Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation
The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of key nutrients during winter months? Here we reveal, with silicon isotopes (δ30Si), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena Ri...
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ftunivlouvain:oai:dial.uclouvain.be:boreal:288308 2024-09-15T17:53:48+00:00 Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation Opfergelt, Sophie IBIS2024 UCL - SST/ELI/ELIE - Environmental Sciences 2024 http://hdl.handle.net/2078.1/288308 eng eng info:eu-repo/grantAgreement/ERC/H2020/WeThaw boreal:288308 http://hdl.handle.net/2078.1/288308 info:eu-repo/semantics/openAccess info:eu-repo/semantics/conferenceObject 2024 ftunivlouvain 2024-06-26T00:11:19Z The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of key nutrients during winter months? Here we reveal, with silicon isotopes (δ30Si), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena River catchment, conditions are met for frazil ice accumulation creating microzones. These are conducive for lengthened reaction time for biogeochemical processes under ice. The heavier δ30Si values (3.5 ± 0.5 ‰) in river water reflect that 39 ± 11% of the Lena River discharge went through these microzones. This can be explained by the supersaturation and precipitation of amorphous silica preferentially incorporating the lighter silicon isotopes, leaving the water isotopically heavier. Amorphous silica precipitation concomitant to an increase in ammonium concentration and changes in dissolved organic carbon aromaticity in Lena River water support microbially mediated processing of key nutrients (carbon, nitrogen) in these microzones. In a warming scenario considering shorter ice-covered periods, decreasing winter microbial processes in large Arctic rivers will decrease nitrogen supply to the Arctic Ocean, a key limiting nutrient. Conference Object Arctic Ocean lena river DIAL@UCLouvain (Université catholique de Louvain) |
institution |
Open Polar |
collection |
DIAL@UCLouvain (Université catholique de Louvain) |
op_collection_id |
ftunivlouvain |
language |
English |
description |
The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of key nutrients during winter months? Here we reveal, with silicon isotopes (δ30Si), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena River catchment, conditions are met for frazil ice accumulation creating microzones. These are conducive for lengthened reaction time for biogeochemical processes under ice. The heavier δ30Si values (3.5 ± 0.5 ‰) in river water reflect that 39 ± 11% of the Lena River discharge went through these microzones. This can be explained by the supersaturation and precipitation of amorphous silica preferentially incorporating the lighter silicon isotopes, leaving the water isotopically heavier. Amorphous silica precipitation concomitant to an increase in ammonium concentration and changes in dissolved organic carbon aromaticity in Lena River water support microbially mediated processing of key nutrients (carbon, nitrogen) in these microzones. In a warming scenario considering shorter ice-covered periods, decreasing winter microbial processes in large Arctic rivers will decrease nitrogen supply to the Arctic Ocean, a key limiting nutrient. |
author2 |
UCL - SST/ELI/ELIE - Environmental Sciences |
format |
Conference Object |
author |
Opfergelt, Sophie IBIS2024 |
spellingShingle |
Opfergelt, Sophie IBIS2024 Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
author_facet |
Opfergelt, Sophie IBIS2024 |
author_sort |
Opfergelt, Sophie |
title |
Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
title_short |
Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
title_full |
Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
title_fullStr |
Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
title_full_unstemmed |
Tracing changes in winter biogeochemical processes in Arctic rivers with amorphous silica precipitation |
title_sort |
tracing changes in winter biogeochemical processes in arctic rivers with amorphous silica precipitation |
publishDate |
2024 |
url |
http://hdl.handle.net/2078.1/288308 |
genre |
Arctic Ocean lena river |
genre_facet |
Arctic Ocean lena river |
op_relation |
info:eu-repo/grantAgreement/ERC/H2020/WeThaw boreal:288308 http://hdl.handle.net/2078.1/288308 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1810429859393961984 |