiut Fjord being 1–2 °C warmer than in the two fjords around Skjoldungen Island, but data also illustrate the influence of sills on the exchange of deeper water masses within fjords. Moreover, evidence of subglacial discharge in Timmiarmiut Fjord, consistent with satellite observations of ice mélange set into motion, adds to our increasing understanding of the distribution of subglacial meltwater. Data is available through the PANGAEA website https://doi.pangaea.de/10.1594/PANGAEA.860627.


2008 ◽  
Vol 78 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Marika Marnela ◽  
Bert Rudels ◽  
K. Anders Olsson ◽  
Leif G. Anderson ◽  
Emil Jeansson ◽  
...  

2013 ◽  
Vol 10 (2) ◽  
pp. 3397-3430 ◽  
Author(s):  
A. Monier ◽  
R. Terrado ◽  
M. Thaler ◽  
A. M. Comeau ◽  
E. Medrinal ◽  
...  

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.


2013 ◽  
Vol 69 (2) ◽  
pp. 101-112 ◽  
Author(s):  
C Amano-Sato ◽  
S Akiyama ◽  
M Uchida ◽  
K Shimada ◽  
M Utsumi

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