Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea
The interpretation of decline in dissolved oxygen (DO) in the oxygenated bottom water of the Ulleung Basin (UB), southwest of the East/Japan Sea has been challenging because of the integrated influence of various DO-consuming processes. Therefore, the stable oxygen isotopic fractionation of DO was i...
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| Format: | Article |
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Frontiers Media S.A.
2024-01-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1276028/full |
| _version_ | 1797357707740577792 |
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| author | Yeseul Kim Dong-Jin Kang Dong-Jin Kang |
| author_facet | Yeseul Kim Dong-Jin Kang Dong-Jin Kang |
| author_sort | Yeseul Kim |
| collection | DOAJ |
| description | The interpretation of decline in dissolved oxygen (DO) in the oxygenated bottom water of the Ulleung Basin (UB), southwest of the East/Japan Sea has been challenging because of the integrated influence of various DO-consuming processes. Therefore, the stable oxygen isotopic fractionation of DO was investigated to enhance our understanding of the distinct DO consumption observed in the bottom layers of the center of the UB. We explored the relationship between DO and its oxygen isotope composition (δ18ODO) using data collected at a station located in the center of the UB in 2020, 2021, and 2022. An unforeseen decrease in δ18ODO in the bottom layer (> 1800 m) where DO was depleted was discovered. The overall DO consumption in the mesopelagic water layer (300–1000 m), primarily attributed to water column respiration, exhibited an isotopic fractionation factor (α) with 0.985 ± 0.001 in the δ18ODO/[O2] relationship. The consumptive isotope fractionation factor in the bottom waters near the sediments (approximately 2146 m) showed a value slightly higher (0.988 ± 0.002) than that in the mesopelagic water layer. This isotopic signature is likely due to a smaller fractionation in the bottom waters relative to the mesopelagic water. The isotopic evidence suggests the involvement of mineral oxidation associated with excess dissolved Mn and Fe in the bottom waters because mineral oxidation exhibits a smaller fractionation effect than respiration. Our study demonstrates that DO depletion results from multiple consumption processes, including respiration, mineral oxidation, and diffusive transport, and the isotopic behavior provides evidence that mineral oxidation significantly influences DO consumption. |
| first_indexed | 2024-03-08T14:48:02Z |
| format | Article |
| id | doaj.art-7705830944594197851ea9d54824756b |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-03-08T14:48:02Z |
| publishDate | 2024-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-7705830944594197851ea9d54824756b2024-01-11T05:16:24ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-01-011010.3389/fmars.2023.12760281276028Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan SeaYeseul Kim0Dong-Jin Kang1Dong-Jin Kang2Marine Environmental Research Department, Korea Institute of Ocean Science and Technology (KIOST), Busan, Republic of KoreaKorea Institute of Ocean Science and Technology (KIOST) School and Academic Programs Division, Korea Institute of Ocean Science and Technology (KIOST), Busan, Republic of KoreaDepartment of Ocean Science, University of Science and Technology (UST), Daejeon, Republic of KoreaThe interpretation of decline in dissolved oxygen (DO) in the oxygenated bottom water of the Ulleung Basin (UB), southwest of the East/Japan Sea has been challenging because of the integrated influence of various DO-consuming processes. Therefore, the stable oxygen isotopic fractionation of DO was investigated to enhance our understanding of the distinct DO consumption observed in the bottom layers of the center of the UB. We explored the relationship between DO and its oxygen isotope composition (δ18ODO) using data collected at a station located in the center of the UB in 2020, 2021, and 2022. An unforeseen decrease in δ18ODO in the bottom layer (> 1800 m) where DO was depleted was discovered. The overall DO consumption in the mesopelagic water layer (300–1000 m), primarily attributed to water column respiration, exhibited an isotopic fractionation factor (α) with 0.985 ± 0.001 in the δ18ODO/[O2] relationship. The consumptive isotope fractionation factor in the bottom waters near the sediments (approximately 2146 m) showed a value slightly higher (0.988 ± 0.002) than that in the mesopelagic water layer. This isotopic signature is likely due to a smaller fractionation in the bottom waters relative to the mesopelagic water. The isotopic evidence suggests the involvement of mineral oxidation associated with excess dissolved Mn and Fe in the bottom waters because mineral oxidation exhibits a smaller fractionation effect than respiration. Our study demonstrates that DO depletion results from multiple consumption processes, including respiration, mineral oxidation, and diffusive transport, and the isotopic behavior provides evidence that mineral oxidation significantly influences DO consumption.https://www.frontiersin.org/articles/10.3389/fmars.2023.1276028/fulldissolved oxygenoxygen depletionmultiple consumption factorsoxygen isotopic compositionUlleung BasinEast/Japan Sea |
| spellingShingle | Yeseul Kim Dong-Jin Kang Dong-Jin Kang Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea Frontiers in Marine Science dissolved oxygen oxygen depletion multiple consumption factors oxygen isotopic composition Ulleung Basin East/Japan Sea |
| title | Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea |
| title_full | Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea |
| title_fullStr | Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea |
| title_full_unstemmed | Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea |
| title_short | Oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the Ulleung Basin, East/Japan Sea |
| title_sort | oxygen isotopic fractionation during dissolved oxygen consumption in the bottom layer of the ulleung basin east japan sea |
| topic | dissolved oxygen oxygen depletion multiple consumption factors oxygen isotopic composition Ulleung Basin East/Japan Sea |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1276028/full |
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