Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean
Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainl...
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/54141 2023-05-15T18:28:05+02:00 Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean Yamashita, Youhei Nosaka, Yuichi Suzuki, Koji Ogawa, Hiroshi Takahashi, Kazutaka Saito, Hiroaki http://hdl.handle.net/2115/54141 https://doi.org/10.5194/bg-10-7207-2013 eng eng Copernicus Gesellschaft mbh http://www.biogeosciences.net/10/7207/2013/bg-10-7207-2013.html http://hdl.handle.net/2115/54141 Biogeosciences, 10(11): 7207-7217 http://dx.doi.org/10.5194/bg-10-7207-2013 © Author(s) 2013. This work is distributedunder the Creative Commons Attribution 3.0 License. http://creativecommons.org/licenses/by/3.0/ CC-BY 452 article fthokunivhus https://doi.org/10.5194/bg-10-7207-2013 2022-11-18T01:02:57Z Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainly controlled by in situ production and photobleaching. However, factors controlling the spectral parameters of CDOM in the UV region, i.e., spectral slope of CDOM determined at 275-295 nm (S275-295) and the ratio of two spectral slope parameters (S-R); the ratio of S275-295 to S350-400, have not been well documented. To evaluate the factor controlling the spectral characteristics of CDOM in the UV region in the open ocean, we determined the quantitative and qualitative characteristics of CDOM in the subarctic and subtropical surface waters (5-300 m) of the western North Pacific. Absorption coefficients at 320 nm in the subarctic region were higher than those in the subtropical region throughout surface waters, suggesting that magnitudes of photobleaching were different between the two regions. The values of S275-295 and SR were also higher in the subtropical region than the subarctic region. The dark microbial incubation showed biodegradation of DOM little affected S275-295, but slightly decreased SR. On the other hand, increases in S275-295 and relative stableness of SR were observed during photo-irradiation incubations respectively. These experimental results indicated that photobleaching of CDOM mainly induced qualitative differences in CDOM at UV region between the subarctic and subtropical surface waters. The results of this study imply that S275-295 can be used as a tracer of photochemical history of CDOM in the open ocean. Article in Journal/Newspaper Subarctic Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Pacific Biogeosciences 10 11 7207 7217 |
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Open Polar |
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Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
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fthokunivhus |
language |
English |
topic |
452 |
spellingShingle |
452 Yamashita, Youhei Nosaka, Yuichi Suzuki, Koji Ogawa, Hiroshi Takahashi, Kazutaka Saito, Hiroaki Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
topic_facet |
452 |
description |
Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainly controlled by in situ production and photobleaching. However, factors controlling the spectral parameters of CDOM in the UV region, i.e., spectral slope of CDOM determined at 275-295 nm (S275-295) and the ratio of two spectral slope parameters (S-R); the ratio of S275-295 to S350-400, have not been well documented. To evaluate the factor controlling the spectral characteristics of CDOM in the UV region in the open ocean, we determined the quantitative and qualitative characteristics of CDOM in the subarctic and subtropical surface waters (5-300 m) of the western North Pacific. Absorption coefficients at 320 nm in the subarctic region were higher than those in the subtropical region throughout surface waters, suggesting that magnitudes of photobleaching were different between the two regions. The values of S275-295 and SR were also higher in the subtropical region than the subarctic region. The dark microbial incubation showed biodegradation of DOM little affected S275-295, but slightly decreased SR. On the other hand, increases in S275-295 and relative stableness of SR were observed during photo-irradiation incubations respectively. These experimental results indicated that photobleaching of CDOM mainly induced qualitative differences in CDOM at UV region between the subarctic and subtropical surface waters. The results of this study imply that S275-295 can be used as a tracer of photochemical history of CDOM in the open ocean. |
format |
Article in Journal/Newspaper |
author |
Yamashita, Youhei Nosaka, Yuichi Suzuki, Koji Ogawa, Hiroshi Takahashi, Kazutaka Saito, Hiroaki |
author_facet |
Yamashita, Youhei Nosaka, Yuichi Suzuki, Koji Ogawa, Hiroshi Takahashi, Kazutaka Saito, Hiroaki |
author_sort |
Yamashita, Youhei |
title |
Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
title_short |
Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
title_full |
Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
title_fullStr |
Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
title_full_unstemmed |
Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
title_sort |
photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean |
publisher |
Copernicus Gesellschaft mbh |
url |
http://hdl.handle.net/2115/54141 https://doi.org/10.5194/bg-10-7207-2013 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Subarctic |
genre_facet |
Subarctic |
op_relation |
http://www.biogeosciences.net/10/7207/2013/bg-10-7207-2013.html http://hdl.handle.net/2115/54141 Biogeosciences, 10(11): 7207-7217 http://dx.doi.org/10.5194/bg-10-7207-2013 |
op_rights |
© Author(s) 2013. This work is distributedunder the Creative Commons Attribution 3.0 License. http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/bg-10-7207-2013 |
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Biogeosciences |
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10 |
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11 |
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7207 |
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7217 |
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1766210425624461312 |