Circumpolar deep water and shelf sediments support late summer microbial iron remineralization
Despite widespread iron (Fe) limitation in the Southern Ocean, intense phytoplankton blooms are observed around productive coastal regions such as the Mertz Polynya (off George V Land and Adelie Land, East Antarctica; 140-155 degrees E). Sources of Fe across coastal East Antarctica vary, with limite...
Published in: | Global Biogeochemical Cycles |
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Online Access: | https://doi.org/10.1029/2020GB006921 http://ecite.utas.edu.au/152328 |
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ftunivtasecite:oai:ecite.utas.edu.au:152328 2023-05-15T13:04:18+02:00 Circumpolar deep water and shelf sediments support late summer microbial iron remineralization Smith, AJR Ratnarajah, L Holmes, TM Wuttig, K Townsend, AT Westwood, K Cox, MJ Bell, E Nicol, S Lannuzel, D 2021 application/pdf https://doi.org/10.1029/2020GB006921 http://ecite.utas.edu.au/152328 en eng Wiley-Blackwell Verlag GmbH http://ecite.utas.edu.au/152328/1/152328 - Circumpolar deep water.pdf http://dx.doi.org/10.1029/2020GB006921 Smith, AJR and Ratnarajah, L and Holmes, TM and Wuttig, K and Townsend, AT and Westwood, K and Cox, MJ and Bell, E and Nicol, S and Lannuzel, D, Circumpolar deep water and shelf sediments support late summer microbial iron remineralization, Global Biogeochemical Cycles, 35, (11) Article 2020GB006921. ISSN 0886-6236 (2021) [Refereed Article] http://ecite.utas.edu.au/152328 Biological Sciences Ecology Marine and estuarine ecology (incl. marine ichthyology) Refereed Article PeerReviewed 2021 ftunivtasecite https://doi.org/10.1029/2020GB006921 2022-12-12T23:17:15Z Despite widespread iron (Fe) limitation in the Southern Ocean, intense phytoplankton blooms are observed around productive coastal regions such as the Mertz Polynya (off George V Land and Adelie Land, East Antarctica; 140-155 degrees E). Sources of Fe across coastal East Antarctica vary, with limited data available for late summer months. We investigated the sources of dissolved Fe (dFe; <0.2 mu m) at 19 oceanographic stations in the Mertz Glacier Region (64-67 degrees S; 138-154 degrees E), between January and March of 2019. Concentrations of dFe ranged from below detection limit (0.03 nM) at the surface, to 0.34 nM above the base of the mixed layer (35 m), reaching 0.59 nM at depth (520 m). Using oceanographic features and trace element ratios (manganese and titanium), we identified Circumpolar Deep Water (CDW) and shelf sediment resuspension in modified CDW as contributors of dFe to the region over this period. Microbial Fe remineralization was evident where nutrient-rich water met highly oxygenated waters over the continental shelf. Reduced Fe concentrations in the mixed layer and euphotic zones suggested rapid biological uptake prior to sampling. Despite proposals for pelagic Fe recycling by marine animals, preliminary investigations reveal no significant spatial relationship between animal presence and surface ocean Fe concentrations over the study area. Further research is required to identify seasonal changes to Fe supply in coastal areas which will strengthen our understanding of the Fe cycle and its influence on microbial and primary productivity in this globally significant region. Article in Journal/Newspaper Adelie Land Antarc* Antarctica East Antarctica George V Land Mertz Glacier Southern Ocean eCite UTAS (University of Tasmania) Southern Ocean East Antarctica Mertz Glacier ENVELOPE(144.500,144.500,-67.667,-67.667) George V Land ENVELOPE(148.000,148.000,-68.500,-68.500) Global Biogeochemical Cycles 35 11 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Biological Sciences Ecology Marine and estuarine ecology (incl. marine ichthyology) |
spellingShingle |
Biological Sciences Ecology Marine and estuarine ecology (incl. marine ichthyology) Smith, AJR Ratnarajah, L Holmes, TM Wuttig, K Townsend, AT Westwood, K Cox, MJ Bell, E Nicol, S Lannuzel, D Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
topic_facet |
Biological Sciences Ecology Marine and estuarine ecology (incl. marine ichthyology) |
description |
Despite widespread iron (Fe) limitation in the Southern Ocean, intense phytoplankton blooms are observed around productive coastal regions such as the Mertz Polynya (off George V Land and Adelie Land, East Antarctica; 140-155 degrees E). Sources of Fe across coastal East Antarctica vary, with limited data available for late summer months. We investigated the sources of dissolved Fe (dFe; <0.2 mu m) at 19 oceanographic stations in the Mertz Glacier Region (64-67 degrees S; 138-154 degrees E), between January and March of 2019. Concentrations of dFe ranged from below detection limit (0.03 nM) at the surface, to 0.34 nM above the base of the mixed layer (35 m), reaching 0.59 nM at depth (520 m). Using oceanographic features and trace element ratios (manganese and titanium), we identified Circumpolar Deep Water (CDW) and shelf sediment resuspension in modified CDW as contributors of dFe to the region over this period. Microbial Fe remineralization was evident where nutrient-rich water met highly oxygenated waters over the continental shelf. Reduced Fe concentrations in the mixed layer and euphotic zones suggested rapid biological uptake prior to sampling. Despite proposals for pelagic Fe recycling by marine animals, preliminary investigations reveal no significant spatial relationship between animal presence and surface ocean Fe concentrations over the study area. Further research is required to identify seasonal changes to Fe supply in coastal areas which will strengthen our understanding of the Fe cycle and its influence on microbial and primary productivity in this globally significant region. |
format |
Article in Journal/Newspaper |
author |
Smith, AJR Ratnarajah, L Holmes, TM Wuttig, K Townsend, AT Westwood, K Cox, MJ Bell, E Nicol, S Lannuzel, D |
author_facet |
Smith, AJR Ratnarajah, L Holmes, TM Wuttig, K Townsend, AT Westwood, K Cox, MJ Bell, E Nicol, S Lannuzel, D |
author_sort |
Smith, AJR |
title |
Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
title_short |
Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
title_full |
Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
title_fullStr |
Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
title_full_unstemmed |
Circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
title_sort |
circumpolar deep water and shelf sediments support late summer microbial iron remineralization |
publisher |
Wiley-Blackwell Verlag GmbH |
publishDate |
2021 |
url |
https://doi.org/10.1029/2020GB006921 http://ecite.utas.edu.au/152328 |
long_lat |
ENVELOPE(144.500,144.500,-67.667,-67.667) ENVELOPE(148.000,148.000,-68.500,-68.500) |
geographic |
Southern Ocean East Antarctica Mertz Glacier George V Land |
geographic_facet |
Southern Ocean East Antarctica Mertz Glacier George V Land |
genre |
Adelie Land Antarc* Antarctica East Antarctica George V Land Mertz Glacier Southern Ocean |
genre_facet |
Adelie Land Antarc* Antarctica East Antarctica George V Land Mertz Glacier Southern Ocean |
op_relation |
http://ecite.utas.edu.au/152328/1/152328 - Circumpolar deep water.pdf http://dx.doi.org/10.1029/2020GB006921 Smith, AJR and Ratnarajah, L and Holmes, TM and Wuttig, K and Townsend, AT and Westwood, K and Cox, MJ and Bell, E and Nicol, S and Lannuzel, D, Circumpolar deep water and shelf sediments support late summer microbial iron remineralization, Global Biogeochemical Cycles, 35, (11) Article 2020GB006921. ISSN 0886-6236 (2021) [Refereed Article] http://ecite.utas.edu.au/152328 |
op_doi |
https://doi.org/10.1029/2020GB006921 |
container_title |
Global Biogeochemical Cycles |
container_volume |
35 |
container_issue |
11 |
_version_ |
1766356899462119424 |