Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord
Global warming accelerates melting of glaciers and increases the supply of meltwater and associated inorganic particles, nutrients, and organic matter to adjacent coastal seas, but the ecosystem impact is poorly resolved and quantified. When meltwater is delivered by glacial rivers, the potential im...
Published in: | Proceedings of the National Academy of Sciences |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2022
|
Subjects: | |
Online Access: | https://orbit.dtu.dk/en/publications/fca4a951-fbe4-4ea5-ba15-6df49723760a https://doi.org/10.1073/pnas.2207024119 https://backend.orbit.dtu.dk/ws/files/300273185/pnas.2207024119.pdf |
id |
ftdtupubl:oai:pure.atira.dk:publications/fca4a951-fbe4-4ea5-ba15-6df49723760a |
---|---|
record_format |
openpolar |
spelling |
ftdtupubl:oai:pure.atira.dk:publications/fca4a951-fbe4-4ea5-ba15-6df49723760a 2024-06-23T07:50:42+00:00 Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord Sejr, Mikael K. Bruhn, Annette Dalsgaard, Tage Juul-Pedersen, Thomas Stedmon, Colin A. Blicher, Martin Meire, Lorenz Mankoff, Kenneth D. Thyrring, Jakob 2022 application/pdf https://orbit.dtu.dk/en/publications/fca4a951-fbe4-4ea5-ba15-6df49723760a https://doi.org/10.1073/pnas.2207024119 https://backend.orbit.dtu.dk/ws/files/300273185/pnas.2207024119.pdf eng eng https://orbit.dtu.dk/en/publications/fca4a951-fbe4-4ea5-ba15-6df49723760a info:eu-repo/semantics/openAccess Sejr , M K , Bruhn , A , Dalsgaard , T , Juul-Pedersen , T , Stedmon , C A , Blicher , M , Meire , L , Mankoff , K D & Thyrring , J 2022 , ' Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord ' , Proceedings of the National Academy of Sciences of the United States of America , vol. 119 , no. 52 , e2207024119 . https://doi.org/10.1073/pnas.2207024119 Coastal ecology Greenland Primary production Respiration CO2 /dk/atira/pure/sustainabledevelopmentgoals/life_on_land name=SDG 15 - Life on Land article 2022 ftdtupubl https://doi.org/10.1073/pnas.2207024119 2024-06-11T15:14:22Z Global warming accelerates melting of glaciers and increases the supply of meltwater and associated inorganic particles, nutrients, and organic matter to adjacent coastal seas, but the ecosystem impact is poorly resolved and quantified. When meltwater is delivered by glacial rivers, the potential impact could be a reduction in light and nutrient availability for primary producers while supplying allochthonous carbon for heterotrophic processes, thereby tipping the net community metabolism toward heterotrophy. To test this hypothesis, we determined physical and biogeochemical parameters along a 110-km fjord transect in NE Greenland fjord, impacted by glacial meltwater from the Greenland Ice Sheet. The meltwater is delivered from glacier-fed river outlets in the inner parts of the fjord, creating a gradient in salinity and turbidity. The planktonic primary production was low, 20-45 mg C m -2 d -1 , in the more turbid inner half of the fjord, increasing 10-fold to around 350 mg C m -2 d -1 in the shelf waters outside the fjord. Plankton community metabolism was measured at three stations, which displayed a transition from net heterotrophy in the inner fjord to net autotrophy in the coastal shelf waters. Respiration was significantly correlated to turbidity, with a 10-fold increase in the inner turbid part of the fjord. We estimated the changes in meltwater input and sea ice coverage in the area for the last 60 y. The long-term trend and the observed effects demonstrated the importance of freshwater runoff as a key driver of coastal ecosystem change in the Arctic with potential negative consequences for coastal productivity. Article in Journal/Newspaper Arctic glacier Global warming Greenland Ice Sheet Sea ice Technical University of Denmark: DTU Orbit Arctic Greenland Proceedings of the National Academy of Sciences 119 52 |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
topic |
Coastal ecology Greenland Primary production Respiration CO2 /dk/atira/pure/sustainabledevelopmentgoals/life_on_land name=SDG 15 - Life on Land |
spellingShingle |
Coastal ecology Greenland Primary production Respiration CO2 /dk/atira/pure/sustainabledevelopmentgoals/life_on_land name=SDG 15 - Life on Land Sejr, Mikael K. Bruhn, Annette Dalsgaard, Tage Juul-Pedersen, Thomas Stedmon, Colin A. Blicher, Martin Meire, Lorenz Mankoff, Kenneth D. Thyrring, Jakob Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
topic_facet |
Coastal ecology Greenland Primary production Respiration CO2 /dk/atira/pure/sustainabledevelopmentgoals/life_on_land name=SDG 15 - Life on Land |
description |
Global warming accelerates melting of glaciers and increases the supply of meltwater and associated inorganic particles, nutrients, and organic matter to adjacent coastal seas, but the ecosystem impact is poorly resolved and quantified. When meltwater is delivered by glacial rivers, the potential impact could be a reduction in light and nutrient availability for primary producers while supplying allochthonous carbon for heterotrophic processes, thereby tipping the net community metabolism toward heterotrophy. To test this hypothesis, we determined physical and biogeochemical parameters along a 110-km fjord transect in NE Greenland fjord, impacted by glacial meltwater from the Greenland Ice Sheet. The meltwater is delivered from glacier-fed river outlets in the inner parts of the fjord, creating a gradient in salinity and turbidity. The planktonic primary production was low, 20-45 mg C m -2 d -1 , in the more turbid inner half of the fjord, increasing 10-fold to around 350 mg C m -2 d -1 in the shelf waters outside the fjord. Plankton community metabolism was measured at three stations, which displayed a transition from net heterotrophy in the inner fjord to net autotrophy in the coastal shelf waters. Respiration was significantly correlated to turbidity, with a 10-fold increase in the inner turbid part of the fjord. We estimated the changes in meltwater input and sea ice coverage in the area for the last 60 y. The long-term trend and the observed effects demonstrated the importance of freshwater runoff as a key driver of coastal ecosystem change in the Arctic with potential negative consequences for coastal productivity. |
format |
Article in Journal/Newspaper |
author |
Sejr, Mikael K. Bruhn, Annette Dalsgaard, Tage Juul-Pedersen, Thomas Stedmon, Colin A. Blicher, Martin Meire, Lorenz Mankoff, Kenneth D. Thyrring, Jakob |
author_facet |
Sejr, Mikael K. Bruhn, Annette Dalsgaard, Tage Juul-Pedersen, Thomas Stedmon, Colin A. Blicher, Martin Meire, Lorenz Mankoff, Kenneth D. Thyrring, Jakob |
author_sort |
Sejr, Mikael K. |
title |
Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
title_short |
Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
title_full |
Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
title_fullStr |
Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
title_full_unstemmed |
Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord |
title_sort |
glacial meltwater determines the balance between autotrophic and heterotrophic processes in a greenland fjord |
publishDate |
2022 |
url |
https://orbit.dtu.dk/en/publications/fca4a951-fbe4-4ea5-ba15-6df49723760a https://doi.org/10.1073/pnas.2207024119 https://backend.orbit.dtu.dk/ws/files/300273185/pnas.2207024119.pdf |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic glacier Global warming Greenland Ice Sheet Sea ice |
genre_facet |
Arctic glacier Global warming Greenland Ice Sheet Sea ice |
op_source |
Sejr , M K , Bruhn , A , Dalsgaard , T , Juul-Pedersen , T , Stedmon , C A , Blicher , M , Meire , L , Mankoff , K D & Thyrring , J 2022 , ' Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord ' , Proceedings of the National Academy of Sciences of the United States of America , vol. 119 , no. 52 , e2207024119 . https://doi.org/10.1073/pnas.2207024119 |
op_relation |
https://orbit.dtu.dk/en/publications/fca4a951-fbe4-4ea5-ba15-6df49723760a |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1073/pnas.2207024119 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
119 |
container_issue |
52 |
_version_ |
1802641617782308864 |