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Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea

Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea
Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea

The Antarctic Peninsula (AP) shelf is an important source of dissolved iron (Fe) to the upper ocean in the southern Scotia Sea, one of the most productive regions of the Southern Ocean. Here we present results from a four-year (2003-2006) numerical simulation using a regional coupled physical-biogeochemical model to assess the Fe sources and transport on the AP shelf and toward the southern Scotia Sea. The model was validated with a suite of data derived from in situ surveys and remote sensing. Model results indicate that sediments in the AP shelf and the South Orkney Plateau (SOP) provide the dominant source of Fe to the upper 500 m in the southern Scotia Sea. Additional Fe inputs to the region are associated with the Antarctic Circumpolar Current (ACC) and the northern limb of the Weddell Gyre, deep-ocean sediment sources, dust deposition, and icebergs. Fe on the AP shelf originates primarily from sediments on the relatively shallow inner shelf and is directly injected into the water column and subsequently transported toward Elephant Island by the confluent shelf currents. Off-shelf Fe export is primarily through entrainment of shelf waters by the ACC's Southern Boundary frontal jet along the northern edge of the AP shelf, the Hesperides Trough, and the SOP shelf. About 70% of the off-shelf export takes place below the surface mixed layer, and is subsequently re-supplied to the euphotic zone through vertical mixing, mainly during austral fall and winter. The exported shelf-derived Fe is then advected downstream by the ACC and Weddell Gyre and spread over the southern and eastern Scotia Seas. Taken together, shelf Fe export witin top 500 m meets nearly all of the Fe demand of phytoplankton photosynthesis in the southern Scotia Sea. Waters with elevated Fe concentrations in the Scotia Sea are largely restricted to south of the Southern ACC Front.

Antarctic Peninsula, Coupled physical-biogeochemical model, Iron (Fe), Off-shelf transport, Shelf sediment, Southern Scotia Sea
0967-0637
Jiang, Mingshun
b8f22586-c30b-4675-ba77-55995254ee38
Measures, Christopher I.
209779b6-4c8e-47e0-8c74-d673678a65d0
Barbeau, Katherine A.
fdb98ee5-2486-4da7-a728-41c5d018edd1
Charette, Matthew A.
afe63d56-266a-4819-9dfb-2669ffb204e7
Gille, Sarah T.
6685a419-8041-49eb-98e5-b54d7aef90ec
Hatta, Mariko
b8c210ca-90aa-4660-b1b7-3538b120e31d
Kahru, Mati
15e387a7-4eee-43ab-9b05-00e117f6164f
Mitchell, B. Gregory
e4cd75cf-aac0-4cd3-bbaa-87cea79782f9
Naveira Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Reiss, Christian
f8b71445-ede5-4a98-9362-9a1bea0984c7
Selph, Karen
70cbf564-8633-4fae-896d-c0aebbc3705a
Zhou, Meng
60ec9bbc-921b-4489-a336-43157df5fd7f
Jiang, Mingshun
b8f22586-c30b-4675-ba77-55995254ee38
Measures, Christopher I.
209779b6-4c8e-47e0-8c74-d673678a65d0
Barbeau, Katherine A.
fdb98ee5-2486-4da7-a728-41c5d018edd1
Charette, Matthew A.
afe63d56-266a-4819-9dfb-2669ffb204e7
Gille, Sarah T.
6685a419-8041-49eb-98e5-b54d7aef90ec
Hatta, Mariko
b8c210ca-90aa-4660-b1b7-3538b120e31d
Kahru, Mati
15e387a7-4eee-43ab-9b05-00e117f6164f
Mitchell, B. Gregory
e4cd75cf-aac0-4cd3-bbaa-87cea79782f9
Naveira Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Reiss, Christian
f8b71445-ede5-4a98-9362-9a1bea0984c7
Selph, Karen
70cbf564-8633-4fae-896d-c0aebbc3705a
Zhou, Meng
60ec9bbc-921b-4489-a336-43157df5fd7f

Jiang, Mingshun, Measures, Christopher I., Barbeau, Katherine A., Charette, Matthew A., Gille, Sarah T., Hatta, Mariko, Kahru, Mati, Mitchell, B. Gregory, Naveira Garabato, Alberto C., Reiss, Christian, Selph, Karen and Zhou, Meng (2019) Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea. Deep-Sea Research Part I: Oceanographic Research Papers. (doi:10.1016/j.dsr.2019.06.006).

Record type: Article

Abstract

The Antarctic Peninsula (AP) shelf is an important source of dissolved iron (Fe) to the upper ocean in the southern Scotia Sea, one of the most productive regions of the Southern Ocean. Here we present results from a four-year (2003-2006) numerical simulation using a regional coupled physical-biogeochemical model to assess the Fe sources and transport on the AP shelf and toward the southern Scotia Sea. The model was validated with a suite of data derived from in situ surveys and remote sensing. Model results indicate that sediments in the AP shelf and the South Orkney Plateau (SOP) provide the dominant source of Fe to the upper 500 m in the southern Scotia Sea. Additional Fe inputs to the region are associated with the Antarctic Circumpolar Current (ACC) and the northern limb of the Weddell Gyre, deep-ocean sediment sources, dust deposition, and icebergs. Fe on the AP shelf originates primarily from sediments on the relatively shallow inner shelf and is directly injected into the water column and subsequently transported toward Elephant Island by the confluent shelf currents. Off-shelf Fe export is primarily through entrainment of shelf waters by the ACC's Southern Boundary frontal jet along the northern edge of the AP shelf, the Hesperides Trough, and the SOP shelf. About 70% of the off-shelf export takes place below the surface mixed layer, and is subsequently re-supplied to the euphotic zone through vertical mixing, mainly during austral fall and winter. The exported shelf-derived Fe is then advected downstream by the ACC and Weddell Gyre and spread over the southern and eastern Scotia Seas. Taken together, shelf Fe export witin top 500 m meets nearly all of the Fe demand of phytoplankton photosynthesis in the southern Scotia Sea. Waters with elevated Fe concentrations in the Scotia Sea are largely restricted to south of the Southern ACC Front.

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Fe_transport_Dec18_2018 - Accepted Manuscript
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More information

Accepted/In Press date: 14 June 2019
e-pub ahead of print date: 19 June 2019
Keywords: Antarctic Peninsula, Coupled physical-biogeochemical model, Iron (Fe), Off-shelf transport, Shelf sediment, Southern Scotia Sea

Identifiers

Local EPrints ID: 432713
URI: http://eprints.soton.ac.uk/id/eprint/432713
ISSN: 0967-0637
PURE UUID: fb2e1196-4ec9-4c37-b6d4-55fca62d8c45

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Date deposited: 24 Jul 2019 16:30
Last modified: 07 Oct 2020 06:42

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