Dr Aurelija Samuilovienė1, Dr. Anastasija Zaiko3, Dr. Michelle Scriver3, Mrs Urtė Vakarė Drungilaitė1, Mrs Greta Kilmonaitė2, Dr. Sergej Suzdalev2
1Sequench Lithuania, Klaipeda, Lithuania, 2Marine Research Institute, Klaipeda University, Klaipeda, Lithuania, 3Sequench Ltd, Nelson, New Zealand
Biography:
Dr. Aurelija Samuilovienė is senior scientist at Sequench Lithuania. She is a molecular biologist specializing in molecular ecology and molecular approaches to biodiversity assessment and ecosystem monitoring. Her expertise includes eDNA and eRNA metabarcoding, targeted species detection, and the development and application of molecular markers for species identification and functional gene detection.
Abstract:
The Baltic Sea contains approximately 20,000 known shipwrecks, many of which may release hazardous substances such as hydrocarbons, heavy metals and dumped munitions. Assessing their ecological impacts requires approaches that combine chemical contamination with biological responses. Within the Interreg South Baltic Programme project BaltWreck, environmental DNA (eDNA) metabarcoding is used alongside chemical analyses to characterize sediment bacterial communities and support integrated environmental assessment.
Sediment samples were collected from six shipwreck sites in Lithuania, Poland and Germany, together with one reference site. Bacterial communities were analysed using 16S rRNA gene metabarcoding. Community composition was compared among wrecks, with the reference site, and across sampling distances and directions. In parallel, total concentrations of potentially hazardous elements are being determined using X-ray fluorescence (XRF) spectrometry, allowing microbial patterns to be interpreted alongside sediment geochemistry within an integrated assessment framework.
Bacterial community composition differed significantly among individual shipwrecks, indicating that ecological responses were strongly site-specific. Although wreck samples did not consistently differ from the reference site, localized taxonomic associations and marked differences among individual wrecks were detected. Several sulphur-cycling and anaerobic bacterial families were were associated with particular wrecks or combinations of wreck sites. Community composition also varied with distance from wreck structures, while directional patterns were comparatively weak.
These results demonstrate that sediment microbial communities provide a biologically integrated indicator of ecological conditions around historic shipwrecks. Combined with ongoing XRF analyses, they will improve understanding of links between sediment contamination and microbial community structure, strengthening integrated ecological risk assessment of Baltic Sea shipwrecks.