Pockmarks and associated fresh submarine groundwater discharge in the seafloor of Puck Bay, southern Baltic Sea.
Sci Total Environ
; 942: 173617, 2024 Sep 10.
Article
em En
| MEDLINE
| ID: mdl-38815837
ABSTRACT
This is the first well-documented report on the occurrence of pockmarks in Puck Bay. Pockmarks in the seafloor of Puck Bay were discovered during a hydroacoustic survey carried out in 2020. They are located at a depth of 25-27â¯m in the southwestern part of the bay. Significant depletion of chloride (Cl-) concentrations in sediment pore water was found within the depressions. Most likely, the formation of pockmarks was due to groundwater flow through the Miocene-Pleistocene system of aquifers, which extends from land to the bay area. One-dimensional modeling of vertical Cl- concentration profiles in pore water revealed the upward flow of freshened groundwater within the pockmarks. The magnitude of submarine groundwater discharge (SGD) was estimated to vary from 1.53·10-2 to 18·10-2â¯L·m-2·h-1. The effect of groundwater seepage was also observed at 3â¯cm above the seafloor within the pockmarks, which was identified as a decrease in salinity of approximately 0.12 PSU compared to reference sites. Furthermore, due to the effect of water advection, SGD can be detected even several meters above the seafloor as a decrease in salinity values within the thermocline layer.
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MEDLINE
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En
Ano de publicação:
2024
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Article