Changes in coastal ecosystems affected by overburden dumping from amber open-cut mining on the Sambia Peninsula (Baltic Sea).

The Sambia Peninsula (Kaliningrad region) is historically well known for its amber mining. The 2019 year was the last year of direct overburden disposal into the Baltic Sea as a part of technological amber mining process. The extremely high-suspended particulate matter concentrations during that disposal were recorded immediately after the discharge of significant volumes of pulp and reached 200 mg/L. The impact of pulp discharge had sequentially suppressed plankton communities development due to the high content of suspended solids and afterwards stimulated plankton development due to the glauconite infusion. Cladocera were the most sensitive group to the effects of suspended matter. According to the preliminary forecast, when the pulp discharge stops, the restoration of plankton communities may take from 1 to 2 seasons to 1 year for different groups. This is due to the timing of the removal of fine suspended particulate matter from sediments and the possibility of secondary entry during resuspension.

[Sulfate-Reducing Bacterial Communities in the Water Column of the Gdansk Deep (Baltic Sea)].

Biodiversity of sulfate-reducing bacterial communities in the water column of the Gdansk Deep, Baltic Sea, where H2S had been detected in near-bottom layers, was analyzed by PCR with primers for the 16S rRNA genes of six major phylogenetic subgroups of sulfate-reducing bacteria (SRB). Using denaturing gradient gel electrophoresis followed by sequencing, the nucleotide sequences of reamplified dsrB gene fragments from investigated water samples were determined. For the first time the presence of nucleotide sequences of the dsrB gene was detected by PCR in the water samples from all hydrochemical layers, including subsurface oxic waters. The presence of the 16S rRNA genes of representatives of Desulfotomaculum, Desulfococcus-Desulfonema-Desulfosarcina, and Desulfovibrio-Desulfomicrobium SRB subgroups was also revealed throughout the water column of the Gdansk Deep. Analysis of translated amino acid sequences encoded by the dsrB gene demonstrated the highest homology with the relevant sequences of uncultured SRB from various marine habitats.