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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences >
Peer-reviewed Journal Articles, etc >
Significant nutrient consumption in the dark subsurface layer during adiatom bloom : a case study on Funka Bay, Hokkaido, Japan
| Title: | Significant nutrient consumption in the dark subsurface layer during adiatom bloom : a case study on Funka Bay, Hokkaido, Japan |
| Authors: | Umezawa, Sachi Browse this author | | Tozawa, Manami Browse this author | | Nosaka, Yuichi Browse this author | | Nomura, Daiki Browse this author | | Onishi, Hiroji Browse this author →KAKEN DB | | Abe, Hiroto Browse this author →KAKEN DB | | Takatsu, Tetsuya Browse this author →KAKEN DB | | Ooki, Atsushi Browse this author →KAKEN DB |
| Issue Date: | 2023 |
| Publisher: | Copernicus Publications |
| Journal Title: | Biogeosciences |
| Volume: | 20 |
| Issue: | 2 |
| Start Page: | 421 |
| End Page: | 438 |
| Publisher DOI: | 10.5194/bg-20-421-2023 |
| Abstract: | We conducted repetitive observations in Funka Bay, Hokkaido, Japan, on 15 February, 4 and 15 March, and 14 April 2019. The diatom spring bloom peaked on 4 March and started declining on 15 March. Funka Bay winter water remained below 30 m depth, which was below the surface mixed-layer and dark-layer depth (0.1 % of the surface photosynthetically active radiation, PAR, depth) on 4 and 15 March. In the subsurface layer at depths of 30-50 m, concentrations of NO3-, PO43-, and Si(OH)(4) decreased by half between these dates, even in the dark. Incubation experiments using the diatom Thalassiosira nordenskioeldii showed that this diatom could consume added nutrients in the dark at substantial rates after pre-culturing to deplete nutrients. Incubation experiments using natural seawater collected in the growing phase of the bloom on 8 March 2022 also showed that nutrient-depleted phytoplankton could consume added nutrients in the dark. We excluded three physical process - water mixing, diffusive transport, and subduction - as possible main reasons for the decrease in nutrients in the subsurface layer. We conclude that the nutrient reduction in the subsurface layer (30-50 m) between 4 and 15 March 2019 could be explained by nutrient consumption by diatoms in the dark in that layer. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/89259 |
| Appears in Collections: | 水産科学院・水産科学研究院 (Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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