Within the framework of a joint Russian - American - Norwegian expedition, NPA "Sevmorgeologiya" performed for the first time a multidisciplinary geological and ecological research of the St. Anna Trough over a regular network on a scale of 1:1000000. The interdisciplinary approach included the investigation of all the main links of the ecosystem: aerosols, sediment fluxes, suspended matter, water column, and bottom sediments. Special attention was paid to the lithological study of the surface layer of the bottom sediments. The parameters of the grain-size fraction structure were calculated and the distribution maps of the principle fractions (sand, silt, and clay) and of the mean particle size (integrated grain-size parameter) were constructed, based on the grain-size analysis of 13 fractions, performed for 70 sediment cores.