Halina Piekarek-Jankowska

Abstract

The article presents alterations observed in interstitial water chlorinity and (180, D) isotope composition and in near-bottom salinity caused by groundwater discharge to the Puck Bay from Cretaceous, Tertiary and Quaternary aquifers. The groundwater seepage decreases the chlorinity of interstitial water and the salinity of near-bottom water. The comparison of the oxygen and hydrogen isotope composition of underground, interstitial and near-bottom waters indicated a reduction of the content of heavy isotopes in the interstitial water and thus gave evidence of freshwater seepage through the sea floor. Zones with abnormal interstitial water chlorinity and diminished salinity of near-bottom water were used to determine drainage areas for fresh groundwater on the Puck Bay bottom.

Keywords: submarine groundwater discharge, chlorinity of porewaters, salinity of near-bottom waters, isotope (180, D), Puck Bay, Baltic Sea

Halina Piekarek-Jankowska, Institute of Oceanography, University of Gdańs k al. Marszałka Piłsudskiego 46, 81-378 Gdynia, Poland