Macrozoobenthos_BRIDGE-BS_IBER-BAS: Soft-bottom macrozoobenthos from the coastal Bulgarian Black Sea collected in 2022 by IBER-BAS, BRIDGE-BS project

Abundance (individual counts) and biomass (g) of macrozoobenthic taxa at soft-bottom stations along the Bulgarian Black Sea coast, collected during a field survey of IBER-BAS in 2022 as part of project BRIDGE-BS (<a href="https://bridgeblacksea.org/">https://bridgeblacksea.org/</a>). The dataset also contains organism life stages, sediment type (Folk16), and EUNIS L3 habitat type at the stations.
Samples were collected as part of coastal surveys along the Bulgarian Black Sea conducted under BRIDGE-BS project, aimed at gathering spatially referenced data on the biodiversity, community structure and ecological condition of selected dominant soft-bottom benthic ecosystems to complement existing datasets in the area and fill gaps therein. An attempt was made to cover as many different MSFD national habitat types as possible based on previous data and modeling (Emodnet Seabed habitats). Sampling was performed by Van Veen grab (0.05 m2 sampling area) and diver-operated hand corer (10 cm internal diameter, ~20 cm sediment penetration depth). Samples were sieved on a 0.5 mm mesh sieve, and fixed in 10% formaldehyde-seawater solution until analysis. In the laboratory, samples were hand-sorted under a stereomicroscope to the lowest possible taxonomic level (preferably species), and counted. Individual biomass was measured as preserved wet weight on an analytical scale to the nearest 0.0001 g; mollusks were weighed with their shells, and tubicolous polychaetes and hermit crabs were taken out of their tubes/shells before weighing.