Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun
Changes in vertical and spatial distributions of zooplankton and small pelagic fish impact the biological carbon pump and the distribution of larger piscivorous fish and marine mammal species. However, their distribution and abundance remain poorly documented at high latitudes because of the difficu...
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ftimr:oai:imr.brage.unit.no:11250/2759472 2023-05-15T14:48:20+02:00 Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun Priou, Pierre Nikolopoulos, Anna Flores, Hauke Gradinger, Rolf Kunisch, Eirin Katlein, Christian Castellani, Giulia Linders, Torsten Theodor Berge, Jørgen Fisher, Jonathan A.D. Geoffroy, Maxime 2021 application/pdf https://hdl.handle.net/11250/2759472 https://doi.org/10.1016/j.pocean.2021.102611 eng eng Progress in Oceanography. 2021, 196 . urn:issn:0079-6611 https://hdl.handle.net/11250/2759472 https://doi.org/10.1016/j.pocean.2021.102611 cristin:1914388 11 196 Progress in Oceanography Peer reviewed Journal article 2021 ftimr https://doi.org/10.1016/j.pocean.2021.102611 2021-09-23T20:16:12Z Changes in vertical and spatial distributions of zooplankton and small pelagic fish impact the biological carbon pump and the distribution of larger piscivorous fish and marine mammal species. However, their distribution and abundance remain poorly documented at high latitudes because of the difficulties inherent to sampling relatively fast-moving organisms in ice-covered waters. This study documents the under-ice distribution of epipelagic and mesopelagic organisms at the Arctic-Atlantic gateway in spring, during the midnight sun period, using ice-tethered and ship-based echosounders. An epipelagic surface scattering layer composed of copepods consistently occupied the top 60 m and was associated with cold polar surface water (mean temperature of −1.5 °C). A mesopelagic deep scattering layer (DSL), partly composed of fish, persisted between 280 m and 600 m and was associated with modified Atlantic water. Backscattering strength within the DSL was higher than previously reported in the Arctic and north Atlantic, and increased by two orders of magnitude over the continental slope where one of the Atlantic water pathways enters the Arctic Ocean. Mesopelagic organisms did not perform diel vertical migrations. The consistent segregation between copepods at the surface and their predators at mesopelagic depths suggests limited predator–prey interactions during the midnight sun period, even under the ice cover. Predation on copepods by mesopelagic organisms, including fish, could thus be limited to very pulsed events during the seasonal vertical migration of copepods to and from overwintering depths. This suggests that the arctic mesopelagic food web may be decoupled from secondary production in the epipelagic layer throughout most of the year. publishedVersion Article in Journal/Newspaper Arctic Arctic Ocean North Atlantic Zooplankton Copepods ice covered waters midnight sun Institute for Marine Research: Brage IMR Arctic Arctic Ocean Progress in Oceanography 196 102611 |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
description |
Changes in vertical and spatial distributions of zooplankton and small pelagic fish impact the biological carbon pump and the distribution of larger piscivorous fish and marine mammal species. However, their distribution and abundance remain poorly documented at high latitudes because of the difficulties inherent to sampling relatively fast-moving organisms in ice-covered waters. This study documents the under-ice distribution of epipelagic and mesopelagic organisms at the Arctic-Atlantic gateway in spring, during the midnight sun period, using ice-tethered and ship-based echosounders. An epipelagic surface scattering layer composed of copepods consistently occupied the top 60 m and was associated with cold polar surface water (mean temperature of −1.5 °C). A mesopelagic deep scattering layer (DSL), partly composed of fish, persisted between 280 m and 600 m and was associated with modified Atlantic water. Backscattering strength within the DSL was higher than previously reported in the Arctic and north Atlantic, and increased by two orders of magnitude over the continental slope where one of the Atlantic water pathways enters the Arctic Ocean. Mesopelagic organisms did not perform diel vertical migrations. The consistent segregation between copepods at the surface and their predators at mesopelagic depths suggests limited predator–prey interactions during the midnight sun period, even under the ice cover. Predation on copepods by mesopelagic organisms, including fish, could thus be limited to very pulsed events during the seasonal vertical migration of copepods to and from overwintering depths. This suggests that the arctic mesopelagic food web may be decoupled from secondary production in the epipelagic layer throughout most of the year. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Priou, Pierre Nikolopoulos, Anna Flores, Hauke Gradinger, Rolf Kunisch, Eirin Katlein, Christian Castellani, Giulia Linders, Torsten Theodor Berge, Jørgen Fisher, Jonathan A.D. Geoffroy, Maxime |
spellingShingle |
Priou, Pierre Nikolopoulos, Anna Flores, Hauke Gradinger, Rolf Kunisch, Eirin Katlein, Christian Castellani, Giulia Linders, Torsten Theodor Berge, Jørgen Fisher, Jonathan A.D. Geoffroy, Maxime Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
author_facet |
Priou, Pierre Nikolopoulos, Anna Flores, Hauke Gradinger, Rolf Kunisch, Eirin Katlein, Christian Castellani, Giulia Linders, Torsten Theodor Berge, Jørgen Fisher, Jonathan A.D. Geoffroy, Maxime |
author_sort |
Priou, Pierre |
title |
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
title_short |
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
title_full |
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
title_fullStr |
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
title_full_unstemmed |
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun |
title_sort |
dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the arctic-atlantic gateway during the midnight sun |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2759472 https://doi.org/10.1016/j.pocean.2021.102611 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean North Atlantic Zooplankton Copepods ice covered waters midnight sun |
genre_facet |
Arctic Arctic Ocean North Atlantic Zooplankton Copepods ice covered waters midnight sun |
op_source |
11 196 Progress in Oceanography |
op_relation |
Progress in Oceanography. 2021, 196 . urn:issn:0079-6611 https://hdl.handle.net/11250/2759472 https://doi.org/10.1016/j.pocean.2021.102611 cristin:1914388 |
op_doi |
https://doi.org/10.1016/j.pocean.2021.102611 |
container_title |
Progress in Oceanography |
container_volume |
196 |
container_start_page |
102611 |
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1766319410757238784 |