Physical controls on biogeochemical zonation in the Southern Ocean
The primary control on the N–S zonation of the Southern Ocean is the wind-induced transport of the Antarctic Circumpolar Current (ACC). The ACC divides the Southern Ocean into three major zones: the Subantarctic Zone (SAZ) north of the ACC; the ACC transport zone; and the zone south of the ACC (SACC...
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ftnerc:oai:nora.nerc.ac.uk:106097 2023-05-15T13:45:12+02:00 Physical controls on biogeochemical zonation in the Southern Ocean Pollard, R.T. Lucas, M.I. Read, J.F. 2002 http://nora.nerc.ac.uk/id/eprint/106097/ https://doi.org/10.1016/S0967-0645(02)00084-X unknown Pollard, R.T.; Lucas, M.I.; Read, J.F. 2002 Physical controls on biogeochemical zonation in the Southern Ocean. Deep Sea Research Part II: Topical Studies in Oceanography, 49 (16). 3289-3305. https://doi.org/10.1016/S0967-0645(02)00084-X <https://doi.org/10.1016/S0967-0645(02)00084-X> Publication - Article PeerReviewed 2002 ftnerc https://doi.org/10.1016/S0967-0645(02)00084-X 2023-02-04T19:33:41Z The primary control on the N–S zonation of the Southern Ocean is the wind-induced transport of the Antarctic Circumpolar Current (ACC). The ACC divides the Southern Ocean into three major zones: the Subantarctic Zone (SAZ) north of the ACC; the ACC transport zone; and the zone south of the ACC (SACCZ). The zone of ACC transport is most often subdivided into two zones, the Polar Frontal Zone (PFZ) and the Antarctic Zone (AAZ), but it may be appropriate to define more subzones or indeed only one at some longitudes. To maintain geostrophic balance, isopycnals must slope upwards to the south across the ACC, thus raising nutrient-rich deep water closer to the surface as one goes polewards. In addition, silicate concentrations increase polewards along isopycnals because of diapycnic mixing with silicate-rich bottom water. Surface silicate concentrations therefore decrease northwards from high levels in the SACCZ to low levels in the SAZ. Within the SAZ and PFZ and even in the northern part of the AAZ, silicate levels may drop to limiting levels for siliceous phytoplankton production during summer. Nitrate concentrations also decrease northwards, but only become limiting in the Subtropical Zone north of the SAZ. The second circumpolar control is the changing balance of stratification, with temperature dominating near-surface stratification in the SAZ and salinity dominating further south because of fresh water input to the surface from melting ice. This results in circumpolar features such as the subsurface 2°C temperature minimum and the subduction of the salinity minimum of Antarctic Intermediate Water, which are often but not always associated with frontal jets and large transports. The transport of the ACC is dynamically constrained into narrow bands, the number and latitudinal location of which are controlled by the bathymetry and so vary with longitude. Thus it is not the fronts that are circumpolar, but the total ACC transport and scalar properties of the salinity and temperature fields. Evidence of summer ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean The Antarctic Deep Sea Research Part II: Topical Studies in Oceanography 49 16 3289 3305 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The primary control on the N–S zonation of the Southern Ocean is the wind-induced transport of the Antarctic Circumpolar Current (ACC). The ACC divides the Southern Ocean into three major zones: the Subantarctic Zone (SAZ) north of the ACC; the ACC transport zone; and the zone south of the ACC (SACCZ). The zone of ACC transport is most often subdivided into two zones, the Polar Frontal Zone (PFZ) and the Antarctic Zone (AAZ), but it may be appropriate to define more subzones or indeed only one at some longitudes. To maintain geostrophic balance, isopycnals must slope upwards to the south across the ACC, thus raising nutrient-rich deep water closer to the surface as one goes polewards. In addition, silicate concentrations increase polewards along isopycnals because of diapycnic mixing with silicate-rich bottom water. Surface silicate concentrations therefore decrease northwards from high levels in the SACCZ to low levels in the SAZ. Within the SAZ and PFZ and even in the northern part of the AAZ, silicate levels may drop to limiting levels for siliceous phytoplankton production during summer. Nitrate concentrations also decrease northwards, but only become limiting in the Subtropical Zone north of the SAZ. The second circumpolar control is the changing balance of stratification, with temperature dominating near-surface stratification in the SAZ and salinity dominating further south because of fresh water input to the surface from melting ice. This results in circumpolar features such as the subsurface 2°C temperature minimum and the subduction of the salinity minimum of Antarctic Intermediate Water, which are often but not always associated with frontal jets and large transports. The transport of the ACC is dynamically constrained into narrow bands, the number and latitudinal location of which are controlled by the bathymetry and so vary with longitude. Thus it is not the fronts that are circumpolar, but the total ACC transport and scalar properties of the salinity and temperature fields. Evidence of summer ... |
format |
Article in Journal/Newspaper |
author |
Pollard, R.T. Lucas, M.I. Read, J.F. |
spellingShingle |
Pollard, R.T. Lucas, M.I. Read, J.F. Physical controls on biogeochemical zonation in the Southern Ocean |
author_facet |
Pollard, R.T. Lucas, M.I. Read, J.F. |
author_sort |
Pollard, R.T. |
title |
Physical controls on biogeochemical zonation in the Southern Ocean |
title_short |
Physical controls on biogeochemical zonation in the Southern Ocean |
title_full |
Physical controls on biogeochemical zonation in the Southern Ocean |
title_fullStr |
Physical controls on biogeochemical zonation in the Southern Ocean |
title_full_unstemmed |
Physical controls on biogeochemical zonation in the Southern Ocean |
title_sort |
physical controls on biogeochemical zonation in the southern ocean |
publishDate |
2002 |
url |
http://nora.nerc.ac.uk/id/eprint/106097/ https://doi.org/10.1016/S0967-0645(02)00084-X |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
Pollard, R.T.; Lucas, M.I.; Read, J.F. 2002 Physical controls on biogeochemical zonation in the Southern Ocean. Deep Sea Research Part II: Topical Studies in Oceanography, 49 (16). 3289-3305. https://doi.org/10.1016/S0967-0645(02)00084-X <https://doi.org/10.1016/S0967-0645(02)00084-X> |
op_doi |
https://doi.org/10.1016/S0967-0645(02)00084-X |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
49 |
container_issue |
16 |
container_start_page |
3289 |
op_container_end_page |
3305 |
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