Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica
Formation of dense shelf water (DSW) in coastal polynyas (open water or thin sea-ice cover) in the sea-ice zone around Antarctica supplies Antarctic Bottom Water (AABW) through overflow down the continental slope. In coastal polynyas, atmospheric carbon dioxide (CO2) is absorbed by the ocean in the...
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Online Access: | http://hdl.handle.net/2115/86808 https://doi.org/10.1016/j.marchem.2020.103842 |
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/86808 2023-05-15T13:51:33+02:00 Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica Kan, Murakami Daiki, Nomura Gen, Hashida Nakaoka, Shin-ichiro Kitade, Yujiro Hirano, Daisuke Hirawake, Toru Ohshima, Kay I. http://hdl.handle.net/2115/86808 https://doi.org/10.1016/j.marchem.2020.103842 eng eng Elsevier http://hdl.handle.net/2115/86808 Marine Chemistry, 225: 103842 http://dx.doi.org/10.1016/j.marchem.2020.103842 © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ https://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Carbon dioxide Primary production Carbon transport Dense water formation Gas exchange Polynya Cape Darnley Southern Ocean 430 article (author version) fthokunivhus https://doi.org/10.1016/j.marchem.2020.103842 2022-11-18T01:06:02Z Formation of dense shelf water (DSW) in coastal polynyas (open water or thin sea-ice cover) in the sea-ice zone around Antarctica supplies Antarctic Bottom Water (AABW) through overflow down the continental slope. In coastal polynyas, atmospheric carbon dioxide (CO2) is absorbed by the ocean in the early spring because of active primary production, and DSW formation is an important process for transporting this carbon from the sea surface to the deep ocean. However, there have been few quantitative evaluations of carbon consumption by active primary production and transport in coastal polynyas. Here, we examined the carbon dynamics in the Cape Darnley polynya (CDP), East Antarctica during austral summer 2009, by using carbonate system parameters combined with oceanographic mooring data. The partial pressure of CO2 in the CDP surface water was lower than that of the atmosphere and the mean and standard deviation of sea−air CO2 flux was estimated as −6.5 ± 6.9 mmol C m−2 d−1 (a negative value indicates absorption of atmospheric CO2 by the ocean). Vertical profiles of dissolved inorganic carbon (DIC) concentration showed that concentrations in the bottom layer near the ocean floor were lower (by about 20 μmol kg−1) than those in the ambient water (e.g., modified Circumpolar Deep Water, mCDW). The low-DIC in the shelf water was maintained by the strong biological uptake of carbon imported from high-DIC mCDW within the water column. Therefore, low-DIC DSW overflowed down the continental slope, and low-DIC concentrations were maintained through an export pathway to the continental shelf. The annual production of dissolved organic carbon and particulate organic carbon on the shelf was estimated as 0.7 × 1011–1.5 × 1011 mol C using the data for the DIC of DSW and current velocity data from a mooring in the CDP. Our results provide quantitative estimates for the potential role of carbon consumption by the active primary production and carbon transport by dense water formation in Antarctic coastal polynyas. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Antarctic Austral Cape Darnley ENVELOPE(69.567,69.567,-67.738,-67.738) Darnley ENVELOPE(69.717,69.717,-67.717,-67.717) East Antarctica Southern Ocean Marine Chemistry 225 103842 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
Carbon dioxide Primary production Carbon transport Dense water formation Gas exchange Polynya Cape Darnley Southern Ocean 430 |
spellingShingle |
Carbon dioxide Primary production Carbon transport Dense water formation Gas exchange Polynya Cape Darnley Southern Ocean 430 Kan, Murakami Daiki, Nomura Gen, Hashida Nakaoka, Shin-ichiro Kitade, Yujiro Hirano, Daisuke Hirawake, Toru Ohshima, Kay I. Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
topic_facet |
Carbon dioxide Primary production Carbon transport Dense water formation Gas exchange Polynya Cape Darnley Southern Ocean 430 |
description |
Formation of dense shelf water (DSW) in coastal polynyas (open water or thin sea-ice cover) in the sea-ice zone around Antarctica supplies Antarctic Bottom Water (AABW) through overflow down the continental slope. In coastal polynyas, atmospheric carbon dioxide (CO2) is absorbed by the ocean in the early spring because of active primary production, and DSW formation is an important process for transporting this carbon from the sea surface to the deep ocean. However, there have been few quantitative evaluations of carbon consumption by active primary production and transport in coastal polynyas. Here, we examined the carbon dynamics in the Cape Darnley polynya (CDP), East Antarctica during austral summer 2009, by using carbonate system parameters combined with oceanographic mooring data. The partial pressure of CO2 in the CDP surface water was lower than that of the atmosphere and the mean and standard deviation of sea−air CO2 flux was estimated as −6.5 ± 6.9 mmol C m−2 d−1 (a negative value indicates absorption of atmospheric CO2 by the ocean). Vertical profiles of dissolved inorganic carbon (DIC) concentration showed that concentrations in the bottom layer near the ocean floor were lower (by about 20 μmol kg−1) than those in the ambient water (e.g., modified Circumpolar Deep Water, mCDW). The low-DIC in the shelf water was maintained by the strong biological uptake of carbon imported from high-DIC mCDW within the water column. Therefore, low-DIC DSW overflowed down the continental slope, and low-DIC concentrations were maintained through an export pathway to the continental shelf. The annual production of dissolved organic carbon and particulate organic carbon on the shelf was estimated as 0.7 × 1011–1.5 × 1011 mol C using the data for the DIC of DSW and current velocity data from a mooring in the CDP. Our results provide quantitative estimates for the potential role of carbon consumption by the active primary production and carbon transport by dense water formation in Antarctic coastal polynyas. |
format |
Article in Journal/Newspaper |
author |
Kan, Murakami Daiki, Nomura Gen, Hashida Nakaoka, Shin-ichiro Kitade, Yujiro Hirano, Daisuke Hirawake, Toru Ohshima, Kay I. |
author_facet |
Kan, Murakami Daiki, Nomura Gen, Hashida Nakaoka, Shin-ichiro Kitade, Yujiro Hirano, Daisuke Hirawake, Toru Ohshima, Kay I. |
author_sort |
Kan, Murakami |
title |
Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
title_short |
Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
title_full |
Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
title_fullStr |
Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
title_full_unstemmed |
Strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the Cape Darnley polynya, East Antarctica |
title_sort |
strong biological carbon uptake and carbonate chemistry associated with dense shelf water outflows in the cape darnley polynya, east antarctica |
publisher |
Elsevier |
url |
http://hdl.handle.net/2115/86808 https://doi.org/10.1016/j.marchem.2020.103842 |
long_lat |
ENVELOPE(69.567,69.567,-67.738,-67.738) ENVELOPE(69.717,69.717,-67.717,-67.717) |
geographic |
Antarctic Austral Cape Darnley Darnley East Antarctica Southern Ocean |
geographic_facet |
Antarctic Austral Cape Darnley Darnley East Antarctica Southern Ocean |
genre |
Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean |
op_relation |
http://hdl.handle.net/2115/86808 Marine Chemistry, 225: 103842 http://dx.doi.org/10.1016/j.marchem.2020.103842 |
op_rights |
© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1016/j.marchem.2020.103842 |
container_title |
Marine Chemistry |
container_volume |
225 |
container_start_page |
103842 |
_version_ |
1766255455182520320 |