Radiolarian flux in Antarctic waters (Drake Passage, Powell Basin, Bransfield Strait)

Polar Biology ◽  
1992 ◽  
Vol 12 (3-4) ◽  
Author(s):  
Andrea Abelmann
Keyword(s):  
Drake Passage ◽  
Bransfield Strait ◽  
Antarctic Waters

scholarly journals Geophysical models of Drake passage and Bransfield strait crustal structure

2008 ◽  
pp. 9-14
Author(s):  
S. P. Levashov ◽  
◽  
N. A. Yakymchuk ◽  
I. N. Korchagin ◽  
V. G. Bakhmutov ◽  
...  
Keyword(s):  
Crustal Structure ◽  
Drake Passage ◽  
Bransfield Strait

In situ evidence for a nutrient limitation of phytoplankton growth in pelagic Antarctic waters

1994 ◽  
Vol 6 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Osmund Holm-Hansen ◽  
Anthony F. Amos ◽  
Nelson Silva S. ◽  
Virginia Villafañe ◽  
E. Walter Helbling
Keyword(s):  
Nutrient Limitation ◽  
Surface Waters ◽  
Phytoplankton Biomass ◽  
Drake Passage ◽  
Nutrient Concentrations ◽  
Ancillary Data ◽  
Water Types ◽  
Antarctic Waters ◽  
Subsurface Maximum

Studies in a large (30000 km2) sampling grid around Elephant Island, Antarctica, during January–March of four successive years (1990–1993) have shown that one of the water types within the sampling area (Drake Passage water) shows low chlorophyll a in surface waters and a subsurface maximum between 50 and 80 m depth. Ancillary data (beam attenuation, in situ chl a fluorescence) support the view that the extracted chl a values actually do represent increased phytoplankton biomass at depth; other data (oxygen concentrations and upwelling radiance at 683 nm) suggest that the phytoplankton within this subsurface maximum layer are photosynthetically active and do not represent a senescent, sinking population of cells. Such deep chl a maxima were found only in Drake Passage waters; in the other four water types sampled, chl a concentrations were maximal in surface waters and decreased with depth. Phytoplankton biomass and activity in Drake Passage waters is suggestive of a nutrient limitation for phytolankton growth in surface waters. Nutrient concentrations of N, P, and Si were high throughout the euphotic zone at all stations, and hence it is unlikely that any macronutrient would be limiting. The data presented in this paper support the hypothesis of Martin and colleagues that availability of Fe may limit phytoplankton biomass in pelagic Antarctic waters, but not in coastal waters where Fe concentrations are relatively high. All other reports on the effects of Fe on Antarctic phytoplankton have utilized deck incubations from which it is difficult to extrapolate such evidence of nutrient limitation to in situ conditions. Our data represent the first in situ evidence linking Fe limitation to the paradox of high macronutrient concentrations and low phytoplankton biomass in Antarctic pelagic waters.

Quaternary colonization or Paleogene persistence?: historical biogeography of skates (Chondrichthyes: Rajidae) in the Antarctic ichthyofauna

Paleobiology ◽  
1994 ◽  
Vol 20 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Douglas J. Long
Keyword(s):  
Western Europe ◽  
Middle Eocene ◽  
Habitat Preferences ◽  
Drake Passage ◽  
The Arctic ◽  
Western Atlantic ◽  
Western Tethys ◽  
Antarctic Waters ◽  
La Meseta Formation ◽  
Dispersal Corridor

Seven endemic species of skates (Chondrichthyes: Rajidae) represent the only family of elasmobranchs currently known to live in Antarctic continental waters. Many previous authors believed skates colonized Antarctic waters from Patagonia during interglacial periods in the Quaternary. However, recent fossil material collected from the middle Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula, indicates that they may have persisted in Antarctic waters since the Paleogene. Additionally, oceanographic barriers present in the Neogene and Quaternary would have prevented dispersal from southern continents to Antarctica. A revised dispersal scenario, based on skate fossils, biology, paleogeography, and present centers of skate diversity, suggests that skates evolved in the western Tethys and North Boreal seas of western Europe in the Late Cretaceous and early Paleogene and emigrated into Antarctica during the early to middle Eocene via a dispersal corridor along the continental margins of the western Atlantic Ocean. Skates probably populated the Pacific Basin by passing from this dispersal corridor through the Arctic Ocean. Vicariant events, such as opening of the Drake Passage, the development of the Circum-Antarctic Current, and formation of deep and wide basins around Antarctica in the late Paleogene, created barriers that isolated some species of skates in Antarctica and prevented movement of other species of skates into Antarctica from northern areas. Skates are the only group of fishes known to have survived the Oligocene cooling of Antarctica that killed or extirpated the Paleogene ichthyofauna; they persisted by a combination of cold-tolerance, generalized diet, and unspecialized bathymetric and habitat preferences.

scholarly journals Is there an active hydrothermal flux from the Orca seamount in the Bransfield Strait, Antarctica?

2018 ◽  
Vol 45 (3) ◽  
pp. 344
Author(s):  
Cristian Rodrigo ◽  
Jenny M. Blamey ◽  
Oliver Huhn ◽  
Christine Provost
Keyword(s):  
Temperature Anomaly ◽  
Extreme Environments ◽  
Plate Boundary ◽  
Hydrothermal Activity ◽  
Thermophilic Microorganisms ◽  
Bransfield Strait ◽  
Antarctic Waters ◽  
Beam Transmission ◽  
Back Arc ◽  
Roll Back

The rifting zone of Bransfield Strait, Antarctica, is tectonically and geologically unique. It is a back-arc basin that was opened by extensional forces associated to roll-back subduction after cessation of spreading activity of the Phoenix Ridge, and the transtension of the westward ending of Scotia-Antarctica Plate boundary. The Bransfield Rift/Ridge is still active generating volcanism or magma rise to force hydrothermal activity. During the ANT-XXV/4 cruise onboard R/V “Polarstern”, standard CTD and beam transmission measurements were done to determine temperature anomaly and turbidity. Water sampling was performed to determine δ3He and to find thermophilic microorganisms to examine the Orca seamount hydrothermal activity. A temperature anomaly of ~0.08 °C, a pick of turbidity, and high value of δ3He (>10%) were found inside Orca seamount. Results are consistent with a hydrothermal flux coming from the seamount. The report of the first observation of thermophilic and hyperthermophilic microorganisms in cold deep Antarctic waters is part of this study. Inside Orca seamount these microorganisms were found at three different depth levels close to the bottom. We suggest that the fluid migration from the volcano resulted from recent magmatic activity and provided the required elemental nutrients for microbial growth. Besides some thermophiles were found outside the seamount in a small quantity close to the seafloor. These would probably be related to subsidiary structures of the Orca seamount, or were transported by currents from other active volcanic sites as Deception Island. The finding of these thermophilic and hyperthermophilic microorganisms raise questions about the dispersal and their resistance in these extreme environments.

Microbes in antarctic waters of the Drake Passage: Vertical patterns of substrate uptake, productivity and biomass in January 1980

Polar Biology ◽  
1983 ◽  
Vol 2 (3) ◽  
pp. 179-188 ◽  
Author(s):  
R. B. Hanson ◽  
H. K. Lowery ◽  
D. Shafer ◽  
R. Sorocco ◽  
D. H. Pope
Keyword(s):  
Drake Passage ◽  
Substrate Uptake ◽  
Antarctic Waters

Primary Organic Production in the Drake Passage and Bransfield Strait

2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sayed Z. El-Sayed ◽  
Enrique F. Mandelli ◽  
Yukio Sugimura
Keyword(s):  
Drake Passage ◽  
Organic Production ◽  
Bransfield Strait

scholarly journals The distribution, abundance and community structure of marine birds in southern Drake Passage and Bransfield Strait, Antarctica

1990 ◽  
Vol 10 (3) ◽  
pp. 243-257 ◽  
Author(s):  
G.L. Hunt ◽  
D. Heinemann ◽  
R.R. Veit ◽  
R.B. Heywood ◽  
I. Everson
Keyword(s):  
Community Structure ◽  
Drake Passage ◽  
Marine Birds ◽  
Bransfield Strait
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