The dataset comprises grain size analysis data of bottom sediments from the lower sector of the Danube River. The data were collected during two research cruises conducted March 23 - April 3, 2023 and September 20 - September 29, 2023, as part of the national project “Optimizing the sustainable management of natural resources, enhancing water security, and increasing the resilience of ecosystems in the Lower Danube Basin, impacted by climate change and anthropogenic interventions” (PN 23 30 03 03).
A total of 81 sediment samples were collected during the first expedition, in the following Danube sectors: Isaccea (Mile 54-58), Giurgiulești (Mile 72-76.5), Seimeni (Km 287-294), Downstream Oltenița (Km 400-407) and Upstream Oltenița (Km 420-429) and 92 during the second, from this sectors: Ceatal Izmail (Km 114.5-111.5 Chilia Branch, M41-44 Tulcea Branch, M45.5–52.5 Danube), Reni (M63-67), Gropeni (Km 186–196.5), Fermecatu (Km 317–325) and Turcescu (Km 338.5–347). Sampling was performed using a Van Veen grab by the GeoEcoMar research team. The dataset aims to support the characterization of sediment texture and the evaluation of spatial and temporal variability of bottom sediments in this section of the Danube River.