Intermediate plumes of low oxygen in the southeastern Baltic Sea
Closely spaced CTDO profiling on the pathway of saltwater flow in the southeastern Baltic Sea in August and December 2019 revealed low oxygen intermediate layers-plumes with dissolved oxygen concentration (DOC) less than 2 mg/l under the upper boundary of permanent halocline. At the same time, DOC i...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-01-01
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| Series: | Oceanologia |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0078323421001020 |
| _version_ | 1811159952931160064 |
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| author | Maria Golenko Vadim Paka Victor Zhurbas Andrey Korzh Alexey Kondrashov |
| author_facet | Maria Golenko Vadim Paka Victor Zhurbas Andrey Korzh Alexey Kondrashov |
| author_sort | Maria Golenko |
| collection | DOAJ |
| description | Closely spaced CTDO profiling on the pathway of saltwater flow in the southeastern Baltic Sea in August and December 2019 revealed low oxygen intermediate layers-plumes with dissolved oxygen concentration (DOC) less than 2 mg/l under the upper boundary of permanent halocline. At the same time, DOC in the underlying layers was higher and reached 5.0–5.3 mg/l. In order to test the hypotheses about the origin of the intermediate hypoxic plumes, numerical hydrodynamic modelling was performed for time intervals including the measurement periods. The model was validated against bottom current velocity instrumental measurements by a TCM (Tilt Current Meter) moored on the track of the CTDO profiling. Numerical experiments with Lagrangian particles of neutral buoyancy coupled with the operational circulation model showed that sub-halocline hypoxic intermediate layers in the southern part of the Eastern Gotland Basin and in the Gdańsk Basin could be formed as a result of intrusion into the underlying bottom layer of denser, moderately oxygenated water from the Słupsk Furrow, which replaced the old anoxic and hypoxic water of Gotland and Gdańsk origin. It is assumed that cyclonic eddy activity above the saltwater flow along sloping bottom caused fragmentation of the hypoxic intermediate layer into separate plumes. The hypoxic intermediate layers in the Słupsk Furrow, in accordance with the results of monitoring measurements and modelling the motion of particles of neutral buoyancy, could be formed in the Bornholm Basin and moved eastward over the Słupsk Sill. |
| first_indexed | 2024-04-10T05:49:26Z |
| format | Article |
| id | doaj.art-2b3459dc498c479385e06df4c423bf85 |
| institution | Directory Open Access Journal |
| issn | 0078-3234 |
| language | English |
| last_indexed | 2024-04-10T05:49:26Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Oceanologia |
| spelling | doaj.art-2b3459dc498c479385e06df4c423bf852023-03-05T04:23:01ZengElsevierOceanologia0078-32342023-01-01651100116Intermediate plumes of low oxygen in the southeastern Baltic SeaMaria Golenko0Vadim Paka1Victor Zhurbas2Andrey Korzh3Alexey Kondrashov4Corresponding author at: Shirshov Institute of Oceanology, Russian Academy of Sciences, 36 Nahimovskiy pr., Moscow, 117997, Russia.; Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, RussiaClosely spaced CTDO profiling on the pathway of saltwater flow in the southeastern Baltic Sea in August and December 2019 revealed low oxygen intermediate layers-plumes with dissolved oxygen concentration (DOC) less than 2 mg/l under the upper boundary of permanent halocline. At the same time, DOC in the underlying layers was higher and reached 5.0–5.3 mg/l. In order to test the hypotheses about the origin of the intermediate hypoxic plumes, numerical hydrodynamic modelling was performed for time intervals including the measurement periods. The model was validated against bottom current velocity instrumental measurements by a TCM (Tilt Current Meter) moored on the track of the CTDO profiling. Numerical experiments with Lagrangian particles of neutral buoyancy coupled with the operational circulation model showed that sub-halocline hypoxic intermediate layers in the southern part of the Eastern Gotland Basin and in the Gdańsk Basin could be formed as a result of intrusion into the underlying bottom layer of denser, moderately oxygenated water from the Słupsk Furrow, which replaced the old anoxic and hypoxic water of Gotland and Gdańsk origin. It is assumed that cyclonic eddy activity above the saltwater flow along sloping bottom caused fragmentation of the hypoxic intermediate layer into separate plumes. The hypoxic intermediate layers in the Słupsk Furrow, in accordance with the results of monitoring measurements and modelling the motion of particles of neutral buoyancy, could be formed in the Bornholm Basin and moved eastward over the Słupsk Sill.http://www.sciencedirect.com/science/article/pii/S0078323421001020Baltic SeaClosely spaced CTDO profilingSaltwater inflowsHypoxic intermediate layersModellingLagrangian particles of neutral buoyancy |
| spellingShingle | Maria Golenko Vadim Paka Victor Zhurbas Andrey Korzh Alexey Kondrashov Intermediate plumes of low oxygen in the southeastern Baltic Sea Oceanologia Baltic Sea Closely spaced CTDO profiling Saltwater inflows Hypoxic intermediate layers Modelling Lagrangian particles of neutral buoyancy |
| title | Intermediate plumes of low oxygen in the southeastern Baltic Sea |
| title_full | Intermediate plumes of low oxygen in the southeastern Baltic Sea |
| title_fullStr | Intermediate plumes of low oxygen in the southeastern Baltic Sea |
| title_full_unstemmed | Intermediate plumes of low oxygen in the southeastern Baltic Sea |
| title_short | Intermediate plumes of low oxygen in the southeastern Baltic Sea |
| title_sort | intermediate plumes of low oxygen in the southeastern baltic sea |
| topic | Baltic Sea Closely spaced CTDO profiling Saltwater inflows Hypoxic intermediate layers Modelling Lagrangian particles of neutral buoyancy |
| url | http://www.sciencedirect.com/science/article/pii/S0078323421001020 |
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