Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana
The positive or negative effect of a decrease in dissolved O2 on the photophysiology of phytoplankton is determined by the duration of light exposure. To uncover the underlying mechanisms, the marine model diatom Thalassiosira pseudonana was cultured under three dissolved O2 levels (8.0 mg L-1, ambi...
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Frontiers Media S.A.
2025-02-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2025.1529163/full |
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| author | Bokun Chen Bokun Chen Hui Song Hui Song Ge Xu Hongli Ji Hongli Ji Xue Yang Xue Yang Gang Li |
| author_facet | Bokun Chen Bokun Chen Hui Song Hui Song Ge Xu Hongli Ji Hongli Ji Xue Yang Xue Yang Gang Li |
| author_sort | Bokun Chen |
| collection | DOAJ |
| description | The positive or negative effect of a decrease in dissolved O2 on the photophysiology of phytoplankton is determined by the duration of light exposure. To uncover the underlying mechanisms, the marine model diatom Thalassiosira pseudonana was cultured under three dissolved O2 levels (8.0 mg L-1, ambient O2; 4.0 mg L-1, low O2; and 1.3 mg L-1, hypoxia) to compare its growth, cell composition, and physiology between the light and dark periods. The results showed that the growth rate under ambient O2 was 0.60 ± 0.02 day-1, which was half of the growth rate during light period and 15-fold of the growth rate during dark period. Decreasing O2 increased the growth rate during light period but decreased it during dark period and decreased the cell pigment content in both the light and dark periods. In the light, low O2 increased cell carbon (C) content, while hypoxia decreased it, with the degree of increase and decrease being greater in the dark. Low O2 had no significant effect on cell nitrogen (N) content, but hypoxia decreased it. Low O2 had no significant effect on photosynthetic efficiency but decreased the dark respiration rate. In darkness, low O2 had no significant effect on cell C loss rate but decreased N loss rate, leading to an increase in the POC/PON ratio. In addition, hypoxia exacerbated cell mortality and sinking, suggesting that diatom-derived carbon burial may be accelerated due to marine deoxygenation in the future. |
| format | Article |
| id | doaj-art-4444742b36ba483c81570419dee6258d |
| institution | Kabale University |
| issn | 2296-7745 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Marine Science |
| spelling | doaj-art-4444742b36ba483c81570419dee6258d2025-02-06T05:21:44ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-02-011210.3389/fmars.2025.15291631529163Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonanaBokun Chen0Bokun Chen1Hui Song2Hui Song3Ge Xu4Hongli Ji5Hongli Ji6Xue Yang7Xue Yang8Gang Li9Institute of Marine Science and Technology, Shandong University, Qingdao, ChinaQingdao Key Laboratory of Ocean Carbon Sequestration and Negative Emission Technology, Shandong University, Qingdao, ChinaInstitute of Marine Science and Technology, Shandong University, Qingdao, ChinaQingdao Key Laboratory of Ocean Carbon Sequestration and Negative Emission Technology, Shandong University, Qingdao, ChinaMarine Environmental Monitoring Centre of Ningbo, East China Sea Bureau of Ministry of Natural Resources, Ningbo, ChinaInstitute of Marine Science and Technology, Shandong University, Qingdao, ChinaQingdao Key Laboratory of Ocean Carbon Sequestration and Negative Emission Technology, Shandong University, Qingdao, ChinaInstitute of Marine Science and Technology, Shandong University, Qingdao, ChinaQingdao Key Laboratory of Ocean Carbon Sequestration and Negative Emission Technology, Shandong University, Qingdao, ChinaDaya Bay Marine Biology Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, ChinaThe positive or negative effect of a decrease in dissolved O2 on the photophysiology of phytoplankton is determined by the duration of light exposure. To uncover the underlying mechanisms, the marine model diatom Thalassiosira pseudonana was cultured under three dissolved O2 levels (8.0 mg L-1, ambient O2; 4.0 mg L-1, low O2; and 1.3 mg L-1, hypoxia) to compare its growth, cell composition, and physiology between the light and dark periods. The results showed that the growth rate under ambient O2 was 0.60 ± 0.02 day-1, which was half of the growth rate during light period and 15-fold of the growth rate during dark period. Decreasing O2 increased the growth rate during light period but decreased it during dark period and decreased the cell pigment content in both the light and dark periods. In the light, low O2 increased cell carbon (C) content, while hypoxia decreased it, with the degree of increase and decrease being greater in the dark. Low O2 had no significant effect on cell nitrogen (N) content, but hypoxia decreased it. Low O2 had no significant effect on photosynthetic efficiency but decreased the dark respiration rate. In darkness, low O2 had no significant effect on cell C loss rate but decreased N loss rate, leading to an increase in the POC/PON ratio. In addition, hypoxia exacerbated cell mortality and sinking, suggesting that diatom-derived carbon burial may be accelerated due to marine deoxygenation in the future.https://www.frontiersin.org/articles/10.3389/fmars.2025.1529163/fulllowering O2light and darkdiatomcell compositionsinking rate |
| spellingShingle | Bokun Chen Bokun Chen Hui Song Hui Song Ge Xu Hongli Ji Hongli Ji Xue Yang Xue Yang Gang Li Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana Frontiers in Marine Science lowering O2 light and dark diatom cell composition sinking rate |
| title | Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana |
| title_full | Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana |
| title_fullStr | Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana |
| title_full_unstemmed | Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana |
| title_short | Hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom Thalassiosira pseudonana |
| title_sort | hypoxia lowers cell carbon and nitrogen content and accelerates sinking of a marine diatom thalassiosira pseudonana |
| topic | lowering O2 light and dark diatom cell composition sinking rate |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2025.1529163/full |
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