Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing
River water is the main source of dissolved organic carbon (DOC) in the Arctic Ocean. DOC plays an important role in the Arctic carbon cycle, and its export from land to sea is expected to increase as ongoing climate change accelerates permafrost thaw. However, transport pathways and transformation...
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Freie Universität Berlin
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ftdatacite:10.17169/refubium-3891 2023-05-15T14:59:45+02:00 Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing Juhls, Bennet Overduin, Pier Paul Hölemann, Jens Hieronymi, Martin Matsuoka, Atsushi Heim, Birgit Fischer, Jürgen 2019 https://dx.doi.org/10.17169/refubium-3891 https://refubium.fu-berlin.de/handle/fub188/25186 unknown Freie Universität Berlin https://doi.org/10.5194/bg-16-2693-2019 https://dx.doi.org/10.5194/bg-16-2693-2019 https://doi.org/10.5194/bg-16-2693-2019 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 CC-BY Laptev Sea ocean colour remote sensing dissolved organic matter 500 Naturwissenschaften und Mathematik550 Geowissenschaften, Geologie550 Geowissenschaften Text article-journal Wissenschaftlicher Artikel ScholarlyArticle 2019 ftdatacite https://doi.org/10.17169/refubium-3891 https://doi.org/10.5194/bg-16-2693-2019 2021-11-05T12:55:41Z River water is the main source of dissolved organic carbon (DOC) in the Arctic Ocean. DOC plays an important role in the Arctic carbon cycle, and its export from land to sea is expected to increase as ongoing climate change accelerates permafrost thaw. However, transport pathways and transformation of DOC in the land-to-ocean transition are mostly unknown. We collected DOC and aCDOM(λ) samples from 11 expeditions to river, coastal and offshore waters and present a new DOC–aCDOM(λ) model for the fluvial–marine transition zone in the Laptev Sea. The aCDOM(λ) characteristics revealed that the dissolved organic matter (DOM) in samples of this dataset are primarily of terrigenous origin. Observed changes in aCDOM(443) and its spectral slopes indicate that DOM is modified by microbial and photo-degradation. Ocean colour remote sensing (OCRS) provides the absorption coefficient of coloured dissolved organic matter (aCDOM(λ)sat) at λ=440 or 443 nm, which can be used to estimate DOC concentration at high temporal and spatial resolution over large regions. We tested the statistical performance of five OCRS algorithms and evaluated the plausibility of the spatial distribution of derived aCDOM(λ)sat. The OLCI (Sentinel-3 Ocean and Land Colour Instrument) neural network swarm (ONNS) algorithm showed the best performance compared to in situ aCDOM(440) (r2=0.72). Additionally, we found ONNS-derived aCDOM(440), in contrast to other algorithms, to be partly independent of sediment concentration, making ONNS the most suitable aCDOM(λ)sat algorithm for the Laptev Sea region. The DOC–aCDOM(λ) model was applied to ONNS-derived aCDOM(440), and retrieved DOC concentration maps showed moderate agreement to in situ data (r2=0.53). The in situ and satellite-retrieved data were offset by up to several days, which may partly explain the weak correlation for this dynamic region. Satellite-derived surface water DOC concentration maps from Medium Resolution Imaging Spectrometer (MERIS) satellite data demonstrate rapid removal of DOC within short time periods in coastal waters of the Laptev Sea, which is likely caused by physical mixing and different types of degradation processes. Using samples from all occurring water types leads to a more robust DOC–aCDOM(λ) model for the retrievals of DOC in Arctic shelf and river waters. Text Arctic Arctic Ocean Climate change laptev Laptev Sea permafrost DataCite Metadata Store (German National Library of Science and Technology) Arctic Arctic Ocean Laptev Sea |
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DataCite Metadata Store (German National Library of Science and Technology) |
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language |
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topic |
Laptev Sea ocean colour remote sensing dissolved organic matter 500 Naturwissenschaften und Mathematik550 Geowissenschaften, Geologie550 Geowissenschaften |
spellingShingle |
Laptev Sea ocean colour remote sensing dissolved organic matter 500 Naturwissenschaften und Mathematik550 Geowissenschaften, Geologie550 Geowissenschaften Juhls, Bennet Overduin, Pier Paul Hölemann, Jens Hieronymi, Martin Matsuoka, Atsushi Heim, Birgit Fischer, Jürgen Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
topic_facet |
Laptev Sea ocean colour remote sensing dissolved organic matter 500 Naturwissenschaften und Mathematik550 Geowissenschaften, Geologie550 Geowissenschaften |
description |
River water is the main source of dissolved organic carbon (DOC) in the Arctic Ocean. DOC plays an important role in the Arctic carbon cycle, and its export from land to sea is expected to increase as ongoing climate change accelerates permafrost thaw. However, transport pathways and transformation of DOC in the land-to-ocean transition are mostly unknown. We collected DOC and aCDOM(λ) samples from 11 expeditions to river, coastal and offshore waters and present a new DOC–aCDOM(λ) model for the fluvial–marine transition zone in the Laptev Sea. The aCDOM(λ) characteristics revealed that the dissolved organic matter (DOM) in samples of this dataset are primarily of terrigenous origin. Observed changes in aCDOM(443) and its spectral slopes indicate that DOM is modified by microbial and photo-degradation. Ocean colour remote sensing (OCRS) provides the absorption coefficient of coloured dissolved organic matter (aCDOM(λ)sat) at λ=440 or 443 nm, which can be used to estimate DOC concentration at high temporal and spatial resolution over large regions. We tested the statistical performance of five OCRS algorithms and evaluated the plausibility of the spatial distribution of derived aCDOM(λ)sat. The OLCI (Sentinel-3 Ocean and Land Colour Instrument) neural network swarm (ONNS) algorithm showed the best performance compared to in situ aCDOM(440) (r2=0.72). Additionally, we found ONNS-derived aCDOM(440), in contrast to other algorithms, to be partly independent of sediment concentration, making ONNS the most suitable aCDOM(λ)sat algorithm for the Laptev Sea region. The DOC–aCDOM(λ) model was applied to ONNS-derived aCDOM(440), and retrieved DOC concentration maps showed moderate agreement to in situ data (r2=0.53). The in situ and satellite-retrieved data were offset by up to several days, which may partly explain the weak correlation for this dynamic region. Satellite-derived surface water DOC concentration maps from Medium Resolution Imaging Spectrometer (MERIS) satellite data demonstrate rapid removal of DOC within short time periods in coastal waters of the Laptev Sea, which is likely caused by physical mixing and different types of degradation processes. Using samples from all occurring water types leads to a more robust DOC–aCDOM(λ) model for the retrievals of DOC in Arctic shelf and river waters. |
format |
Text |
author |
Juhls, Bennet Overduin, Pier Paul Hölemann, Jens Hieronymi, Martin Matsuoka, Atsushi Heim, Birgit Fischer, Jürgen |
author_facet |
Juhls, Bennet Overduin, Pier Paul Hölemann, Jens Hieronymi, Martin Matsuoka, Atsushi Heim, Birgit Fischer, Jürgen |
author_sort |
Juhls, Bennet |
title |
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
title_short |
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
title_full |
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
title_fullStr |
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
title_full_unstemmed |
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing |
title_sort |
dissolved organic matter at the fluvial–marine transition in the laptev sea using in situ data and ocean colour remote sensing |
publisher |
Freie Universität Berlin |
publishDate |
2019 |
url |
https://dx.doi.org/10.17169/refubium-3891 https://refubium.fu-berlin.de/handle/fub188/25186 |
geographic |
Arctic Arctic Ocean Laptev Sea |
geographic_facet |
Arctic Arctic Ocean Laptev Sea |
genre |
Arctic Arctic Ocean Climate change laptev Laptev Sea permafrost |
genre_facet |
Arctic Arctic Ocean Climate change laptev Laptev Sea permafrost |
op_relation |
https://doi.org/10.5194/bg-16-2693-2019 https://dx.doi.org/10.5194/bg-16-2693-2019 https://doi.org/10.5194/bg-16-2693-2019 |
op_rights |
Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.17169/refubium-3891 https://doi.org/10.5194/bg-16-2693-2019 |
_version_ |
1766331871741870080 |