Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions
Upwelling and downwelling spectral (320–920 nm) distributions and photosynthetic active radiation (PAR) intensities were measured below a first-year land-fast sea ice in a western Greenland fjord with and without a snow cover. Time-series of surface upwelling PAR, downwelling PAR, and under-ice PAR...
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2021
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ftunivutrecht:oai:dspace.library.uu.nl:1874/413746 2023-12-10T09:49:10+01:00 Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions Lund-Hansen, Lars Chresten Bjerg-Nielsen, Michael Stratmann, Tanja Hawes, Ian Sorrell, Brian K. Geochemistry Bio-, hydro-, and environmental geochemistry 2021-08 application/pdf https://dspace.library.uu.nl/handle/1874/413746 eng eng https://dspace.library.uu.nl/handle/1874/413746 info:eu-repo/semantics/OpenAccess 2021 ftunivutrecht 2023-11-15T23:19:40Z Upwelling and downwelling spectral (320–920 nm) distributions and photosynthetic active radiation (PAR) intensities were measured below a first-year land-fast sea ice in a western Greenland fjord with and without a snow cover. Time-series of surface upwelling PAR, downwelling PAR, and under-ice PAR were also obtained. Spectral distributions of upwelling and downwelling irradiances were similar except for reduced intensities in the UV, the red, and NIR parts of the spectrum when the ice was snow-covered. Upwelling PAR amounted to about 10% of downwelling intensities, giving 5.1 µmol photons m−2 s−1 at the bottom of the ice with a snow cover and 8.2 µmol photons m−2 s−1 without. PAR partitioning analyses showed that the upwelling was related to scattering by suspended particles in the water column. A snow melt increased under-ice daily maximum downwelling PAR from 50 to 180 µmol photons m−2 s−1 and overall under-ice PAR of 55 and 198 µmol photons m−2 s−1 with 10% upwelling. It is concluded that upwelling PAR below sea ice might be an important factor regarding sea ice algae photophysiology and performance with a 10% higher PAR; specifically when PAR > Ek the light saturation point of the sea ice algae. Other/Unknown Material Greenland ice algae Sea ice Utrecht University Repository Greenland |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
description |
Upwelling and downwelling spectral (320–920 nm) distributions and photosynthetic active radiation (PAR) intensities were measured below a first-year land-fast sea ice in a western Greenland fjord with and without a snow cover. Time-series of surface upwelling PAR, downwelling PAR, and under-ice PAR were also obtained. Spectral distributions of upwelling and downwelling irradiances were similar except for reduced intensities in the UV, the red, and NIR parts of the spectrum when the ice was snow-covered. Upwelling PAR amounted to about 10% of downwelling intensities, giving 5.1 µmol photons m−2 s−1 at the bottom of the ice with a snow cover and 8.2 µmol photons m−2 s−1 without. PAR partitioning analyses showed that the upwelling was related to scattering by suspended particles in the water column. A snow melt increased under-ice daily maximum downwelling PAR from 50 to 180 µmol photons m−2 s−1 and overall under-ice PAR of 55 and 198 µmol photons m−2 s−1 with 10% upwelling. It is concluded that upwelling PAR below sea ice might be an important factor regarding sea ice algae photophysiology and performance with a 10% higher PAR; specifically when PAR > Ek the light saturation point of the sea ice algae. |
author2 |
Geochemistry Bio-, hydro-, and environmental geochemistry |
author |
Lund-Hansen, Lars Chresten Bjerg-Nielsen, Michael Stratmann, Tanja Hawes, Ian Sorrell, Brian K. |
spellingShingle |
Lund-Hansen, Lars Chresten Bjerg-Nielsen, Michael Stratmann, Tanja Hawes, Ian Sorrell, Brian K. Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
author_facet |
Lund-Hansen, Lars Chresten Bjerg-Nielsen, Michael Stratmann, Tanja Hawes, Ian Sorrell, Brian K. |
author_sort |
Lund-Hansen, Lars Chresten |
title |
Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
title_short |
Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
title_full |
Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
title_fullStr |
Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
title_full_unstemmed |
Upwelling Irradiance below Sea Ice—PAR Intensities and Spectral Distributions |
title_sort |
upwelling irradiance below sea ice—par intensities and spectral distributions |
publishDate |
2021 |
url |
https://dspace.library.uu.nl/handle/1874/413746 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice algae Sea ice |
genre_facet |
Greenland ice algae Sea ice |
op_relation |
https://dspace.library.uu.nl/handle/1874/413746 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1784893488803872768 |