Submarine seepage of fresh groundwater: disturbance in hydrological and chemical structure of the water column in the Gdansk Basin

Anomalies observed in the thermohaline and chemical stratification of the water column in the Gdask Basin indicate a decline in salinity and an increase in temperature in the near-bottom layer. We suggest that these disturbances were caused by fresh groundwater drainage from Cretaceous water-bearing...

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Bibliographic Details
Published in:ICES journal of marine science 1999-12, Vol.56 (a), p.153-160
Main Authors: Falkowska, L, Piekarek-Jankowska, H
Format: Article
Language:English
Subjects:
Brackish
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Summary:Anomalies observed in the thermohaline and chemical stratification of the water column in the Gdask Basin indicate a decline in salinity and an increase in temperature in the near-bottom layer. We suggest that these disturbances were caused by fresh groundwater drainage from Cretaceous water-bearing horizons. Turbulent convection zones are found over the seepage area, with a Rayleigh thermohaline number in the range 10 super(15)-10 super(16). Owing to very strong thermohaline convection, the pycnocline is forced and an intrusion of more saline water ascends into the less saline surface layers. Simultaneous with the observed convection effects, a redistribution of the accumulated nutrients below the pycnocline can be seen in the water column and an improvement of oxygen conditions in the near-bottom water. Copyright 1999 International Council for the Exploration of the Sea
ISSN:1054-3139
DOI:10.1006/jmsc.1999.0616