Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland
Glacial fjords in Greenland show high productivity owing to the runoff of meltwater from the glaciers. Macronutrient dynamics (of nitrate, phosphate, and silicate) associated with subglacial discharge plumes in front of marine-terminating glaciers are widely cited as important drivers of summer phyt...
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Online Access: | http://hdl.handle.net/2115/79982 https://doi.org/10.1029/2020GB006567 |
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/79982 2023-05-15T15:12:53+02:00 Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland Kanna, Naoya Sugiyama, Shin Fukamachi, Yasushi Nomura, Daiki Nishioka, Jun http://hdl.handle.net/2115/79982 https://doi.org/10.1029/2020GB006567 eng eng American Geophysical Union http://hdl.handle.net/2115/79982 Global Biogeochemical Cycles, 34(10): e2020GB006567 http://dx.doi.org/10.1029/2020GB006567 https://creativecommons.org/licenses/by/4.0/ CC-BY 450 article fthokunivhus https://doi.org/10.1029/2020GB006567 2022-11-18T01:06:12Z Glacial fjords in Greenland show high productivity owing to the runoff of meltwater from the glaciers. Macronutrient dynamics (of nitrate, phosphate, and silicate) associated with subglacial discharge plumes in front of marine-terminating glaciers are widely cited as important drivers of summer phytoplankton blooms in the fjords. However, the dynamics of iron (Fe), an essential micronutrient for primary production, remain largely unstudied in glacial fjords. To investigate the role of subglacial discharge plumes in Fe supply processes in glacial fjords, a comprehensive survey of Bowdoin Fjord, adjacent to the marine-terminating Bowdoin Glacier in northwestern Greenland, was conducted. The subglacial discharge of Fe-rich meltwater induces a buoyancy-driven upwelling plume in front of the glacier that entrains nutrient-rich Arctic- and Atlantic-origin waters. The plume water potentially carried 4.5-8.7 x 10(7) g day(-1) of total dissolvable Fe out of Bowdoin Fjord in summer. The concentration of dissolved Fe (dFe) in the plume water (similar to 15.6 nmol kg(-1)) was 4 times higher than that in the water in the outer part of the fjord (similar to 3.8 nmol kg(-1)). The dFe:nitrate + nitrite ratio (mmol mol(-1)) in the plume water varied between 0.58 and 3.2, several orders of magnitude higher than the phytoplankton cellular Fe:nitrate ratio estimated using the hypothetical Fe:C ratio and observed particulate organic carbon:nitrate ratio of the fjord. Hence, the plume water is replete with Fe with respect to phytoplankton demands. Subglacial discharge drives the upwelling of Fe and macronutrients toward the euphotic zone, which is vital for the generation of summer phytoplankton growth in glacial fjords. Article in Journal/Newspaper Arctic glacier Greenland Phytoplankton Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Arctic Greenland Bowdoin ENVELOPE(-69.317,-69.317,77.683,77.683) Bowdoin Fjord ENVELOPE(-68.521,-68.521,77.598,77.598) Global Biogeochemical Cycles 34 10 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
450 |
spellingShingle |
450 Kanna, Naoya Sugiyama, Shin Fukamachi, Yasushi Nomura, Daiki Nishioka, Jun Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
topic_facet |
450 |
description |
Glacial fjords in Greenland show high productivity owing to the runoff of meltwater from the glaciers. Macronutrient dynamics (of nitrate, phosphate, and silicate) associated with subglacial discharge plumes in front of marine-terminating glaciers are widely cited as important drivers of summer phytoplankton blooms in the fjords. However, the dynamics of iron (Fe), an essential micronutrient for primary production, remain largely unstudied in glacial fjords. To investigate the role of subglacial discharge plumes in Fe supply processes in glacial fjords, a comprehensive survey of Bowdoin Fjord, adjacent to the marine-terminating Bowdoin Glacier in northwestern Greenland, was conducted. The subglacial discharge of Fe-rich meltwater induces a buoyancy-driven upwelling plume in front of the glacier that entrains nutrient-rich Arctic- and Atlantic-origin waters. The plume water potentially carried 4.5-8.7 x 10(7) g day(-1) of total dissolvable Fe out of Bowdoin Fjord in summer. The concentration of dissolved Fe (dFe) in the plume water (similar to 15.6 nmol kg(-1)) was 4 times higher than that in the water in the outer part of the fjord (similar to 3.8 nmol kg(-1)). The dFe:nitrate + nitrite ratio (mmol mol(-1)) in the plume water varied between 0.58 and 3.2, several orders of magnitude higher than the phytoplankton cellular Fe:nitrate ratio estimated using the hypothetical Fe:C ratio and observed particulate organic carbon:nitrate ratio of the fjord. Hence, the plume water is replete with Fe with respect to phytoplankton demands. Subglacial discharge drives the upwelling of Fe and macronutrients toward the euphotic zone, which is vital for the generation of summer phytoplankton growth in glacial fjords. |
format |
Article in Journal/Newspaper |
author |
Kanna, Naoya Sugiyama, Shin Fukamachi, Yasushi Nomura, Daiki Nishioka, Jun |
author_facet |
Kanna, Naoya Sugiyama, Shin Fukamachi, Yasushi Nomura, Daiki Nishioka, Jun |
author_sort |
Kanna, Naoya |
title |
Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
title_short |
Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
title_full |
Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
title_fullStr |
Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
title_full_unstemmed |
Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine-Terminating Glacier in Northwestern Greenland |
title_sort |
iron supply by subglacial discharge into a fjord near the front of a marine-terminating glacier in northwestern greenland |
publisher |
American Geophysical Union |
url |
http://hdl.handle.net/2115/79982 https://doi.org/10.1029/2020GB006567 |
long_lat |
ENVELOPE(-69.317,-69.317,77.683,77.683) ENVELOPE(-68.521,-68.521,77.598,77.598) |
geographic |
Arctic Greenland Bowdoin Bowdoin Fjord |
geographic_facet |
Arctic Greenland Bowdoin Bowdoin Fjord |
genre |
Arctic glacier Greenland Phytoplankton |
genre_facet |
Arctic glacier Greenland Phytoplankton |
op_relation |
http://hdl.handle.net/2115/79982 Global Biogeochemical Cycles, 34(10): e2020GB006567 http://dx.doi.org/10.1029/2020GB006567 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2020GB006567 |
container_title |
Global Biogeochemical Cycles |
container_volume |
34 |
container_issue |
10 |
_version_ |
1766343507540180992 |