Sub-bottom controls on sulphurous seepage in the Mangalia Marine Protected Area, Western Black Sea

The underwater sulphurous seeps in the Mangalia Natura 2000 Marine Protected Area create a distinctive habitat in the Western Black Sea, driven by interactions between subsurface geology, fluid migration, sediment dynamics, and benthic biological communities.

Building on previous geophysical and geochemical investigations carried out by the authors in Mangalia area, we present newly acquired high-resolution sub-bottom profiler (SBP) data, integrated with regional solid Earth datasets accessed through the European Plate Observing System (EPOS) Data Portal, aiming to provide new insights for the shallow subsurface characterization of the seep field.

The SBP profiles, with penetration depths of up to 20-25 m, reveal continuous, well-stratified sedimentary units overlying a high-amplitude acoustic boundary interpreted as consolidated substrata. These stratified successions are locally affected by reflector roughening, subtle flexuring, minor truncations, and zones of reduced acoustic penetration, indicating gas-charged intervals and shallow fluid escape processes, including pockmark development.

By integrating our previous geological, geophysical and geochemical investigations and the newly acquired high‑resolution SBP profiles with related datasets (geological, tectonic, geodynamic) accessed via the EPOS Data Portal, we placed the Mangalia seep field within a broader, interoperable geoscientific framework that enhanced interpretation. This cross‑disciplinary linkage allowed us to test hypotheses about the structural controls on seep localization and to correlate our surveys’ findings with deeper geology and tectonics.

Acknowledgements:

Early-stage researches on geology and tectonics, respectively habitat mapping in the study area was carried out by Irina-Marilena Stanciu and Adrian Popa as part of their PhD stages at the Doctoral School of Geology, Faculty of Geology and Geophysics of the University of Bucharest (both completed now).

In-situ data acquisition was carried out within the PN23300202 (Development of ecosystem-based approaches for the sustainability of marine biological resources (jellyfish, macrophyte algae, mollusks) and production methods to expand their biotechnological use) and PN23300101 (Management and Monitoring of the Marine Environment, as Part of the National Strategy for Assessing Regional and Global Climate Change on the Romanian Continental Shelf of the Black Sea: A Comprehensive Analysis Based on the Development of Geological, Geophysical, Biological, and Geochemical Maps at a Scale of 1:50000) research projects of the CORE Program of the National Institute of Marine Geology and Geo-ecology – GeoEcoMar (Contract No. 4N/30.12.2022), financed by the Romanian Ministry of Research, Innovation and Digitization.

Research employing the European Plate Observing System (EPOS) Data Portal was initiated within the framework of the Integrated Thematic Services in the Field of Earth Observation - A National Platform for Innovation (SETTING) project, co-financed by the European Regional Development Fund (ERDF) through the Operational Programme Competitiveness 2014-2020 (Contract No. 336/390012), and the PN-III-P3-3.6-H2020-2020-0027 project, funded by the Romanian Ministry of Research, Innovation and Digitization, CCCDI-UEFISCDI (Contract No. 8/2021), further continued in the framework of EPOS-RO.