On the meridional extent and fronts of the Antarctic Circumpolar Current

Orsi, Alejandro H.; Whitworth, Thomas; Nowlin, Worth D.

doi:10.1016/0967-0637(95)00021-w

Cited by 2,507 publications

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“…2 and 4. The insert map shows the location of Drift 7 at the continental margin of the Antarctic Peninsula (black box, bathymetry according to Smith and Sandwell, 1997) of the southern ACC front (dashed line, according to Orsi et al, 1995) and the inferred southwest setting bottom current (thin arrows, according to Giorgetti et al, 2003).…”

Section: Geological and Oceanographic Backgroundmentioning

confidence: 99%

“…Two oceanographic fronts are located directly west of the Antarctic Peninsula, the Polar Front in the north and the southern boundary of the ACC in the south (Orsi et al, 1995). The water column in the Bellingshausen Sea consists of a thin surface layer of cold Antarctic Surface Water (AASW) and underlying warm, saline Circumpolar Deep Water (CDW), which locally protrudes onto the shelf (e.g., Hofmann et al, 1996).…”

Section: Geological and Oceanographic Backgroundmentioning

confidence: 99%

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Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Uenzelmann-Neben

2006

Marine Geology

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Understanding the processes and phases of deep-sea sediment drift formation is essential for a reconstruction of their evolution. This leads to a better understanding of the properties of oceanographic currents active during drift formation and in turn to information on the climatic conditions. A system of sediment drifts at the Antarctic Peninsula Pacific rise has been chosen to learn more about the Neogene evolution of both current systems and palaeo-climate in that area. Drift 7 was extensively surveyed (seismic and sampling), and two ODP Leg 178 sites were drilled there. Using this information, maps of reflectors depth and seismic unit thickness were compiled and interpreted regarding the controlling depositional processes. The depositional model shows an initially major along-slope sediment transport by a SW-setting bottom current (25-15 Ma), which deflected sediment supplied from the continental shelf. Between 15 Ma and 9.5 Ma down-slope transport took over as a result of the growth of the Antarctic Peninsula ice sheet. The SW setting bottom current appears to have broken down. Down-slope transport has decreased since 9.5 Ma, but a re-onset of the bottom current can only be observed since 5.3 Ma. The analysis has further shown that the nucleus of the drift is connected to a basement ridge. It is hence inferred that basement topography played a major role in the formation of this sediment drift.

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Section: Geological and Oceanographic Backgroundmentioning

confidence: 99%

Section: Geological and Oceanographic Backgroundmentioning

confidence: 99%

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Uenzelmann-Neben

2006

Marine Geology

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“…The Antarctic Circumpolar Current frontal zones are functionally water mass boundaries, but their locations are highly variable (Orsi et al, 1995;Rintoul, 2009a, 2009b). From north to south they are: the sub-Antarctic Front, the Antarctic Polar Front, the Southern Antarctic Circumpolar Current Front, and the Southern Boundary of the Antarctic Circumpolar Current (Orsi et al, 1995).…”

Section: Physical Conditions and Circulation In The Antarcticmentioning

confidence: 99%

“…The Southern Ocean physically encompasses the region from the Antarctic continent north to the Subtropical Front, but here we mainly focus on the regions south of the Polar Front (Orsi et al, 1995). Bottom depths are typically 4000-5000 m, with relatively narrow but deep (50-800 m, mean 500 m) continental shelf regions (Fig.…”

Section: Introductionmentioning

confidence: 99%

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

Hunt

Drinkwater

Arrigo

et al. 2016

Progress in Oceanography

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a b s t r a c tWe compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal.In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal http://dx

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“…Today, Site U1356 lies close to the Southern Boundary of the Antarctic Circumpolar Current, near the Antarctic Divergence at ~63ºS (Orsi, 1995;Bindoff, 2000) (Fig. 1).…”

mentioning

confidence: 99%

Late Oligocene obliquity-paced contourite sedimentation in the Wilkes Land margin of East Antarctica: implications for paleoceanographic and ice sheet configurations

Salabarnada

Escutia

Röhl

et al. 2017

Preprint

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The late Oligocene experienced atmospheric concentrations of CO 2 between 400 and 750 ppm, which are within the IPCC projections for this century, assuming unabated CO 2 emissions. However, Antarctic Unlike today, the continental shelf was not over-deepened, and thus marine-based ice sheet expansion was likely limited to coastal regions. Combined, these data suggest that ice sheets in the Wilkes 60 Subglacial Basin were largely land-based, and therefore retreated as a consequence of surface melt during late Oligocene, rather than direct ocean forcing and marine ice sheet instability processes as it did in younger past warm intervals. Spectral analysis on late Oligocene sediments from the eastern Wilkes Land margin show that the glacial-interglacial cyclicity and resulting displacements of the Southern Ocean frontal systems between 26-25 Ma were forced by obliquity. 65Clim. Past Discuss., https://doi

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On the meridional extent and fronts of the Antarctic Circumpolar Current

Cited by 2,507 publications

References 40 publications

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

Late Oligocene obliquity-paced contourite sedimentation in the Wilkes Land margin of East Antarctica: implications for paleoceanographic and ice sheet configurations

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