Nutrient irrigation of the North Atlantic
The North Atlantic, as all major oceans, has a remarkable duality in primary production, manifested by the existence of well-defined high and low mean primary production regions. The largest region is the North Atlantic Subtropical Gyre (NASTG), an anticyclone characterized by bowl shaped isopycnals...
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Online Access: | http://hdl.handle.net/10553/48372 https://doi.org/10.1016/j.pocean.2006.03.018 |
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ftunivlaspalmas:oai:https://accedacris.ulpgc.es:10553/48372 2023-05-15T17:29:02+02:00 Nutrient irrigation of the North Atlantic Pelegrí Llopart,José Luis Marrero-Díaz, A. Ratsimandresy, A. W. Pelegri, Josep Marrero-Diaz, Angeles 7003869003 6507074043 6506010713 358123 1846069 2309868 2006 http://hdl.handle.net/10553/48372 https://doi.org/10.1016/j.pocean.2006.03.018 eng eng 0079-6611 Progress in Oceanography 0079-6611 http://hdl.handle.net/10553/48372 doi:10.1016/j.pocean.2006.03.018 33646593748 000241170000016 406 366 70 L-5815-2014 H-2175-2015 Progress in Oceanography [ISSN 0079-6611], v. 70, p. 366-406 2510 Oceanografía Nutrient cycles Subtropical zone Isopycnals North Atlantic Gulf stream Upwelling 2006 ftunivlaspalmas https://doi.org/10.1016/j.pocean.2006.03.018 2020-01-29T00:08:01Z The North Atlantic, as all major oceans, has a remarkable duality in primary production, manifested by the existence of well-defined high and low mean primary production regions. The largest region is the North Atlantic Subtropical Gyre (NASTG), an anticyclone characterized by bowl shaped isopycnals and low production. The NASTG is surrounded at its margins by smaller cyclonic high-production regions, where these isopycnals approach the sea surface. The most extensive cyclonic regions are those at the latitudinal extremes, i.e. the subpolar and tropical oceans, though smaller ones do occur at the zonal boundaries. In this article we review historical data and present new analyses of climatological data and a selected number of hydrographic cruises in the western/northwestern and eastern/southeastern boundaries of the NASTG, with the objective of investigating the importance of upward epipycnal advection of nutrient-rich subsurface layers (irrigation) in maintaining high primary production in the euphotic layers. In the North Atlantic Subpolar Gyre (NASPG) irrigation implies intergyre exchange caused by the outcropping extension of the Gulf Stream (GS), following the formation of the deep winter mixed-layer. In the eastern boundary of the NASTG irrigation is attained through a permanent upwelling cell, which feeds the Canary Upwelling Current (CUC). In the southeastern corner irrigation occurs in fall, when the Guinea Dome (GD) is reinforced, and in winter, when the CUC reaches its southernmost extension. Other characteristics of the north/south extension of the GS/CUC are the seasonal nutrient replenishing of subsurface layers (spring restratification of NASPG and winter relaxation of the GD) and the maintenance of high levels of diapycnal mixing during the last phase of nutrient transfer to the euphotic layers. Off the Mid-Atlantic Bight the GS transports a total of about 700 kmol s−1 of nitrate, with almost 100 kmol s−1 carried in the surface (σθ < 26.8) layers and some 350 kmol s−1 in the intermediate (26.8 < σθ < 27.5) layers. A box model suggests that north of Cape Hatteras most surface and upper-thermocline nitrates are used to sustain the high levels of primary production in the NASPG. Off Cape Blanc there is winter along-shore convergence of order 10 kmol s−1 of nitrate in the near-surface layers (possibly larger in summer), with only a small fraction used to sustain local primary production in the coastal upwelling band and the remainder carried to the interior ocean. Nutrients and biomass exported from these cyclonic regions may account for the concentration levels observed within the NASTG. Other/Unknown Material North Atlantic Universidad de Las Palmas de Gran Canaria: Acceda Progress in Oceanography 70 2-4 366 406 |
institution |
Open Polar |
collection |
Universidad de Las Palmas de Gran Canaria: Acceda |
op_collection_id |
ftunivlaspalmas |
language |
English |
topic |
2510 Oceanografía Nutrient cycles Subtropical zone Isopycnals North Atlantic Gulf stream Upwelling |
spellingShingle |
2510 Oceanografía Nutrient cycles Subtropical zone Isopycnals North Atlantic Gulf stream Upwelling Pelegrí Llopart,José Luis Marrero-Díaz, A. Ratsimandresy, A. W. Nutrient irrigation of the North Atlantic |
topic_facet |
2510 Oceanografía Nutrient cycles Subtropical zone Isopycnals North Atlantic Gulf stream Upwelling |
description |
The North Atlantic, as all major oceans, has a remarkable duality in primary production, manifested by the existence of well-defined high and low mean primary production regions. The largest region is the North Atlantic Subtropical Gyre (NASTG), an anticyclone characterized by bowl shaped isopycnals and low production. The NASTG is surrounded at its margins by smaller cyclonic high-production regions, where these isopycnals approach the sea surface. The most extensive cyclonic regions are those at the latitudinal extremes, i.e. the subpolar and tropical oceans, though smaller ones do occur at the zonal boundaries. In this article we review historical data and present new analyses of climatological data and a selected number of hydrographic cruises in the western/northwestern and eastern/southeastern boundaries of the NASTG, with the objective of investigating the importance of upward epipycnal advection of nutrient-rich subsurface layers (irrigation) in maintaining high primary production in the euphotic layers. In the North Atlantic Subpolar Gyre (NASPG) irrigation implies intergyre exchange caused by the outcropping extension of the Gulf Stream (GS), following the formation of the deep winter mixed-layer. In the eastern boundary of the NASTG irrigation is attained through a permanent upwelling cell, which feeds the Canary Upwelling Current (CUC). In the southeastern corner irrigation occurs in fall, when the Guinea Dome (GD) is reinforced, and in winter, when the CUC reaches its southernmost extension. Other characteristics of the north/south extension of the GS/CUC are the seasonal nutrient replenishing of subsurface layers (spring restratification of NASPG and winter relaxation of the GD) and the maintenance of high levels of diapycnal mixing during the last phase of nutrient transfer to the euphotic layers. Off the Mid-Atlantic Bight the GS transports a total of about 700 kmol s−1 of nitrate, with almost 100 kmol s−1 carried in the surface (σθ < 26.8) layers and some 350 kmol s−1 in the intermediate (26.8 < σθ < 27.5) layers. A box model suggests that north of Cape Hatteras most surface and upper-thermocline nitrates are used to sustain the high levels of primary production in the NASPG. Off Cape Blanc there is winter along-shore convergence of order 10 kmol s−1 of nitrate in the near-surface layers (possibly larger in summer), with only a small fraction used to sustain local primary production in the coastal upwelling band and the remainder carried to the interior ocean. Nutrients and biomass exported from these cyclonic regions may account for the concentration levels observed within the NASTG. |
author2 |
Pelegri, Josep Marrero-Diaz, Angeles 7003869003 6507074043 6506010713 358123 1846069 2309868 |
author |
Pelegrí Llopart,José Luis Marrero-Díaz, A. Ratsimandresy, A. W. |
author_facet |
Pelegrí Llopart,José Luis Marrero-Díaz, A. Ratsimandresy, A. W. |
author_sort |
Pelegrí Llopart,José Luis |
title |
Nutrient irrigation of the North Atlantic |
title_short |
Nutrient irrigation of the North Atlantic |
title_full |
Nutrient irrigation of the North Atlantic |
title_fullStr |
Nutrient irrigation of the North Atlantic |
title_full_unstemmed |
Nutrient irrigation of the North Atlantic |
title_sort |
nutrient irrigation of the north atlantic |
publisher |
0079-6611 |
publishDate |
2006 |
url |
http://hdl.handle.net/10553/48372 https://doi.org/10.1016/j.pocean.2006.03.018 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Progress in Oceanography [ISSN 0079-6611], v. 70, p. 366-406 |
op_relation |
Progress in Oceanography 0079-6611 http://hdl.handle.net/10553/48372 doi:10.1016/j.pocean.2006.03.018 33646593748 000241170000016 406 366 70 L-5815-2014 H-2175-2015 |
op_doi |
https://doi.org/10.1016/j.pocean.2006.03.018 |
container_title |
Progress in Oceanography |
container_volume |
70 |
container_issue |
2-4 |
container_start_page |
366 |
op_container_end_page |
406 |
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1766122344525332480 |