Articles | Volume 8, issue 1
Research article
03 Jan 2020
Research article |  | 03 Jan 2020

Potential links between Baltic Sea submarine terraces and groundwater seeping

Martin Jakobsson, Matt O'Regan, Carl-Magnus Mörth, Christian Stranne, Elizabeth Weidner, Jim Hansson, Richard Gyllencreutz, Christoph Humborg, Tina Elfwing, Alf Norkko, Joanna Norkko, Björn Nilsson, and Arne Sjöström

Data sets

Multibeam bathymetry from Fifång Deep and Asköfjärden, southern Stockholm archipelago M. Jakobsson

Multibeam bathymetry from southeast of Tvärminne Zoological Station in southern Finland archipelago M. Jakobsson

Short summary
We studied coastal sea floor terraces in parts of the Baltic Sea using various types of sonar data, sediment cores, and video. Terraces (~1 m high, > 100 m long) are widespread in depths < 15 m and are formed in glacial clay. Our study supports an origin from groundwater flow through silty layers, undermining overlying layers when discharged at the sea floor. Submarine groundwater discharge like this may be a significant source of freshwater to the Baltic Sea that needs to be studied further.