Shifts in the dominance between diatoms and cryptophytes during three late summers in the Bransfield Strait (Antarctic Peninsula)

Polar Biology ◽  
2013 ◽  
Vol 36 (4) ◽  
pp. 537-547 ◽  
Author(s):  
Carlos Rafael Borges Mendes ◽  
Virginia Maria Tavano ◽  
Miguel Costa Leal ◽  
Márcio Silva de Souza ◽  
Vanda Brotas ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Bransfield Strait

Chapter 3.2b Bransfield Strait and James Ross Island: petrology

2021 ◽  
pp. M55-2018-37 ◽  
Author(s):  
Karsten M. Haase ◽  
Christoph Beier
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Island ◽  
The South ◽  
Bransfield Strait ◽  
Geodynamic Processes ◽  
James Ross Island ◽  
South Shetland Trench ◽  
Low Degrees ◽  
Back Arc ◽  
The Antarctic

AbstractYoung volcanic centres of the Bransfield Strait and James Ross Island occur along back-arc extensional structures parallel to the South Shetland island arc. Back-arc extension was caused by slab rollback at the South Shetland Trench during the past 4 myr. The variability of lava compositions along the Bransfield Strait results from varying degrees of mantle depletion and input of a slab component. The mantle underneath the Bransfield Strait is heterogeneous on a scale of approximately tens of kilometres with portions in the mantle wedge not affected by slab fluids. Lavas from James Ross Island east of the Antarctic Peninsula differ in composition from those of the Bransfield Strait in that they are alkaline without evidence for a component from a subducted slab. Alkaline lavas from the volcanic centres east of the Antarctic Peninsula imply variably low degrees of partial melting in the presence of residual garnet, suggesting variable thinning of the lithosphere by extension. Magmas in the Bransfield Strait form by relatively high degrees of melting in the shallow mantle, whereas the magmas some 150 km further east form by low degrees of melting deeper in the mantle, reflecting the diversity of mantle geodynamic processes related to subduction along the South Shetland Trench.

Thermogenic hydrocarbons in surface sediments of the Bransfield Strait, Antarctic Peninsula

Nature ◽  
1985 ◽  
Vol 314 (6006) ◽  
pp. 87-90 ◽  
Author(s):  
M. J. Whiticar ◽  
E. Suess ◽  
H. Wehner
Keyword(s):  
Antarctic Peninsula ◽  
Surface Sediments ◽  
Bransfield Strait

scholarly journals Encounter rates and abundance of humpback whales (Megaptera novaeangliae) in Gerlache and Bransfield Straits, Antarctic Peninsula

2020 ◽  
pp. 107-111
Author(s):  
Eduardo R. Secchi ◽  
Luciano Dalla Rosa ◽  
Paul G. Kinas ◽  
Raquel F. Nicolette ◽  
Anne N. M. Rufino ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Distance Sampling ◽  
Austral Summer ◽  
Humpback Whales ◽  
Encounter Rate ◽  
Encounter Rates ◽  
Abundance Estimate ◽  
Bransfield Strait ◽  
Distance Data ◽  
The Difference

During the austral summer of 2006, the Projeto Baleias/Brazilian Antarctic Program (PROANTAR) conducted ship surveys for estimating whale encounter rates and abundance in Gerlache and Bransfield Straits, westward of the Antarctic Peninsula (edge between IWC Areas I and II). The encounter rate was higher in the Bransfield Strait (0.32 groups n. mile–1; 95% CI: 0.26–0.39) than in the Gerlache Strait (0.24 groups n. mile–1; 95% CI: 0.13–0.44), though the difference was not statistically evident. An abundance estimate using conventional distance sampling methods was computed only for the Bransfield Strait. The perpendicular distance data was best fitted by the half-normal model without adjustments. Derived abundance for the surveyed area was 865 humpback whales (95% CI = 656–1,141; CV = 14.13). This area represents only a small fraction of the Stock G feeding ground.

scholarly journals Natural iron enrichment around the Antarctic Peninsula in the Southern Ocean

2009 ◽  
Vol 6 (4) ◽  
pp. 7481-7515 ◽  
Author(s):  
M. V. Ardelan ◽  
O. Holm-Hansen ◽  
C. D. Hewes ◽  
C. S. Reiss ◽  
N. S. Silva ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Weddell Sea ◽  
South Shetland Islands ◽  
The South ◽  
Total Acid ◽  
Shetland Islands ◽  
Iron Enrichment ◽  
Bransfield Strait ◽  
Natural Iron ◽  
The Antarctic

Abstract. As part of the US-AMLR program that occupied 99 hydrographic stations in the South Shetland Islands-Antarctic Peninsula region in January–February of 2006, concentrations of dissolved iron (DFe) and total acid-leachable iron (TaLFe) were measured in the upper 150 m at 16 stations (both coastal and pelagic waters). The concentrations in the upper mixed layer (UML) of DFe and TaLFe were relatively high in Weddell Sea Shelf Waters (~0.6 nM and 15 nM, respectively) and lowest in Drake Passage waters (~0.2 nM and 0.9 nM, respectively). In the Bransfield Strait, representing a mixture of waters from the Weddell Sea and the Antarctic Circumpolar Current (ACC), concentrations of DFe were ~0.4 nM and of TaLFe ~1.7 nM. The highest concentrations of DFe and TaLFe in the UML were found at shallow coastal stations close to Livingston Island (~1.6 nM and 100 nM, respectively). The ratio of TaLFe:DFe varied with the distance to land: ~45 at the shallow coastal stations, ~15 in the high-salinity waters of Bransfield Strait, and ~4 in ACC waters. Concentrations of DFe increased slightly with depth in the water column, while that of TaLFe did not show any consistent trend with depth. Our data are consistent with the hypothesis that the relatively high rates of primary production known from the central regions of the Scotia Sea are partially sustained by natural iron enrichment resulting from a northeasterly flow of iron-rich coastal waters originating in the South Shetland Islands-Antarctic Peninsula region.

scholarly journals Spatial Structure and Intra-Annual Variability of Weddell Sea Front based on the Data of NOAA OISST Reanalysis

2020 ◽  
Author(s):  
Yu. V. Artamonov ◽  
E. A. Skripaleva ◽  
N. V. Nikolsky ◽  
◽  
◽  
...  
Keyword(s):  
Spatial Structure ◽  
Antarctic Peninsula ◽  
Time Lag ◽  
Water Area ◽  
Weddell Sea ◽  
The South ◽  
Orkney Islands ◽  
Bransfield Strait ◽  
South Orkney Islands ◽  
The Antarctic

Based on the NOAA OISST reanalysis data, the spatial structure of the Weddell Sea Front in the climatic field of the sea surface temperature was analyzed and the seasonal variability of front’s characteristics was estimated. The spatial position of the frontal zone in the Weddell Sea was analyzed using distributions of the total horizontal temperature gradient. The characteristics of the front (the position of the gradients' extrema corresponding to the front, their magnitude and temperature on the front axis) were determined for each month on the profiles of meridional and zonal temperature gradients along meridians and parallels with a discreteness of 2.5° of longitude and 0.25° of latitude. It is shown that the interaction of Weddell Sea cold waters, which are transported by currents northward along the Antarctic Peninsula coasts, with the warmer waters of the eastern shelf of the Antarctic Peninsula and the Bransfield Strait surface water causes formation of two branches of the Weddell Sea Front. These branches round from a vast shelf at the Antarctic Peninsula tip and the Joinville archipelago the south and north and are traced further east along the boundaries of the bottom rise located approximately between 62.5S and 64.5S. To the south of the South Orkney Islands shelf, the two branches merge into one front, which follows to the east along the depth dump of the relative shallow between the South Orkney and South Sandwich Islands. In the seasonal cycle of the Weddell Sea Front intensity, a time lag was revealed of the front intensification period in the direction from west to east. In Bransfield Strait the front is most intense in February, between the Antarctic Peninsula tip and the South Orkney Islands – in March, east of the South Orkney Islands – in April. The branch of the Weddell Sea Front off the northeastern of the Antarctic Peninsula coasts intensifies in November – January, in the western part of the water area east of the James Ross and Snow Hill Islands – in January – February.

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